Volume 23, Issue 1

Nanocomposite films have been prepared from chitosan, cinnamaldehyde, Nigella sativa or blackseed oil, and silver nanoparticles (NPs) biosynthesized in Azadirachta indica or neem leaves’ extract. The methodology involved simple blending of components through “green chemistry” route. The films obtained were soft and foldable. The morphology by scanning electron microscopy confirmed the inclusion of NPs in the films. Microbial penetration study demonstrated that the films offered good resistance to secondary bacterial infection. The antibacterial study against Staphylococcus aureus (ATCC 29213) and E. coli (ATCC 25922) indicated moderate antibacterial behavior of the films. The swelling behavior in water, phosphate buffer saline, and simulated wound fluid was found to be appropriate for use as wound dressings. The films were biodegradable in soil and showed good thermal stability up to 200°C.

In this article, CaCu 3 Ti 4 O 12 (CCTO) and Zr-doped CaCu 3 Ti 3.95 Zr 0.05 O 12 (CCTZO) particles were fabricated by the sol–gel combustion method, and then, CCTO/LDPE and CCTZO/LDPE composite films were prepared by the melt-blending and hot briquetting. The microstructures and dielectric properties of fillers and LDPE composites were investigated in detail. Results showed the lattice expansion of CCTZO caused by Zr doping reduced grain size, increased size uniformity, and remarkably reduced dielectric loss and conductivity. Compared with CCTO, small-size CCTZO enhanced dielectric constant of LDPE by 88.5% (∼3.45) due to enhanced interfacial polarization included by ultrahigh interfacial area (∼3.0 × 10 5  m 2 ), remaining a lower loss tangent (0.013) and conductivity (2.42 × 10 −13  S·cm −1 ) for the 10 vol% CCTZO/LDPE composite. Furthermore, finite element simulation proofed small-size and uniform CCTZO particles played a prominent role in homogenize electric field distribution in LDPE composite, which was beneficial for the use of these composites in the high voltage power cable field. Graphical abstract Small-size CaCu 3 Ti 3.95 Zr 0.05 O 12 enhanced dielectric constant of LDPE by 88.5% due to enhancing interfacial polarization included by ultrahigh interfacial area (∼3.0 × 10 5  m 2 ) and played a prominent role in homogenize electric field distribution in LDPE composite.

Octenyl succinic anhydride (OSA) starch is widely used to stabilize emulsions. Nevertheless, the poor compatibility of starch with hydrophobic groups has restricted the performance of OSA modification. In this work, potato starch was pre-treated once or twice (dry heating, acetylation, and acid modification) prior to OSA modification. Pre-treatments increased the degree of substitution (DS), hydrophobicity, hydrophilicity, and decreased amylose content of OSA starches, with dual pre-treatments having greater effects. Among all pre-treatments, acid modification followed by dry heating resulted in the greatest OSA modification (DS: 0.015) and water-binding capacity (155%). Meanwhile, acid modification followed by acetylation produced OSA starch with the highest oil-binding capacity (290%). Scanning electron microscopy revealed that the granular deformation of dual pre-treated OSA starches was greater compared to single pre-treated and non-pre-treated OSA starches (O). Dual pre-treated OSA starches (ADO, 7%; ACO, 8%) had lower amylose contents than those of single pre-treated (AO: 12%, CO: 17%, DO: 21%) and O (36%). All the pre-treatments reduced the setback viscosity of OSA starch to a lower range (70–394 cP), simultaneously decreasing their retrograde tendency. This study suggested that dual pre-treatments could improve the efficiency of OSA modification and produce OSA starch with greater emulsifying potential. Graphical abstract Pre-treatments of dry heating, acetylation, and acid modification could enhance the emulsifying potential of OSA-modified starch.

Fatigue failure, commonly encountered in rubber materials, is a critical issue. In this study, the compression fatigue tests of filled styrene-butadiene rubber (SBR) under different loading conditions were performed, applying cylindrical specimens. A stress–strain curve and modulus drop curves were generated by nine fatigue loading cases, covering different R ratios in the range of 0 < R < 1. The temperature variation in the process of compression fatigue was explored. Three different approaches were applied to investigate the fatigue life of the SBR (it is used twice hence abbreviation should be used) vulcanizates. These methods were validated in assessing the fatigue failure of the specimens. According to the experimental fatigue life, a fatigue life prediction model based on strain amplitude as the damage parameter was established. The results demonstrated that both R ratio and strain amplitude could affect the fatigue life. For all the loading cases, the fatigue life generally increases with the increase of R ratio. Under the compression loading condition, the narrower range of strain and the lower mean strain are beneficial to the fatigue resistance of rubbers, which also indicates a larger pre-load provides much higher fatigue resistance. During the fatigue loading, the temperature rises rapidly until it reaches a peak value, then drops slightly, and finally reaches a plateau.

The properties and compatibility of bio-based PA56 and polyethylene terephthalate (PET) polymers were studied in detail. The experimental results showed that when compared with PET, bio-based PA56 had better moisture absorption, softness, and dyeing characteristics. By calculating and analyzing the macromolecular structures of bio-based PA56 and PET, the difference in solubility was obtained as 4.18 Cal 0.5 ·cm 1.5 ·mol −1 . Thermodynamic analysis showed that the measured change in mixing enthalpy far exceeds the range of the compatible system when the proportion of bio-based PA56 exceeded 15%. When the content of bio-based PA56 in PET exceeded 20%, the glass transition temperature of the blends with different proportions all had double peaks and the eutectic phenomenon was not observed. Scanning electron microscopy was used to observe the cross-section morphology of bio-based PA56/PET blends before and after etching. We found that the interface between the two phases was clear and a “sea-island” dispersed structure was formed. The results of the analysis indicated that the compatibility of the bio-based PA56 and PET was not good.

As the key components of sealing applications, rubber seals are subject to complicated environmental conditions during the service lifetime. In this study, the aging of three typical rubber materials, ethylene–propylene–diene monomer rubber, liquid silicone rubber, and fluorine rubber, was tested under different high- and low-temperature cycle aging environments. The experimental results confirm that the reciprocating temperature cycle causes a type of fatigue failure, which could result in an increase in the rubber compression set. In addition, a novel accelerated aging test method was proposed based on the dominant damage mechanism of rubber material caused by the temperature cycle treatments. Based on this method, the long-term aging test results of rubber samples under high- and low-temperature cycle conditions can be predicted. This method could significantly shorten the aging test time and reduce the test cost.

In the electrospinning process, the Taylor cone, as the jet source, directly affects the jet movement and the quality of the fiber membrane. Therefore, to understand the formation mechanism of the Taylor cone intuitively, a multiphysics coupling model that comprehensively considers the gravitational field, electrostatic field, and fluid field is established, and numerical simulations are conducted in this study. First, we construct a level-set function and analyze the force of the droplet. The gravity, surface tension, and electric field force are coupled to the incompressible Navier–Stokes equation as volume forces, and the nonconservation of the droplet area is solved by approximating the Dirac function with a smooth function. Subsequently, the deformation of the electrospun polyacrylonitrile (PAN) Taylor cone under different process parameters is simulated. Finally, data obtained from the numerical simulation and the average diameter of the electrospun PAN fiber membrane are analyzed via gray relational analysis. The results show that the volume force is the key factor affecting the average diameter of the fiber membrane (the correlation is 0.934). This article provides an effective reference and basis for the analysis and control of the electrospinning process.

Using plant leaf fibers as reinforcements in thermo-plastic resins to produce affordable and lightweight composites is the subject of growing interest in research. Although these fibers have several advantages over synthetic fibers, mechanical characteristics of composites such as moisture absorption, poor wettability, and insufficient adhesion between the matrix and the fiber cause disadvantages. To overcome these issues, in this experimental study, two leaf-based plant fibers are hybridized and the composites have been fabricated by hand lay-up process. The composites were subjected to several tests. The results showed that the hybridization of sisal and pineapple leaf fiber (PALF) increases the mechanical strength of the composite by a maximum tensile strength of 3.59 kN, a little lower flexural strength than the individual fiber, and a noticeably higher compressive strength. The results further showed that the decreased affinities for moisture content and the aged composites seem to be prone to be hydrophilic. Findings of the experiments reveal that the hybridization of sisal and PALF has a significant influence on the properties of the composites. The scanning electron microscopy micrographs of fractured surfaces have been examined, and the findings have effectively been investigated.

The foamed polypropylene (PP) composites were prepared by injection molding process. Fourier’s law and software were used to calculate and simulate the internal temperature distribution of PP composites, respectively, and the influence of the temperature distribution on the foaming quality of foamed PP composites was further analyzed. The result showed that the calculative and simulated results of temperature distribution in different thermal transfer directions had great reproducibility. In different isothermal planes, the temperature from the nozzle to the dynamic mold gradually decreased. The isothermal plane with a temperature of 370.36 K had a better foaming quality, average diameter of cell and cell density were 28.46 µm and 3.7 × 10 10 cells·cm −3 , respectively. In different regions of the same isothermal plane, the temperature gradually decreased from the center to the edge. The foaming quality in the region (c) at a temperature of 335.86 K was ideal, and the average diameter of cell and the cell density were 26.5 µm and 2.39 × 10 10 cells·cm −3 , respectively. This work could provide prediction for improving the foaming quality of foamed polyolefin composites.

In the present work, 4-methylcatechol oligomer has been prepared by using enzyme-catalyzed polymerization in water and preliminary evaluations as stabilizing agent in polypropylene (PP) was performed. In comparison with intrinsic PP, the oxidation onset temperature of the 4-methylcatechol oligomer/PP composite increased by 66°C, and the oxidation induction time increased by 40 min. In addition, the mixing of a 4-methylcatechol oligomer with PP (i.e., in the formation of a 4-methylcatechol oligomer/PP composite) did significantly enhance the long-term stability of PP in a thermal oxidative environment. Moreover, the tensile strength of this composite did not significantly decrease after aging for 800 h in an air atmosphere at 120°C. These results show that the addition of a 4-methylcatechol oligomer will markedly delay the aging and degradation of PP materials, even under extreme conditions. Thus, an enzyme-catalyzed polymerization of phenol compounds may provide a new avenue toward the preparation of novel antioxidants.

For microscopic analysis of the effect of doping with carbon nanotubes (CNTs) of different radii on the thermal and mechanical properties of addition liquid silicone rubber (ALSR) composites, models of pure silicone rubber and silicone rubber composites containing CNTs of different radii were constructed based on a molecular dynamics approach using vinyl-capped polydimethylsiloxane (VPDMS) as the base polymer and polyhydroxymethylsiloxane (PHMS) as the cross-linker. The thermal and mechanical properties and microstructures of the different models were analyzed and compared. It was found that the doping of CNTs could change the thermomechanical properties of the composites, and the doping of CNTs with small radius had a more positive effect on the material, the thermal conductivity, glass transition temperature, and mechanical properties of the composites are improved. Due to the doping of CNTs, the free volume percentage and the mean square displacement of the composites are reduced. It is noteworthy that during the modeling and optimization process, there are molecular chains that pass through the large radius CNTs, and the structural properties of the composite CNTs themselves play a more critical role in the enhancement effect of the thermodynamic properties of the composites compared to the binding energy and free volume.

This study aimed to ascertain the influence of poly(3-acrylamidopropyl trimethylammonium chloride- co -acrylic acid) [P(ATC- co -AA)] on the adhesion, film properties, desizability of cornstarch, and reveal a suitable mole percentage of ATC units on the P(ATC- co -AA) for acquiring a new starch-based size [S- g -P(ATC- co -AA)]. A series of S- g -P(ATC- co -AA) samples were synthesized by the graft polymerization of acid-converted cornstarch with ATC and AA monomers. Their adhesion, film properties, and desizability were assessed. The results displayed that the P(ATC- co -AA) branches could significantly improve the adhesion to cotton fibers and diminish the film brittleness of starch. Under similar grafting ratio, the adhesion and desizability of S- g -P(ATC- co -AA) depended on the mole percentage of ATC units. Increasing the percentage favored the adhesion but disfavored the desizability. The percentage displayed a low effect on the film properties. S- g -P(ATC- co -AA) with a mole percentage of 57.7% presented good sizing properties and easy desizing, which had potential application in cotton warp sizing.

To optimize the surface performance of the composites of polyamide 66 and continuous glass fiber (50/50, weight ratio), poly(hexamethylene isoftalamide- co -terephthalamide) (PA6I-6T) was introduced. The composites were prepared by a twin-screw extruder, and the effect of PA6I-6T on the thermal and mechanical properties, as well as surface appearance was investigated. The results showed that the crystallization temperature and the melting point of the composites decreased with increasing the amount of PA6I-6T. The Jeziorny method proved that the presence of PA6I-6T did not change the nucleation mode and the crystal growth of PA66 in the hybrid matrix, and the Mo method revealed that the crystallization rate of PA66 decreased first and then increased with the increase of the PA6I-6T content. The reduction in the “floating fiber” on the surface of the composites was attributed to the decrease of the crystallization rate of PA66 in the presence of PA6I-6T. It was shown that the composites with smooth surface had a large melt flow index. Moreover, the composites with high content of PA6I-6T had low heat deformation temperatures. The mechanical properties of the composites did not change significantly with the increase of the PA6I-6T content. Scanning electron microscope (SEM) images revealed that glass fiber was evenly distributed in the matrix and strongly oriented parallel to the injection direction.

This article proposes the preparation and microwave thermal cured (MTC) epoxy-modified phenolic fibers for the first time. Epoxy-modified thermoplastic phenolic resin was first prepared in acidic condition using phenol, formaldehyde, and epichlorohydrin as the reactants, and then underwent additive reaction with formaldehyde to obtain epoxy-modified thermosetting phenolic resin, which was converted into nascent fibers through wet spinning. Finally, epoxy-modified phenolic fibers were obtained through different curing methods including solution cured, solution thermal cured, microwave cured, MTC, and was characterized by infrared spectroscopy, microscopic infrared imaging, nuclear magnetic resonance, thermogravimetric analysis, and scanning electron microscopy. The experiment results show that MTC epoxy-modified phenolic fibers have optimal mechanical property with ultimate elongation of 4% and breaking strength of 133 MPa. Graphical abstract

The thermal decomposition behavior of polyacrylate pressure-sensitive adhesive (PSA) at heating rates of 4, 6, 8, and 10 K·min −1 was measured by thermogravimetric analysis (TGA). The kinetic parameters for thermal decomposition reaction of the polyacrylate adhesive were obtained from TG profile by differential method and integral method (Kissinger, general integral, MacCallum–Tanner, Šatava–Šesták, Agrawal, and Flynn–Wall–Ozawa), the results show that the main decomposition stage of the polyacrylate adhesive starts at 301°C and its activation energy is 142.68 kJ·mol −1 , the pre exponential factor is 10 9.55 , the decomposition mechanism obeys Avrami–Erofeev equation and its decomposition kinetic equation can be expressed as: d α /d T = (10 9.55 / β )[(1 − α )/2][−ln(1 − α )] −1 exp(−1.7161 × 10 4 / T ). The storage life of PSA at 25°C was predicted to be about 19 years by isoconversional method.

Due to the shortage of petroleum resources, poly(lactic acid) (PLA), a biodegradable polymer, has been widely considered as a replacement for traditional petroleum-based polymers. Therefore, multifunctional PLA composites have become increasingly popular. In this study, conductive carbon nanotubes (CNTs) and magnetic nano-Fe 3 O 4 fillers were melt-blended with PLA. The impact of CNTs and nano-Fe 3 O 4 composition on the electrical and electromagnetic interference (EMI) shielding properties of PLA nanocomposites was investigated in detail by adjusting the CNTs-to-nano-Fe 3 O 4 ratio. When the hybrid filler content was fixed at 10 wt%, the electrical conductivity results indicated that the addition of single CNTs could effectively improve the conductivity of the nanocomposites, while nano-Fe 3 O 4 contribution was hardly noted. A suitable ratio of electromagnetic hybrid fillers can yield excellent synergistic effects in EMI shielding properties. The nanocomposites containing CNTs and nano-Fe 3 O 4 in a 50:50 ratio exhibited excellent electrical conductivity (90.6 S·m −1 ) and EMI shielding effectiveness (EMI SE ∼ 40.5 dB). This is primarily because CNTs provide good electrical conductivity, but the addition of magnetic nano-Fe 3 O 4 provides additional interfacial polarization and eddy current losses caused by its dielectric and magnetic properties. These properties synergistically result in an impedance mismatch, dielectric loss, and polarization relaxation of the composite materials, improving the shielding properties against electromagnetic waves. Further, it was found that changing the ratio of electromagnetic hybrid fillers also affected electromagnetic wave absorption. When the ratio of CNT-to-nano-Fe 3 O 4 was 25:75, the nanocomposites had an EMI SE of 24.6 dB, and the absorptivity could reach the maximum (40.3%). Thus, this study provides a valuable reference for preparing multifunctional polymer nanocomposites by constructing electromagnetic hybrid filler networks.

Polyamide composite reverse osmosis (RO) membranes occupy an important position in water treatment. However, membrane fouling, especially biofouling, can lead to a significant decrease in membrane permeability. Therefore, reducing biological contamination is a significant and important property of an RO membrane. In this article, a hypothesis on the development of a new kind of RO membrane for antibacterial purposes was prepared by the modification of gallic acid (GA) and silver nanoparticles (AgNPs). Then, experiments were carried out to verify the hypothesis, getting a modified RO membrane with the composite of GA@AgNPs. The water flux of the GA@AgNPs RO membrane was 31.1 L·m −2 ·h −1 , which was 46.7% higher than that of the original membrane, while the rejection rate of salt remained at 93.8–97.6%. Moreover, the GA@AgNPs RO membranes exhibited outstanding antibacterial properties with more than 99.9% antibacterial efficiency against both Escherichia coli and Staphylococcus aureus . Our work provides a new idea for solving the problem of biofouling RO membranes.

Biomass films with ultraviolet (UV)-shielding ability have attracted considerable attention. Curcumin was introduced into castor oil-based polyurethane (CCPU) as a chain extender, which was melt with polylactic acid (PLA) as a reinforcement to obtain biomass UV-shielding film. The excellent UV absorption and antioxidant qualities of curcumin contributed to the impressive UV-shielding capacity (97.6% UV radiation absorption) and antioxidant (51% free radical scavenging) of PLA/CCPU-20 film. In the scanning electron microscopic images of film fracture, the mixing of CCPU elastomer into the PLA matrix caused the blend films to exhibit significant toughening fracture characteristics compared to the pure PLA film. The excellent thermal stability, low water swelling degree, and low water solubility of PLA/CCPU blend films were maintained after CCPU was added to the PLA matrix. Therefore, the PLA/CCPU blend films can be considered as a potential packaging material because of its favorable UV-shielding properties and film stability. Graphical abstract Schematic for the preparation of the PLA/CCPU blend films.

A thorough comparative analysis was conducted between pure epoxy and a novel epoxy composite that included bentonite and WO 3 nanoparticles in varying ratios. This study examined five distinct novel epoxy samples (E00, EB0, EBW1, EBW2, and EBW3) to assess their radiation shielding efficiency (RSE), taking into account the addition of bentonite and WO 3 nanoparticles. Furthermore, the study compared the RSE of pure epoxy with that of the novel epoxy composite. To evaluate the radiation shielding ability of the studied epoxy samples, a few radiation shielding parameters such as linear attenuation coefficient (LAC), mass attenuation coefficient (MAC), mean free path (MFP), RSE, and transition factor ( I / I 0 ) were calculated. The RSE values of the epoxy samples were E00 (63.41%), EB0 (87.17%), EBW1 (98.26%), EBW2 (99.82%), and EBW3 (99.99%) at an energy of 0.06 MeV with 4 cm thickness. With the increase in the incident energy, the half-value layer and MFP values were increased, whereas the LAC and MAC values decreased. In conclusion, it can be stated that the sample EBW3 is more suitable among the five epoxy samples studied for attenuating the incident photon energy from 0.06 to 1.33 MeV. Noteworthily, the obtained results demonstrate that the addition of WO 3 nanoparticles enhances the shielding ability of epoxy when compared to the addition of the same amount of bentonite.

The present study focuses on the evaluation of a novel prolonged action fertilizer that has been encapsulated by a combination of carboxymethyl cellulose (CMC) and humic acid (HA). The aim of this research was to investigate the release of the essential plant nutrients: phosphorus, nitrogen, and potassium. This study investigated the material composition and nutrient release properties of a novel prolonged action fertilizer encapsulated by CMC and HA. The release of these nutrients was determined by quantifying their concentrations over time using various analytical techniques, such as photometric, titrimetric, and flame photometric methods. The results revealed that the CMC/HA matrix effectively controlled the nutrient release, with extended-release durations observed under acidic (pH 5.0) and neutral (pH 7.0) conditions compared to alkaline environments (pH 8.5). This indicates that the encapsulated fertilizer is well suited for a variety of soil pH conditions, particularly in acidic and neutral soils. This information could have important implications for the development of more sustainable and environmentally friendly fertilizer technologies.

The present work aims to fabricate new inexpensive epoxy-based composites with a concentration described by the formula (90 − x )epoxy + 10Sb 2 O 3 + x PbO, where x = 5, 10, 15, and 20 wt%. The impacts of the substitution of epoxy by PbO on the composite density and radiation shielding properties of the fabricated composites were studied. The density of the fabricated composites varied between 1.30 and 1.49 g·cm −3 , enriching the PbO concentration. Utilizing the narrow beam transmission method, the linear attenuation coefficient (LAC) of the fabricated composites was measured using the NaI (Tl) detector as well as radioactive sources Am-241 and Cs-137. The LAC increased by 84% and 18% at gamma-ray energy of 0.059 and 0.662 MeV, when the PbO concentration raised between 5 and 20 wt%, respectively. Then the transmission rate and half-value layer of the fabricated composites were reduced by raising the PbO concentration. Therefore, the fabricated composite has good shielding properties in the low gamma-ray energy interval to be suitable for medical applications and low radioactive waste container constructions.

With the rapid development of smart wearable devices and the urgent demands for new energy resources, fibrous flexible power supply units had attracted a lot of interest. Here, we reported the fabrication of polylactic acid (PLA) piezoelectric nanofibrous yarn-based fabric through conjugated electrospinning and weaving process. Five kinds of PLA yarns including poly( l -lactide) (PLLA), poly( d -lactide) (PDLA), PLLA positive/PDLA negative, PDLA positive/PLLA negative, and PLLA/PDLA mixture (1:1 w/w) ones were prepared and investigated. Among these, the PLLA/PDLA yarn had more uniform and oriented structure with 301 MPa tensile strength, which could meet the requirement of weaving. A 4 cm × 4 cm woven PLLA/PDLA fabric could provide a maximum current of 90.86 nA and a voltage of 8.69 V under 5 N force, and the piezoelectricity could be enhanced by the fabric area and the applied force. This approach may be helpful for the design of wearing generators.

Epoxy resin (EP)/cyanate ester (CE) copolymer, an important structural material with high temperature resistance and low dielectric constant in aerospace, microelectronics, and related fields, is still of great flammability danger. In this work, copper phenyl phosphonate (CuPP), a flame retardant used in EP/CE copolymer was synthesized by the reaction of phenyl phosphonic acid and copper nitrate trihydrate. The fire and thermal behavior of EP/CE/CuPP composites were studied in detail. The results suggested that the UL-94 rating and limiting oxygen index of EP/CE composite with 5 wt% CuPP (EP/CE/CuPP5) reach V-1 level and 30.6%, respectively. Compared with pure EP/CE copolymer, the peak heat release rate and total heat release values of EP/CE/CuPP5 decreased by 34.5% and 18.9%, respectively. The glass transition temperature of EP/CE/CuPP composite is higher than that of pure EP/CE copolymer, suggesting that the fire-retardant composite has higher work temperature and better heat resistance.

The oxidation of natural rubber (NR) leads to a decrease in mechanical properties, even resulting in failure of NR products. Many studies focusing on this single factor have failed to fully elucidate the impact of tropical island environment on NR properties. Based on this concern, the synergistic effect of thermal oxygen and ultraviolet (UV) aging on NR was systematically studied. The results revealed that thermal oxygenation can promote UV aging, which leads to the appearance of surface cracks and deepening of color. With the extension of aging time, the mechanical properties of NR correspondingly decreased. Besides, to deeply understand the mechanism of the synergistic effect of thermal oxygen and UV aging on NR, we selected squalene to simulate and analyze the molecular structure changes in NR. Based on these results, a possible synergistic effect of thermal oxygen and UV aging mechanisms on NR could be proposed.

This work aimed to study the effect of zinc oxide (ZnO) filler suspension on the mechanical, electrical, and thermal properties of polylactic acid (PLA)/ZnO and cPLA/ZnO. Fused deposition modelling, one of the additive manufacturing methods, was used to fabricate the PLA specimen. PLA was used as the main material in this project, and the ZnO suspension was added during the printing process. The speed of the dispenser (low speed = 1,000 rpm, medium speed = 1,400 rpm, and high speed = 1,800 rpm) was the parameter that was varied to control the filler content of the composite. All the samples underwent a tensile test to determine the mechanical properties, followed by the scanning electron microscopy (SEM) test to analyse the fracture surface properties of the tensile test. SEM observations showed the PLA samples’ inherent smooth appearance, but the PLA/ZnO composite showed a rougher surface. PLA and cPLA composites showed an enhanced storage modulus but lower loss modulus than the pure samples. Because of the high thermal and electrical conductivity of carbon black and ZnO, cPLA composites had higher electrical and thermal conductivity than PLA composites.

This study focuses on investigating the effect of hybrid nanofillers on the hydration characteristics and soil biodegradability of the thermoplastic corn starch (TPCS) hybrid nanofiller biocomposite (TPCS-HB) films. The data were benchmarked with that of the pure TPCS and TPCS single nanofiller biocomposite (TPCS-SB) as control films. The water absorption properties of TPCS, TPCS-SB, and TPCS-HB films were analyzed and fitted with the standard Guggenheim–Anderson–de Boer equation to study the water activity of the films. Besides, the water permeability test, water vapor permeability, and soil biodegradability of the films were also studied and correlated with the films’ surface morphology. The results indicated that the TPCS-HB films possess excellent hydration resistance and comparable biodegradable rate with the TPCS-SB films. The optimal water resistance properties were achieved when the optimal ratio of nanobentonite/nanocellulose (4:1) was incorporated into the TPCS matrix. The outcomes of this study provide an innovative idea and new insights that, by using natural and hybrid nanofillers, the hydrophobicity of the TPCS films could be enhanced. TPCS-HB films show great potential to be developed into a fully green biodegradable TPCS biocomposite film, especially for single-use plastic applications.

The method of set pair analysis was used to evaluate the comprehensive performance of geopolymer mortar (GM) based on metakaolin and fly ash modified by nano-SiO 2 (NS) and polyvinyl alcohol (PVA) fiber, and the design of mix proportion for GM was optimized. According to the experimental results, the addition of the NS and PVA fiber can improve the comprehensive properties of GM. The properties of GM are better when the NS content is 1.5% and PVA fiber content is 0.6%. The comprehensive performance of GM included workability, mechanical properties, fracture properties, and durability, and the typical performance parameters were selected as slump flow, compressive strength, bending strength, fracture energy, loss ratio of compressive strength after cycles of freezing-thawing, and electric flux values. The results show that the weights of each indicator derived from the method of set pair analysis have reduced subjective arbitrariness, improved the evaluation accuracy, and made the conclusions obtained from the set pair analysis method more scientific and reasonable. The method of set pair analysis combines the mechanical properties, durability, and workability of GM blending in PVA fiber and NS to achieve a comprehensive qualitative and quantitative evaluation, which can provide a new method for assessing the comprehensive performance of the GM composites blending in PVA fiber and NS in the future.

Numerous studies have shown that ceramic materials with high dielectric constants and low dielectric losses can be obtained using donor–acceptor-doped TiO 2 . In this study, (La + Nb)-co-doped TiO 2 [(La 0.5 Nb 0.5 ) x Ti 1− x O 2 x -LNTO] ceramic powders were prepared using the sol–gel method. XRD demonstrates that LNTO is a rutile phase, and the lattice parameters change after doping, while X-ray photoelectron spectroscopy explains the doping mechanism, with doping of TiO 2 producing oxygen vacancies and Ti 3+ , which form defective dipoles with the dopant ions to increase the dielectric constant of the material. The dielectric properties were investigated by physically co-blending x -LNTO/polyvinylidene difluoride (PVDF) composites. Compared with the TiO 2 /PVDF composite, the dielectric properties of the x -LNTO/PVDF composite were more excellent. The dielectric constant of 5-LNTO/PVDF reached 36.96, which was higher than that of the TiO 2 /PVDF composite (19.49) at a filler addition of 60 wt% and a frequency of 1 kHz.

The ratio of poly(lactic acid) (PLA), poly(butylene adipate- co -terephthalate) (PBAT), and calcium carbonate (CaCO 3 ) fillers in PLA/PBAT/CaCO 3 composites was set at 90/10/5, 70/30/5, and 30/70/5. The effect of nano- and micro-CaCO 3 on the melting and crystallization performance of the composites was investigated by differential scanning calorimetry. PLA crystallization was related to the PLA and PBAT ratio, cooling rate, and CaCO 3 particle size in PLA/PBAT/CaCO 3 composites. Nano-CaCO 3 prevented the crystallization of PLA in PLA/PBAT/CaCO 3 90/10/5 and 70/30/5 but did not prevent the crystallization of PLA in PLA/PBAT/CaCO 3 30/70/5. Unlike nano-CaCO 3 , micro-CaCO 3 did not prevent PLA crystallization regardless of the PLA and PBAT ratio. Nano- and micro-CaCO 3 enhance PLA90 and PLA70 to some extent, due to the aggregation and dissociation of the CaCO 3 filler in polylactic acid. But nano- and micro-CaCO 3 improved the mechanical properties of PLA30 several times, due to the good compatibility of the CaCO 3 filler and PBAT. The effect of nano-CaCO 3 and micro-CaCO 3 on the mechanical properties of PLA/PBAT/CaCO 3 composites had no significant difference.

Damage to polymer adhesives is one of the most common reasons for structural integrity damage of composite solid propellants. The introduction of self-repairing technology into the adhesive is expected to solve this problem. However, at low temperatures, the self-repairing and mechanical properties of the materials are greatly impaired, thereby limiting the application of self-repairing adhesives in composite solid propellants. In this study, based on the dual synergistic crosslinking strategy, a polyurethane adhesive exhibiting excellent self-healing and mechanical properties at low temperatures was successfully prepared. The adhesive exhibited high self-repairing efficiency and ultra-long elongation at break at low temperatures. Specifically, at a low temperature of −40°C, the self-repair efficiency was over 70% and the elongation at break was over 1,400%, which were much higher than the results of the control group. Moreover, the strength was comparable to that of the control group. This polyurethane adhesive shows excellent self-healing and mechanical properties at low temperatures and is expected to provide the strong self-healing ability and mechanical properties for composite solid propellants, alleviating the problem of structural integrity damage. Graphical abstract A self-healable HEPU-Zn polyurethane adhesive was prepared. Through the dual synergetic crosslinking strategy, HEPU-Zn was endowed with excellent mechanical and self-healing properties at low temperatures.

This article describes the synthesis of polyesteramide (PEA) resin from Leucaena leucocephala oil (LLO) obtained from seeds of L. leucocephala tree, locally grown in King Saud University Campus. LLO was transformed into amide diol by based catalyzed amidation reaction, followed by esterification reaction with malic acid (MA), that resulted in LLO-based PEA (LPEA). The synthesis was performed without using any solvent or catalyst. Fourier-transformation infrared spectroscopy and nuclear magnetic resonance confirmed the formation of LPEA by the introduction of amide and ester moieties. LPEA was further reinforced with nano graphene oxide (GO) and fabricated into nanocomposite corrosion protective coatings (LPEA/GO). LPEA/GO coatings obtained were tough, flexibility retentive and showed good corrosion resistance performance toward 3.5 w/w% NaCl medium. Thermogravimetric analysis confirmed good thermal stability of coatings with safe usage up to 200°C.

UF-SiAPP was prepared by modifying ammonium polyphosphate with the urea formaldehyde resin (UF), tetraethylorthosilicate (TEOS), and vinyltriethoxysilane (A-151). Moreover, a new intumescent flame retardant (IFR) used for low density polyethylene (LDPE) flame retardant was obtained by mixing UF-SiAPP with tris(2-hydroxyethyl) isocynurate (THEIC). The structure, morphology, and mechanical properties of flame retardants and LDPE composites were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, TG, and universal material testing machines. Furthermore, the flame-retardant properties of LDPE composites were comprehensively investigated by limiting oxygen index (LOI), UL-94, and cone calorimetry tests. The results show that UF-SiAPP exhibits excellent hydrophobic properties and good compatibility with LDPE after being modified by UF, TEOS, and A-151. And the flame-retardant properties of LDPE composites are significantly improved by adding IFR-containing UF-SiAPP. Especially, the LDPE composites attained the LOI value of 30.5% and reached the V-0 level after introducing 20.0 wt% UF-SiAPP and 10.0 wt% THEIC. And the tensile strength reached 13.55 MPa, which was 10.33% higher than that of LDPE/IFR with UF-APP and 13.21% higher than that of LDPE/IFR without THEIC in the same proportion. The smoke density tests demonstrate that the addition of UF-SiAPP not only effectively improves the residual carbon content and thermal stability of LDPE composites but also significantly reduces smoke emissions.

The series of double network (DN) hydrogels, based on poly( N,N ′-diethylacrylamide) (PDEAAm), polyacrylamide (PAAm), or poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS) were synthesized with various mass ratios of components and their thermal response was investigated. The formation of DN structure in studied hydrogels results in significant increase in Young’s modulus. PDEAAm/PAMPS hydrogels exhibited rather high swelling ratio and consequently their temperature sensitivity was not detected. DN hydrogels PDEAAm/PAAm and PDEAAm/PDEAAm displayed thermo-responsive behavior, and the dependence of transition parameters on the feed molar concentration of acrylamide and N,N ′-diethylacrylamide monomers, respectively, was determined through deswelling, NMR, and Differential scanning calorimetry (DSC) experiments. A two-state process model was employed to describe the phase transition of hydrogels. By utilizing a modified van’t Hoff equation with data from deswelling, NMR, and DSC experiments, we were able to obtain thermodynamic parameters of the transition and determine the size of the cooperative domains consisting of polymer units and water molecules.

This research focuses on recycling rubber tire waste through pyrolysis to produce recovered carbon black (rCB). The rCB is combined with recycled low-density polyethylene (rLDPE), calcium carbonate (CaCO 3 ), fatty acid, metallic stearate, and polyethylene (PE) wax to create an rCB masterbatch for household packaging. Surface modification of CaCO 3 particles using stearic acid improves the compatibility with LDPE. The study investigates mechanical properties, morphology, melt flow index (MFI), X-ray diffraction, and thermogravimetric analysis in three systems: uncoated, coated, and a hybrid combination of coated and uncoated CaCO 3 in LDPE/rCB masterbatch composites. The coated system demonstrates higher mechanical properties and improved compatibility between CaCO 3 and LDPE. All three systems exhibit enhanced thermal stability and MFI compared to virgin LDPE, with the coated system showing the most significant improvement. The study showcases the potential of LDPE/rCB masterbatch composites for household packaging, with the coated system displaying the optimum performance across various characteristics.

The study of repairing materials is of paramount importance, considering that damage during usage can significantly impact performance and bring inconvenience during maintenance work. One highly sought-after material is water-swellable elastomers, known for their effect in sealing and repairing damaged materials. In this study, agar/polyurethane dual-network hydrogel elastomers were prepared, which were further modified by MXene. The material exhibits a uniform and flat surface, along with a rich pore-filled internal structure. It showcases excellent thermal stability, good tensile strength retention, and a controllable low swelling rate (SR) upon water absorption. The performance of the material can be regulated by the MXene content. In addition, the “water absorption–drying–water absorption” cycle effectively controls the reduction of the SR and gradually increases the tensile strength. All samples demonstrated exceptional photothermal conversion efficiency, stability, and durability, with the maximum conversion temperature increasing with the MXene content. The scratch repair experiments demonstrated the remarkable potential of these materials for photothermal conversion-assisted repair. These materials can be adapted as auxiliary restoration materials in water bodies and various application environments, making them ideal for repair and restoration purposes.

Piezoelectric damping composites with excellent damping properties were prepared from carbon black (CB), lead magnesium niobate (PMN), epoxy resin, and polyether amine D-400. The tan δ {\rm{\tan }}\delta area (TA) analysis method is used to evaluate the leading factors of damping enhancement. This method clearly shows the influence of the maximum loss factor ( tan δ {\rm{\tan }}\delta max ) and effective damping temperature range on damping performance, and the damping enhancement factors are quantitatively analyzed by TA values. When CB content is less than 8 wt%, viscoelastic damping and frictional energy dissipation are the main factors affecting polymer properties. When CB content reaches 8 wt%, the conductive network gradually forms, and the electric energy generated by PMN through the piezoelectric effect is dissipated by the conductive network, and the piezoelectric effect of PMN becomes the dominant factor. In this case, the maximum tan δ \tan \delta max and TA values of the composite are 1.93 and 27.58, respectively. The damping contribution of PMN and CB reaches 40.21% and 34.41%, respectively.

Four energetic binders, polyglycidyl nitrate (PGN), poly(3-nitratomethyl-3-methyloxetane) (PNIMMO), poly(bis(azidomethyl)oxetane) (PBAMO), and glycidyl azide polymer (GAP) were, respectively, mixed with dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate (TKX-50), forming TKX-50-based polymer bonded explosives (PBXs). Interfacial forces (binding energies) under different temperatures, mechanical properties (tensile modulus, bulk modulus, shear modulus, and Poisson’s ratio), and moldability of TKX-50-based PBXs were investigated by employing molecular dynamics simulation, the energy characteristics of TKX-50-based PBXs were calculated by Chapman–Jouguet (C–J) detonated theory. Results show that temperature has little effect on the binding energies, but the binding energies between every energetic binder and each surface of TKX-50 are different and the order of combined ability between four energetic binders and TKX-50 decrease as follows: PNIMMO > PBAMO > PGN > GAP. Compared with TKX-50, the addition of four energetic binders makes the rigidity of TKX-50-based PBXs decrease and the plasticity improve, the plastic ability rank is in the order of PGN > PNIMMO > PBAMO > GAP. In addition, the moldability of TKX-50-based PBXs is obviously improved, the increasing order is PGN > PNIMMO > PBAMO > GAP. Finally, the detonation performances indicate that compared with common binder, the addition of the energetic binder makes TKX-50-based PBXs have higher energy under the same condition.

In this work, untreated/treated sisal fibre (SF)-reinforced sodium alginate composites for three different concentrations (1.5%, 2%, and 2.5%) are fabricated by the hand lay-up method, and the variations in mechanical properties such as tensile strength, flexural strength, and impact strength are studied. The treated and untreated composites are analysed and compared using scanning electron microscope to study the surface morphology. Energy-dispersive spectroscopic analysis is carried out to evaluate the elemental compositions. Fourier transform infrared spectroscopic analysis is conducted to determine the interaction between fibres and matrix material. The thermal observations such as differential scanning calorimetry and thermogravimetric analysis showed only slight variations between the untreated and treated SF composites. The results of this work indicate that untreated sample with the maximum sodium alginate gum concentration had significantly enhanced mechanical properties and low moisture absorption rate. Biodegradation test inferred that it was superior for the treated fibre rather than the untreated fibre composites. The primary objective of this work is to assess the suitability of these composites for non-structural engineering applications.

In the production of powder-coating polyester, a strong odor emanates from the water, prompting us to investigate its composition and origin. We studied the process of powder coating epoxy/polyester 50/50, which employs butyl tin tris (2-ethyl hexanoate) as a catalyst. The esterified water was extracted using ethyl acetate. It was analyzed via GC–MS to identify the side reactions and by-products that arise during the tin-catalyzed esterification process. Then we discussed their formation mechanism. Our results indicate that butyl tin tris (2-ethyl hexanoate) triggers side reactions such as cyclization and transesterification, leading to the production of by-products such as heterocyclic compounds (1,4-dioxane), anhydride compounds (propionic anhydride), and others. Notably, the unpleasant odor was found to be derived from propionic anhydride. These findings provide insights into the chemistry of tin-catalyzed esterification and highlight the importance of addressing the formation of unwanted by-products in the production of powder-coating polyester.

Oil-impregnated paper is the most widely used insulating material for power transformers. Power transformers inevitably generate a lot of heat during operation. Among them, thermal aging is one of the main forms of aging for insulating paper. In this study, the ab initio molecular dynamics method based on the density functional theory is used to simulate the cracking mechanism of cellobiose under transient high temperature. The results show that the cellobiose is relatively stable at 343 K, the motility of the cellobiose is enhanced at 1,800 K, the cellobiose starts to decompose at 2,400 K, and new characteristic products are formed at 3,000 K. The characteristic products include CO, H 2 O, CH 3 OH, H 2 , and CH 4 . These characteristic products can represent the degree of cracking of insulating paper. Therefore, it is necessary to explore the mechanism of cracking of insulating paper caused by transient high temperature.

Heat stabilizers are crucial additives for enhancing the thermal stability of polyvinyl chloride (PVC) during processing. Among the various heat stabilizers available, organic tin compounds have shown remarkable effectiveness. In this study, we investigated the use of dimethyltin dineodecanoate (DMTDN), dibutyltin dineodecanoate (DBTDN), and dioctyltin dineodecanoate (DOTDN) as heat stabilizers for PVC. These compounds were combined with calcium stearate (CaSt 2 ) and zinc stearate (ZnSt 2 ) to improve the thermal stability of PVC materials. The results demonstrated that the thermal stabilization effects of the three tin neodecanoates, when used as standalone heat stabilizers, followed the order: DOTDN > DBTDN > DMTDN. Notably, the thermal stability and lubricity of the three-component heat stabilizer (MTN 5 -C 4 Z 1 , BTN 5 -C 4 Z 1 , and OTN 5 -C 4 Z 1 , respectively), which consisted of the three types of tin neodecanoate, CaSt 2 , and ZnSt 2 in a ratio of 5:4:1, outperformed the use of tin neodecanoate alone. This study offered potential formulations to reduce the application cost of tin neodecanoate as a PVC heat stabilizer.

The use of natural polysaccharides in stretchable hydrogels has attracted more and more attention. However, pure polyvinyl alcohol (PVA) hydrogel has poor mechanical properties and low sensitivity in strain sensors. Composite hydrogels with high tensile properties (the storage modulus of 6,397.8 Pa and the loss modulus of 3,283.9 Pa) and high electrical conductivity (1.57 S·m −1 ) were prepared using a simple method. The Fe-vermiculite and lignocellulosic nanofibril-based hydrogels were applied as reliable and stable strain sensors that are responsive to environmental stimuli. The prepared hydrogels exhibited excellent ionic conductivity, which satisfied the needs of wrist flexion activity monitoring. The results showed that the PVA/LF 0.4 hydrogel has a natural formulation, high mechanical strength, and electrical conductivity, which has great potential for application in artificial electronics. Graphical abstract Schematic illustration of the fabrication of the PVA/LF 0.4 hydrogel, which is then used as conductive hydrogel in electron skin sensors due to excellently tensile (596.7%) and highly conductive (1.57 S‧m −1 ) properties.

A series of polyepoxide resins doped by lead oxide with low concentrations were fabricated in order to study the impacts of low PbO concentrations on the fabricated composites’ physical- and radiation-shielding properties. The epoxide resin was reinforced with the PbO compound with concentrations 0, 5, and 10 wt%. The density measurements affirmed that by elevating the PbO concentration between 0 and 10 wt%, the composites’ density increased from 1.103 to 1.185 g·cm −3 . This low-density increase was echoed in the fabricated composites’ radiation-shielding properties, where the Monte Carlo simulation code affirmed a linear attenuation coefficient increase by factors of 230%, 218%, 24%, and 10%, respectively, at 59, 121, 356, and 662 keV. The half-value layer, mean free path, and transmission factor indicated a linear attenuation coefficient enhancement.

The structure of antioxidants significantly affects the anti-migration and thermal-oxidative aging properties of nitrile butadiene rubber (NBR) composites, which are crucial for applications in aerospace, biomedical, and fuel cell stack sealing industries. The findings reveal that the migration rate of N -(4-anilino phenyl) maleic imide (MC), with a reactive double bond, is only 15.6%, exhibiting the best extraction resistance. 2,4,6-Tris-( N -1,4-dimethylpentyl- p -phenylenediamino)-1,3,5-triazine (TMPPD), with a greater weight and dendritic structure, follows at 47.7%, while N -isopropyl- N ′-phenyl- p -phenylenediamine (4010NA) performs the worst, with 77.8%. Furthermore, after thermal-oxidative exposure, the cross-link density of NBR composites increases, generating oxygenated substances, such as ethers, aldehydes, and acids. The addition of antioxidants in the composites improves the thermal-oxidative aging properties compared to those without any antioxidants. Moreover, antioxidants 4010NA and TMPPD display superior resistance to thermal-oxidative aging properties compared to antioxidant MC.

Polyvinyl alcohol (PVA) hydrogels have been extensively investigated for drug release, artificial cartilage, biosensing, and other applications owing to their good chemical stability, biocompatibility, high water absorption, and ease of processing. However, the conventional hydrogel preparation method is complex and energy-intensive, and the mechanical performance of the pure PVA hydrogel is poor, which severely limits its application in related fields. In this study, a PVA hydrogel was functionally modified using polybutylene succinate (PBS) nanofibers prepared using in situ fiber-forming technology to fabricate a PBS-enhanced PVA composite hydrogel. The strength of the PBS/PVA hydrogel fabricated in this study is 3.88 MPa, which is 4.94 times that of the pure PVA hydrogel; thus, the strength of the hydrogel was effectively improved. The hydrogel preparation method used in this study is novel and straightforward. Moreover, the resulting materials are biodegradable and non-toxic. Compared to conventional methods, this method has the advantages of conserving resources and being environmentally friendly.

A novel homogenous braid-reinforced (HBR) poly ( p -phenylene terephthamide) (PPTA) hollow fiber membrane was prepared in this study. The effects of PPTA concentration on the morphologies and properties of the membranes were further investigated. The results showed that when the PPTA concentration was 2.0 wt%, the cross-sectional morphology of satisfactory interfacial bonding was achieved and the permeation was still maintained at about 200 (L·m −2 ·h −1 ) after ultrasonic vibration. In addition, the tensile force exceeded 600 N, which indicated that the homogeneous effect effectively improved the poor mechanical properties and interfacial bonding. In addition, the HBR PPTA hollow fiber membranes were applied to simulate the membrane bioreactor system to explore the control factors of membrane fouling. The results demonstrated that the average removal of total phosphorus and NH 4 + –N was above 49% and 96%, respectively; meanwhile, the operating time was up to 120 days. Furthermore, it was easier to nearly remove the pollutants by chemical cleaning.

Cd( ii ) ion was used as template ion, and N , N '-pyridine-2,6-di(2-methacrylamide) was used as the functional monomer. The experimental conditions for the synthesis of Cd( ii ) ion-imprinted composite membranes (Cd( ii )-IICMs) were optimized by the surface-imprinting method, and 25 Cd( ii )-IICM 1–25 and their corresponding non-imprinted composite membranes (NICM 1–25 ) were prepared. Then, the structures of the optimal membranes Cd( ii )-IICM 17 and NICM 17 were characterized by scanning electron microscopy, Brunner–Emmett–Teller, thermogravimetric analysis, contact angle analysis, and the effects of different adsorption conditions were studied. The adsorption behavior was analyzed by isothermal adsorption models and kinetic models. The permeation selectivity of Cd( ii )-IICM 17 towards Cd( ii ) ions was studied. Results of the experiment indicate that Cd( ii )-IICM 17 had excellent adsorption properties for Cd( ii ) ions with an imprinting factor of 2.15. The adsorption of Cd( ii ) ions in solution by Cd( ii )-IICM 17 and NICM 17 was in accordance with the Freundlich isothermal adsorption model and the pseudo-second-order kinetic model. In addition, in the presence of the competing ions Co( ii ), Ni( ii ), and Cu( ii ), Cd( ii )-IICM 17 showed good permeation selectivity for Cd( ii ) ions, and the permeation process followed a facilitated permeation mass-transfer mechanism. In summary, the Cd( ii )-IICM 17 prepared in this study has good application prospects for the separation and removal of Cd( ii ) ions from wastewater.

In this study, we developed flexible composites using silicone rubber (SR) or polydimethylsiloxane as the matrix and WO 3 and BaO nanoparticles as filler to analyze their radiation-shielding performance. The linear attenuation coefficient (LAC) values for the prepared composites were reported to range from 0.059 to 1.333 MeV by using the experimental method. At 0.059 MeV, the SR with 40% of BaO NPs possesses the highest LAC, followed by SR with 20% of BaO and WO 3 NPs. The SRs S-2 and S-4 that contain WO 3 and/or BaO exhibit continuously greater LAC values than the sample S-1. Numerically, the LAC for S-2 (with 40% of BaO NPs) is 1.6 times greater than that for S-1 (free BaO and WO 3 ) at 0.662 MeV, while the LAC for S-2 is 1.47 times more than that for S-1 at 1.275 MeV. We examined the impact of the thickness of the prepared composites on the attenuation performance by studying the transmission factor (TF) at two different thicknesses (1 and 2 cm). For S-1 and S-2, the TF decreases due to the increase of the thickness from 1 to 2 cm. The TF for S-1 with a thickness of 1 cm is 75% at 0.059 MeV, while it is 56% (for 2 cm). We evaluated the percentage decrease in the TF at 0.059 MeV for every SR as the thickness changes from 1 to 2 cm. For S-3, S-4, S-5, and S-6, the percentage decrease in the TF is extremely significant varying from 98% to 99%. This suggests that increasing the thickness of these SR samples from 1 to 2 cm has a major effect on the shielding capabilities they possess, particularly at low energies.

Radiation and nuclear technologies have side effects in addition to their important applications, so appropriate shields must be used to protect users and the public from high doses as a result of exposure to this radiation. In this work, the attenuation coefficients for polyester composites doped with waste iron filings (IFs) were studied. Six samples of different IF concentrations were manufactured, namely, Poly, Poly-IF20, Poly-IF30, Poly-IF40, Poly-IF50, and Poly-IF60 (where Poly-IF60 represents 40% polyester and 60% IF). We measured the attenuation factors using high purity germanium (HPGe)-detector along with three radioactive sources 241 Am (emitting energy of 0.06 MeV), 137 Cs (emitting energy of 0.662 MeV), and Co-60 (emitting energy of 1.173 and 1.333 MeV). We compared the linear attenuation coefficient (LAC) obtained by theoretical (i.e., XCOM software) and experimental (i.e., HPGe-detector) approaches for the prepared polyester composites at various photon energies (0.060, 0.662, 1.173, and 1.333 MeV). The greatest difference between the LAC values of the samples occurs at 0.060 MeV, where the Poly-IF60 sample has a much greater LAC than the other shields, followed by the Poly-IF50 sample, Poly-IF40 sample, and so on until the pure polyester shield. Specifically, their values are equal to 0.245, 0.622, 0.873, 1.187, 1.591, and 2.129 cm −1 for Poly, Poly-IF20, Poly-IF30, Poly-IF40, Poly-IF50, and Poly-IF60, respectively. We calculated the transmission factor (TF) and the radiation shielding efficiency (RSE), and found that the TF for Poly-IF30 is equal to 28.82%, 77.94%, 82.75%, and 83.75% at 0.060, 0.662, 1.173, and 1.333, respectively, while its RSE is equal to 82.57%, 24.00%, 18.80%, and 17.72%, respectively. The fast neutron removal cross-section (FNRC) of the polyester samples was calculated and the values increase when more Ifs are added to the samples. More specifically, the FNRC values are equal to 0.095, 0.100, 0.103, 0.107, 0.110, and 0.113 cm −1 for Poly, Poly-IF20, Poly-IF30, Poly-IF40, Poly-IF50, and Poly-IF60, respectively.

This research aimed to prepare and characterize a new type of polymeric cross-linked topical hydrogel patches for the treatment of wound infections. The free radical polymerization method was used to prepare the topical hydrogel patches by utilizing natural polymers, i.e., agarose and gelatin. These natural polymers were chemically cross-linked with monomer (acrylic acid) using ammonium persulfate as an initiator via the cross-linker N , N methylene bisacrylamide. An antibiotic, i.e., gentamicin sulfate was loaded into a designed polymeric system. The polymeric cross-linked topical hydrogel patches were made in a spherical shape, which was revealed to be stable and elastic. Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and X-ray powder diffraction investigation were used to characterize the topical hydrogel patches. Polymeric cross-linked hydrogel patches were evaluated for their sol–gel analysis, swelling studies, in vitro drug release studies against pH 5.5, 6.5, and 7.4, ex vivo drug permeation, and the deposition study on the rabbit’s skin by using a Franz diffusion cell. In addition, the skin irritation study and wound healing performance of drug-loaded topical patches were also assessed and compared to commercially available formulations. The topical hydrogel patches were found to be non-irritating to the skin for up to 72 h as determined by a Draize patch test and when compared to marketed formulations, these topical patches resulted in faster wound healing. The prepared formulation showed promising potential for the treatment of skin wound infection.

Homogenization of pigment is the key to coloring a plastic product evenly. In this article, the tensile properties of recovered carbon black merge with low molecular weight lubricants and other compounding ingredients in the form of pigment masterbatch (PM) added in a recycled low-density polyethylene (rLDPE) resin were evaluated. The prepared masterbatch with the varying amount and types of processing aids (A and B) was first compounded using the heated two-roll mill. Subsequently, the manually mixed masterbatch in rLDPE was put through an injection molding machine for the shaping process to produce an rLDPE pigment masterbatch composite (PMC). The tensile test was performed on the samples to evaluate the mechanical properties of the PMC. Meanwhile, the melt flow index test was executed to justify the composite flow characteristics. Fourier-transform infrared spectroscopy analysis and scanning electron microscopy were also carried out to analyze the PM and PMC chemical properties and their constructed surface morphology. Besides, X-ray diffraction analysis was performed to determine the changes in degree of crystallinity before and after the water absorption test. The addition of PM in rLDPE has slightly increased the rLDPE matrix tensile properties. While, the usage of more processing aid B in the PMC has turned out to secure better tensile properties compared to the addition of higher amount of processing aid A in the PMC. Interestingly, the tensile properties of all composites after the water absorption test were enhanced, suggesting that a stronger bond was formed during the immersion period.

Natural fibre composites are widespread for being eco-friendly and having unique properties. This study prepared nanocomposites by water evaporation using cellulose nanofibres (CNFs) as fillers and natural rubber (NR) latex as the matrix. Here, CNFs were extracted from the “pineapple fruit residue,” a waste material in juice industries. These fibre-reinforced nanocomposites were prepared under three different weight/volume percentages (5%, 10%, and 15%) and analysed for their mechanical and thermal properties. Furthermore, the morphology and distribution of CNFs in the NR matrix were examined by scanning electron microscopy and Fourier transform-infrared (FT-IR) analysis. The study found that CNFs were randomly oriented and evenly distributed in the nanocomposite. CNFs were detected by FT-IR spectroscopy in the NR matrix, as indicated by absorption peaks at 1,033 and 1,057 cm −1 . Thermogravimetric analysis reveals increased thermal stability with more CNFs. Tensile strength and elastic modulus also increase. Pineapple fruit residue-based CNFs enhance mechanical and thermal properties of NR composites and can be considered an ideal natural reinforcing material.

In this study, Indocalamus micro/nanofibers (IMFs) were extracted from natural Indocalamus leaves by physical processing and alkaline treatment. IMFs reinforced epoxy resin (EP) and their carbon-fiber composites (IMFs/CFRP) were fabricated. The effects of IMF on the mechanical properties of the EP and CFRP composites were studied. Infrared spectroscopy and scanning electron microscopy (SEM) were used to characterize the functional groups and microstructure of IMF, EP, and CFRP. The experimental results showed that the strength of the EP increased as the IMF content increased from 0% to 20%, but on further increase in IMF content of 25%, the strength of the EP reduced. In addition, the mechanical properties of the IMF/CFRP were slightly higher as compared with the control CFRP. The SEM observations on IMFs/EP and IMFs/CFRP composites reveal that the alkali-treated IMFs facilitate the interfacial interlocking structure and improve the interfacial adhesion of the composites.

Energy-saving tires have been developed by researchers in the industry in order to minimize hysteresis loss. In general, this is achieved by combining precipitated silica sourced from silica sand with a silane coupling agent. This strategic reaction serves to elevate the performance characteristics of tread tire, effectively enhancing their properties. Therefore, this research is aimed to investigate the utilization of commercially available biosilica compared to high dispersed (HD) silica, examining their potential as reinforcing agents in the composition of passenger tread tire compound. This compound was formulated using a blend of solution styrene-butadiene rubber (SSBR) and butadiene rubber (BR). A comprehensive analysis was conducted to assess the impact of varying ratios between biosilica and HD silica on the mechanical and dynamic properties of tread tire compound composed of SSBR and BR blend. The results showed that the incorporation of biosilica could effectively reduce the filler network resulting in better dispersion of biosilica in the SSBR/BR blend matrix. As a result, it improved wet grip (44%) and rolling resistance (26%) while maintaining abrasion resistance compared with HD silica in passenger tread tire compound. The application of biosilica as an eco-friendly reinforcement material exhibited its potential for elevating the performance of energy-efficient tread tire.

Multi-layer micro-capillary films (MCFs) have broad application prospects in the micro-fluid field. These films consist of two-dimensional arrays of hollow microcapillaries. The arrangements of hollow microcapillary arrays in extrusion die strongly influence the shape and size of multi-layer MCFs. However, most of the studies focus on a single-layer film. In this study, the models of multi-layer MCF extrusion die with hollow capillary arrays from one layer to four layers have been modeled. Numerical simulations show that when the hollow capillary arrays in different layers are aligned, the aspect ratio of the capillary is smaller and the flow resistance is small, so this kind of multi-layer MCF is suitable for micro-reactor and melt pump. When the hollow capillary arrays in different layers are non-aligned, the aspect ratio of the capillary is relatively larger and the specific surface is bigger, so this kind of multi-layer MCF has a high capability of heat exchange and is suitable for micro heat exchangers.

This study presents a method for producing microfluidic chips from polypropylene using a pre-heated bonding area and thermal bonding technology. ANSYS was utilized to investigate the effects of bonding parameters and microchannel deformation and predict the bonding strength. Results show that careful control of these parameters is critical to achieve a strong and durable bond between the microfluidic chip layers. Higher bonding temperatures were found to lead to greater microchannel deformation, with deformation increasing significantly, as the temperature approached the material’s melting point. Increased bonding pressure after 1 MPa and a time of 300 s also led to greater microchannel deformation. The study’s analysis of stresses revealed that the maximum principle compressive stress on the edges of the bonding area increased significantly with pressure. Tensile testing showed that bonding strength was near failure at a tensile force of 5,500 N, indicating a bonding strength close to 1.5 MPa.

The objective of this study is to explore the impact of a nanofiller, hexagonal boron nitride (h-BN), on the main physical, electrical, and thermal characteristics of unsaturated polyester (UPE) resin. To obtain a homogeneous dispersion, h-BN nanoparticles were surface-modified using 3-glycidoxypropyltrimethoxysilane to give S/h-BN nanoparticles. UPE-S/h-BN composites were prepared by using various ratios (1, 5, 10 wt%) of these modified nanoparticles. Thermogravimetric analysis studies showed that the presence of S/h-BN nanoparticles boosted the thermal stability of the UPE resin. The electrical volume resistivity value increased from 1.3 × 10 13 to 1.38 × 10 14  Ω cm with the addition of 10 wt% S/h-BN. The contact angle results indicated that the hydrophobicity of UPE-S/h-BN composites increased and the value of 110° was obtained for UPE-S/h-BN10. The findings revealed that incorporating S/h-BN nanoparticles into UPE resin, in specific ratios, improved its properties and the resulting product has the potential to be used as an insulation varnish.

A series of aliphatic amine-functionalized multiwalled carbon nanotubes (MWCNTs) wherein varied secondary amine numbers were grafted on the MWCNTs’ surface were synthesized and further dispersed onto the glass fibers for reinforcing epoxy-based composites. By tuning secondary amine numbers of aliphatic amines, the dispersion of MWCNTs and ultimately mechanical, thermal, and conductive properties of epoxy-based composites could be adjusted. Using an optimal secondary amine number of aliphatic amine (triethylenetetramine), the interlaminar shear strength, tensile strength, and flexural strength of epoxy-based composite increased by 43.9%, 34.8%, and 35.0%, respectively; the work of fracture after interlaminar shear tests increased by 233.9%, suggesting strengthening/toughening effects of functionalized MWCNTs; significant reduction in surface resistance and increased thermal conductivity were also obtained, implying the superior conductive properties for composites. This work offers a new strategy for designing fiber-reinforced composites with high strength, excellent antistatic properties, and good thermal conductivity for medical device applications.

In this study, we aimed to reveal the effective reusability of waste generated during the injection molding process of polyamide 66 (PA66) reinforced with 30 wt% of short glass fiber (PA66-GF30) widely used in the automotive industry. PA66-GF30 was subjected to the three mechanical recycling cycles, including regranulation and reinjection molding steps, and the recycled materials obtained in each of these cycles were included at the ratios of 15, 20, 25, and 30 wt% to the virgin composite. Thermogravimetric analysis and differential scanning calorimeter analyses showed that the number of recycling cycles and recycled material content in the composite had no significant change in the thermal stability and crystallinity degree of the PA66-GF30. The average fiber length determined by optical microscope analysis shifted to lower values from 300–350 to 150–250 μm by increasing the number of recycling cycles and the recycled material content. The fact that the recycled material content in the composite exceeds 25 wt% and the recycling cycle is applied three times played a key role in changing the mechanical and melt flow behaviors of the composite. Tensile strength, elastic modulus, and impact energy slightly decreased while the elongation at break and melt flow index increased.

This study deals with the preparation and characterization of novel composites accomplished by filling hydroxyethylcellulose with several amounts of bentonite. Molecular modeling enabled understanding the conformational and physicochemical features, which are responsible for the chemical reactivity parameters. Rheological analyses are made to investigate the effect of the polymer loading on the shear flow behavior. The morphology and homogeneity of each system is explored via optical microscopy. The band gap of the samples is slightly reduced by the addition of the bio-filler in the cellulosic medium, as indicated by UV-VIS spectral data. The dielectric response of these materials is extracted from refractometry experiments at several wavelengths. The electric energy density was achieved based on the dielectric properties determined at high and low frequencies. The outcome of this study offers new ways to produce alternative dielectric eco-materials having a good potential of accumulating electrical energy, as demanded for capacitor devices.

Polyphenylene sulfide (PPS) and copper (Cu) were used as the polymer and substrate material to simulate the nano-injection molding process by molecular dynamics method. The results show that the PPS chain obeys Einstein’s diffusion law in the early stage of injection molding then deviates from it in the late stage due to the entanglement and limitation of surrounding nanoparticles. In addition, the process of conformational isomerization of polymer chains is accompanied by the twisting and stretching of fixed chains. There are two kinds of adhesion phenomena, one is the macromolecular slides violently in small areas of some sure nanoscale groove to form multiple anchor points. The other case involves multiple nano-grooves along the metal interface, the polymer chain slides and is bolted as multiple anchors in different grooves due to the exerted wall-drag effect on the neighboring chains. These two slipping and anchoring mechanisms are consistent with de Gennes’ slipping theory. Through the quantitative analysis of the influence of pressure on injection filling, it is found that injection pressure should be kept within a certain range to achieve the positive effect of molding.

The objective of this research is to develop an unsaturated polyester (UPE) varnish with low-volatile organic compounds (VOCs). Instead of using a solvent, the solvent-free varnish incorporates a reactive diluent to reduce viscosity and a catalyst to accelerate curing. To achieve this, vinyl toluene and 1,4-butanediol dimethacrylate were employed as curing agents. Sebacic acid (SA) and fumaric acid were utilized to create UPE coatings for electrical insulation. Various tests and measurements were made to evaluate the physical, thermal, and chemical structure determination, and electrical properties of the synthesized resins. Given the increasing demand for eco-friendly and low-VOC products, gas chromatography was employed to determine VOC levels. The study demonstrated that the electrical volume resistance of cross-linked coatings containing FA was 1.58 × 10 15  Ω·cm, whereas coatings containing SA exhibited a measurement of 6.96 × 10 11  Ω·cm. VOC levels in the UPE coatings were found to be in the range of 2.10–3.60%.

In this study, chlorogenic acid nanoparticles encapsulated in Pluronic F127 polymer were synthesized and characterized to determine if they could treat human liver cancer. The nanoparticles were synthesized using standard procedures and characterized using physical and biological techniques such as X-ray diffraction, Fourier transform infrared spectroscopy, UV-Vis, dynamic light scattering, Photoluminescence, scanning electron microscopy, and transmission electron microscopy. The anticancer effects were assessed using MTT analysis, acridine orange/ethidium bromide, reactive oxygen species (ROS), COMET assay, annexin-V/FITC, cell cycle analysis, and expression of marker genes against HepG2 cell lines. The results showed significant cytotoxicity, apoptosis induction, and increased ROS production in treated cells compared to control cells. The nanoparticles also activated the apoptotic cascade and regulated the PI3K/AKT/mTOR pathways. The nanocomposites exhibited unique characteristics such as anticancer efficacy in vitro . Further research was conducted using zebrafish to model hematological parameters, liver enzymes, and histopathology to study effectiveness. Green-synthesized Pluronic F127–chlorogenic acid nanoparticles can be considered potential cancer therapy agents.

Herein, the performance of silicone-modified 3D printing photosensitive resin was examined. Bisphenol-A epoxy acrylate (EA) was used as the substrate and isophorone diisocyanate, hydroxy-silicone oil, and hydroxyethyl acrylate were used as the raw materials. A silicone intermediate was synthesized to modify the substrate to prepare the 3D printing photosensitive material. The as-synthesized materials were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. The tensile fracture morphology was also analyzed. The effects of the addition of silicone intermediates on the mechanical properties, thermal stability, and shrinkage of the prepared 3D printing photosensitive resins were investigated. The results showed that an organosilicone group was successfully introduced into the side chain of EA. When the ratio of n (silicone): n (EA) is 0.3:1, the material has a high impact strength of 19.4 kJ·m −2 , which is 32.8% higher than that of the pure resin; in addition, the elongation at break is 8.65% (compared to 6.56% of the pure resin). The maximum thermal weight loss temperature is 430.33°C, which is 6°C higher than that of the pure resin.

A novel and simple way for efficiently preparing stable and non-toxic slippery lubricant-infused porous surface (SLIPS) will expand its anti-fouling and anti-corrosion applications in marine environments. Herein, vinyl-terminated polydimethylsiloxane was covalently grafted on the surface of nano-SiO 2 by a thiol-ene click chemistry reaction. After that, SLIPS was efficiently prepared at room temperature via the spraying method on various substrate surfaces. Surface wettability results showed that a water droplet (10 μL) can slip on the surface with an inclination of 10° and a stained water droplet can slip without stain during the slide process, which proved that SLIPS displayed excellent slippery performance. The existence of molecular-level slippery silicone oil film on the rough surface. Anti-fouling and anti-corrosion tests showed that the prepared SLIPS exhibited stable and excellent anti-fouling and anti-corrosion performance after immersion in Pseudoalteromonas sp. culture solution for 14 days. The SLIPS exhibited a value of more than 98% of bacterial attachment inhibition efficiency and a value of 99.9% of corrosion inhibition efficiency. This facile method provides guidance to fabricate SLIPS for its anti-fouling and anti-corrosion applications in marine environments. Graphical abstract

This research study’s objective was to formulate interpenetrating pH-sensitive polymeric networks interpenetrating networks (IPNs) based on hydroxypropylmethylcellulose (HPMC)/Primojel for use in the treatment of various malignant conditions. For controlled release, letrozole (LTZ) was selected as a model drug in HPMC and Primojel-based IPN hydrogels. HPMC and Primojel based IPN hydrogels were fabricated through the free radical polymerization method by utilizing HPMC and Primojel as polymers, methacrylic acid as monomer, ammonium persulfate as initiator, and methylenebisacrylamide as cross-linker. For structural characterization, various techniques such as Fourier transform infrared spectroscopy, Scanning electron microscopy (SEM), DSC, TGA, and Powder x-ray diffraction (PXRD) were applied to IPN samples. In vitro and swelling studies were also employed to observe the response of these polymeric networks against 1.2 and 7.4 pH. TGA and DSC of an optimized loaded formulation possess better thermal stability as compared to individual drug. PXRD depicted minor crystallinity and a significant amorphous nature. SEM images show that polymeric networks possess an uneven and porous surface. Significant swelling and enhanced in-vitro outcomes at a high pH of 7.4 confirmed the IPN pH responsive properties. Toxicological studies performed on rabbits revealed no harm in the results. Thus, IPN based on HPMC/Primojel was successfully synthesized and can be used for LTZ’s controlled release.

The tribological properties of the sponge gourd outer skin fiber (SGOSF)-reinforced epoxy composites filled with tamarind seed powder were investigated using a pin-on-disc dry sliding wear testing machine. The fiber and filler contents were kept constant (30 and 7.5 wt%). The fibers were treated with sodium hydroxide (NaOH), which increases the bonding strength that has been identified by scanning electron microscope (SEM). A filler content of 7.5 wt% has better hardness due to the embedment of filler with treated fiber and epoxy. Therefore, the SGOSFs/epoxy with 7.5 wt% tamarind filler was chosen for the study of tribological characterization. The lowest specific wear rate of 2.565 × 10 −4  mm 3 ·N m −1 was obtained using the design of expert optimization technique for the control factors such as a load of 44.99 N, a sliding distance of 1,701.39 m, and a sliding velocity of 3.36 m·s −1 using a ramp plot at the desirable level of 1. For the gripping material application, the highest coefficient of friction value of 0.51 was obtained by maintaining the specified input parameters, such as a load of 42.15 N, a sliding distance of 1,874.86 m, and a sliding velocity of 4.99 m·s −1 using a ramp plot at the desirable level of 0.927. SEM images were used to investigate the failure mechanism of the worn surfaces, which substantiates the failure of the pure matrix layer on the surface even at low load, followed by the formation of a rarely breakable adhesive layer.

Because of its low thermal stability and brittleness, both the drawbacks of poly( l -lactide) (PLLA) were solved by forming stereocomplex (ST) and its copolymer with poly(butylene adipate- co -terephthalate) (PLLA–PBAT). In this study, we synthesized PLLA and PLLA–PBAT copolymer by ring-opening polymerization. Both polymers were blended with poly( d -lactide) to form ST crystals. Multi-walled carbon nanotubes (MWCNTs) were added into the polymer matrix at 5 phr by the solvent casting method. The surface resistance of the composite was ≅10 6 Ω, which is appropriate for electrostatic dissipative purposes. The copolymer and its ST crystallites were confirmed by the peaks in infrared spectra at 922 and 908 cm −1 , respectively. The PLLA–PBAT copolymer had 60% lower tensile strength than PLLA and its stereocomplex, but 10% higher elongation at break. The elongation at break of the PLLA–PBAT copolymer/MWCNT composite decreased by 17% while its thermal stability slightly increased when compared to the unfilled copolymer. The melting temperature for both ST PLLA–PBAT copolymers, with and without MWCNTs, was around 225°C, which is 50°C higher than that of the homocrystals. Moreover, the glass transition temperature and crystallinity of the ST PLLA–PBAT copolymer also increased by adding MWCNTs.

Surgery, chemotherapy, and radiation therapy are all forms of cancer treatment, as well as more recent methods including interventional radiology and immunotherapy. In this study, we synthesize a novel chitosan (CH) nanocomplex (NC)-based polysaccharide Krestin (PSK) for drug delivery. This technique was used to develop PSK@CH@NC. According to the study, PSK@CH@NC had a particle size of around 500 nm, slight polydispersity as observed under a scanning electron microscope, and a strong positive surface charge of 18 mV. Investigation into the in vitro growth inhibition of the MCF-7 cell line after treatment with CH, PSK, and PSK@CH@NC was followed by morphological changes. Compared to other treatment groups, PSK@CH@NC therapy dramatically reduced the fraction of apoptotic cells, cancer cell survival, and proliferation. Fluorescence analysis was used to examine how PSK@CH@NC affected the distribution of cell cycle phases. This study also shows that a promising foundation for creating cancer nanomedicine can be established by employing new polysaccharides.

In this work, the attenuation properties of silicon rubber (SR) composites reinforced by both micro- and nano-sized Tungsten trioxide (WO 3 ) particles are studied. Different SR composites with different combinations of micro-WO 3 and nano-WO 3 have been prepared. The main composite, SR-(WO 3 ) 60m (40% SR containing 60% micro-WO 3 ), and other compositions were prepared by replacing percentages of microparticles with nanoparticles of WO 3 . The linear attenuation coefficient for these composites was measured in the range of 0.06–1.333 MeV. The existence of micro and nanoparticles together may result in enhanced interactions with incoming photons, leading to greater shielding. In other words, micro-WO 3 and nano-WO 3 have various sizes and surface areas. At 0.06 MeV, we notice a distinguished decrease in the half value layer (HVL) from SR-W60m to SR-W60n. The sequence of reducing HVL values (SR-(WO 3 ) 60m > SR-(WO 3 ) 60n > SR-(WO 3 ) 40m20n > SR-(WO 3 ) 20m40n > SR-(WO 3 ) 30m30n ) suggest that the inclusion of both micro- and nano-WO 3 contributes to more efficient radiation shielding compared to the reference material. The radiation shielding efficiency (RSE) for SR-(WO 3 ) 30m30n at 0.662 MeV is 38.40%. This means that if a beam of photons with energy of 0.662 MeV interacts with SR-W40m20n sample, only 38.12% of the photons are successfully absorbed or stopped, whereas the remaining 61.88% can pass through this sample. At 1.333 MeV, the lowest RSE is observed, which means that the prepared composites have weak attenuation ability at higher energy levels.

In this work, the damage accumulation and failure mechanism of glass fiber-reinforced epoxy composite laminates under repeated low velocity impacts were studied considering the influence of stacking sequence. The typical sandwich-like [0° 2 /90° 2 ] s , angle-ply [±45°] 2s and quasi-isotropic [0°/−45°/45°/90°] s laminates were tested at 20 J impact energy. The impact responses including contact force–time/central displacement and energy–time curves were recorded. The tendencies of the peak contact force, maximum displacement, bending stiffness, and energy dissipation with the increase in impact number were analyzed. Damage induced in the laminates was further evaluated. The results show that the impact resistance of the sandwich-like laminate is the weakest with the lowest peak load and the highest energy dissipation. The impact resistance of the quasi-isotropic laminate is better relative to the angle-ply laminate before the occurrence of fiber breakage, whereas the damage tolerance of the angle-ply laminate is higher with relatively slower damage accumulation at subsequent impacts.

The present work aims to study the effect of the CuSO 4 additive on the physical and radiation-shielding properties of polyepoxide resins. As a result, a series of four samples with the chemical composition x CuSO 4 + (100 − x ) (epoxy resin and hardener) was synthesized. The fabrication of samples was performed under atmospheric pressure and at room temperature. The density of the fabricated CuSO 4 -doped polyepoxides resin was measured experimentally using an MH-300A densimeter with an accuracy of 0.001 mg·cm −3 . A narrow beam transmission method with an NaI (Tl) detector was used to evaluate and describe the effect of CuSO 4 on the linear attenuation coefficient of the fabricated composites in the γ-ray energy interval, which ranged between 33 and 1,332 keV. The estimated results showed a high enhancement in the µ values that increased from 0.259 to 1.749 cm −1 , raising the CuSO 4 concentration from 0 to 40 wt% at a γ-photon energy of 33 keV. The enhancement in the µ values decreased with an increase in the γ-photon energy to 1,332 keV, whereas the µ values increased from 0.077 to 0.102 cm −1 with an increase in the CuSO 4 concentration between 0 and 40 wt%, respectively. This showed that increased µ values positively affected the half-value thickness ( Δ 0.5 , cm), mean free path ( λ , cm), lead equivalent thickness ( Δ eq , cm), and the transmission factor (%); all of the mentioned parameters suffer a considerable decrease with increasing CuSO 4 concentration between 0 and 40 wt%.

To obtain better airflow field characteristics of melt-blowing and acquire slender melt-blowing fiber, a new die with multi-channel of melt-blowing airflow was designed. The airflow field under the spinneret hole of the melt-blowing die was simulated and analyzed using computational fluid dynamics method, and distribution rules of the ordinary die and the new die on the airflow field along the spinning centerline were compared and discussed. The melt-blowing fiber diameter distribution for the ordinary die and the new die was numerically calculated using a stretching model of the melt-blowing fiber. In contrast with an ordinary die, the new melt-blowing die enhances the average speed in main stretching zone by 89.8% and increases the peak speed by 50.4%. The higher airflow temperature of new die improves the softening degree and melting fluidity of the polymer. Meanwhile, the smaller turbulence intensity and the reverse speed of the new die make airflow more stable and reduce disturbance and adhesion of the fiber, and a larger pressure difference and a peak pressure can accelerate the refinement and attenuation of the fiber. The new melt-blowing die with airflow multi-channel is conducive to extension, which is a better choice in the manufacturing process of nonwoven melt-blowing fibers.

Cellulose acetate oleate (CAO)-reinforced poly(butylene adipate- co -terephthalate) (PBAT) composites were prepared by the solvent casting method. The influence of the addition of CAO on the mechanical property, thermal property, disintegration property, compatibility, and hydrophobicity of PBAT/CAO composites was investigated. Compared with PBAT, the tensile strength and Young’s modulus of PBAT/CAO with 4 wt% CAO were increased by 9.5% and 25.7%, and the disintegration rate was also increased by 2.8 times. The results of morphological property, contact angle, and water vapor transmission indicated that the PBAT/CAO composites had good interfacial interaction and compatibility, and the hydrophobicity was improved. PBAT/CAO was applied to strawberry preservation, and it showed excellent freshness retention performance. Moreover, a possible degradation pathway for PBAT/CAO composite was proposed. This work provided a way for the preparation and performance improvement of biodegradable materials, which is expected to be applied in the packaging field.

The radiation shielding characteristics of the polyester resin composites reinforced with cerium( iv ) oxide (CeO 2 ) have been studied. The prepared composites were pure polyester–resin (Poly/CeO 2 -0), 90% per weight polyester resin and 10% CeO 2 (Poly/CeO 2 -10), (Poly/CeO 2 -30), (Poly/CeO 2 -50), and (Poly/CeO 2 -60). The linear attenuation coefficient (LAC) values for the free polyester and polyester samples with CeO 2 were experimentally measured compared with the XCOM data. The experimental LAC value was found to be 0.2377 cm −1 at 0.0595 MeV, which is in good agreement with the calculated value of 0.2454 cm −1 . Also, for the same sample, the experimental LAC was found to be 0.1034 cm −1 at 0.662 MeV, showing a good agreement with the calculated value of 0.1057 cm −1 . The LAC values for the free polyester, Pol/CeO 2 -30, and Pol/CeO 2 -60 are 1.43, 31.82, and 107.77 cm −1 at 0.015 MeV, respectively. The big difference in the LAC values between the composite with 0 and 60% CeO 2 is evident. The radiation shielding efficiency (RSE) of the polyester with different amounts of CeO 2 was experimentally measured at four energy values. Also, we extended the calculation of RSE at other energy values in the range of 0.015–15 MeV). The exposure buildup factor (EBF) values for the free CeO 2 sample and the samples with CeO 2 are calculated. The EBF is small at low energies, then increases, and attains a maximum value at moderate energy; the EBF shows a decreasing trend with an increase in the energy.

N , N -Di-2-propyn-1-yl-2-furanmethanamine (DPFA) was synthesized from 2-furanemethylamine and 3-chloropropyne. Then, furan-containing polytriazoles were made from DPFA and diazide compounds. The Diels-Alder (DA) reaction between 4,4′-bismaleimidodiphenylmethane and furan-containing polytriazoles was used to prepare recyclable polytriazole resins. The effects of the main chain structures on the reversible processes and mechanical properties of the resins were investigated. The results show that the flexibility of the chain structures could be regulated by introducing different contents of azide-terminated polyethylene glycol (PEG) in the polymerization process. The PEG segments could not only promote the degree of the DA reaction but also play a role in reinforcing and/or toughening the recyclable polytriazole resins. RFPTA-5 resin film displays a tensile strength of 107.2 MPa and RFPTA-20 resin film shows an elongation at break of 224.8%. Moreover, the resin films demonstrate high recyclability. Graphical abstract

Chitosan (CS) is widely used in the treatment of wastewater containing metal ions. However, the poor stability in acidic aqueous solutions severely limits its application in many practical scenarios. In this work, a CS-based composite nanofiber membrane was prepared by electrospinning using urushiol, a natural biomaterial, as the cross-linking agent. The application of the CS-urushiol (CS-U) membrane in the adsorption and recovery of Cr( vi ) in wastewater was systematically studied. The CS-U membrane showed great resistance to strongly acidic and oxidative environments, and the adsorption process combined two mechanisms of electrostatic attraction and redox reaction. Due to the nanoscale fibers, porous structure, and strong acid resistance, the CS-U membrane adsorbed Cr( vi ) rapidly and efficiently in both batch and continuous modes. Moreover, the adsorption capacity and selectivity of the CS-U membrane for Cr( vi ) could be maximized simultaneously by adjusting the solution pH, promoting the recovery of high-purity Cr 2 O 3 .

Electromagnetic shielding (EMS) fabric is an effective way to prevent electromagnetic (EM) radiation. However, the research about mechanism analysis of the fabrics’ structure, EM wave (EMW) incident direction, and EMW frequency on the EMS properties of knitted fabrics is discordant at present. Meanwhile, researchers are focused on improving the EMS efficiency of the fabric but rarely discussed the thermal-wet comfort of the fabric. Therefore, in this study a series of weft-knitted fabrics within stainless steel/cotton (30/70) blended yarns were knitted, and the effects of EMW incident direction, stitches, loop lengths, and frequency on EMS effectiveness (EMSE) were analyzed. Meanwhile, the EMS property, warmth retention property, air permeability, moisture permeability, and bursting strength were selected as the evaluation index to evaluate the comprehensive properties of the fabrics by fuzzy mathematics. The results showed that all factors had different degrees of influence on EMSE, and the weft inlay stitch had both the functionality and thermal-wet comfort, which was excellent EMSE in knitted fabric. These results are expected to provide a reference to the design of EMS weft-knitted fabrics.

Emulsification is the effect of a liquid being uniformly dispersed as tiny droplets in another liquid that is immiscible. Traditional emulsification requires the addition of suitable surfactant to stabilize the emulsion. When the surfactant molecules are replaced by solid particles, the emulsion is known as Pickering emulsions (PEs). PEs with dispersed phase volume fraction above 74% are also named high internal phase Pickering emulsions (HIPPEs). The use of solid particles of natural origin allows PEs to be highly physically stable, environmentally compatible, and biodegradable compared to traditional emulsions. Among them, protein-based solid particles are well suited to stabilize PEs for their great emulsification properties and nutritional value. In this article, we reviewed the preparation of different forms of proteins and their emulsion stabilization properties and summarized the applications of protein-based PEs in various fields, including food, biomedicine, porous materials, biodegradable packaging films, sewage treatment, 3D printing, etc. Graphical abstract Particle morphology and applications of protein-based PEs.

The threats of nonrenewable energy consumption and environmental disruption caused by the extensive use of metals and polymers derived from petroleum have prompted the development of eco-friendly, high-performance, and long-lasting structural materials. After various treatments, cellulose materials exhibit exceptional properties such as high strength, fire resistance, hydrophobic properties, and thermal stability. Cellulose-based structural materials have excellent mechanical strength and the distinct advantages of being lightweight, inexpensive, and energy efficient. This review summarizes the recent progress in the preparation methods and properties of high-performance cellulose structural materials such as high-strength cellulose structural materials, thermal insulation cellulose structural materials, flame-retardant cellulose structural materials, hydrophobic cellulose structural materials, cellulose structural material with electrical properties, and other cellulose structural materials. The future of high-performance cellulosic structural materials and the prospective of their development are concluded.

The flammability properties of polymers and polymer composites are crucial in ensuring their safe use in various applications. The development of flame-retardant technologies continues to be an active area of research to improve the fire safety of these materials. Recently, ionic liquids have been studied in the flammability properties of polymers and polymer composites. In this concise review, different types of polymers and polymer composites that are combined with ionic liquids are discovered. In addition, the preparation of polymers and polymer composites combined with ionic liquids through distinct methods is described. The additive effect of ionic liquids on the flammability properties of polymers and polymer composites is also concisely reviewed. The data demonstrated in this review contribute an extra visible knowledge of the preparation of polymers and polymer composites combined with ionic liquids and their flammability properties. In summary, certain types of ionic liquids can decrease the flammability properties of polymers and increase the flame retardancy of polymer composites.

Polymer-based nanocarriers are created from natural or synthetic polymers that are modified to form submicroscopic particles. The polymer matrix can be customized to provide specific properties, such as surface chemistry and flexibility. This allows the particles to be designed and used in different fields. They are promising nanomaterials that are used as therapeutic and diagnostic agents, and they have potential biomedical and environmental applications. These nanocarriers are polymers that can be engineered with other types of nanomaterials with different sizes, shapes, and compositions. They can deliver drugs or their cargo to a specific site with precisely controlled release. They have many advantages compared to traditional drug delivery carriers, including improved biocompatibility, reduced toxicity, and increased efficacy. In biomedical applications, polymer nanocarriers have been used as drug delivery carriers, cancer therapy, and gene therapy. In environmental applications, polymer nanocarriers are able to remove heavy metals and other contaminants from air and water bodies. In this review, a summary of recent fabrication, design, synthesis, characterisation, and various applications in the biomedical and environmental fields has been provided. The review also highlights the current challenges and prospects of evolving polymer nanocarriers.

Bead foams have been widely used for more than 70 years, with expandable polystyrene and expanded polypropylene (EPP) being the main materials. There are different processes for producing bead foams, depending heavily on the material used (e.g., their thermal behavior). EPP is usually produced by a discontinuous stirring autoclave process, which is the main subject of this study. In this process, thermal treatment during the saturation phase leads to the formation of a second melt peak, which is considered an important prerequisite for the subsequent welding process, in which the individual foamed beads are welded into complex shaped parts by applying saturated steam to the beads in a cavity (so-called steam chest molding). To date, EPP is one of the main bead foams used industrially, but other materials such as polylactide and thermoplastic polyurethane can also be processed using the same technique. This review focuses on the important thermal and physical mechanisms during saturation and expansion and the parameters (material and process) that affect them. The process itself provides multiple possibilities to influence thermal behavior (i.e., crystallization) and expansion. Typical properties of resulting bead foams, which are found in many applications, are also considered.

Hybrid nanogels that are both thermosensitive and superparamagnetic, and have good biocompatibility are expected to have applications in the biomedical field. In this article, a linearly thermosensitive magnetic microgel was prepared by a radical copolymerization reaction in aqueous dispersion. In this reaction, poly(ethylene glycol) diacrylate was used as a crosslinker, polyvinylpyrrolidone was used as a stabilizer, and 2-methoxyethyl acrylate, poly(ethylene glycol)methyl ether acrylate, and 2-(methacryloyloxy)ethyl acetoacetate were used as copolymer monomers. The thermosensitive magnetic microgel displays a linear volume phase transition in water upon heating over a wide range of temperatures. Transmission electron microscopy, scanning electron microscopy, and dynamic light scattering were used to characterize the morphology and dimensions of the thermosensitive magnetic microgel. This material is expected to be used in magnetically targeted drug delivery systems that require linear drug release. Graphical abstract

In this work, proton-conducting membranes have been prepared by entrapping human nail keratin in bacterial cellulose at different mass ratios. Bacterial cellulose was obtained by fermenting coconut water with the Acetobacter xylinum bacterium, and keratin was obtained from human nails. The membrane is produced by the blending and heating process at a temperature of 40°C. FTIR spectroscopy showed the interaction between bacterial cellulose and human nail keratin at a peak area of 3,000–2,000 cm −1 . The X-ray diffraction analysis has confirmed the effect of keratin mass on the diffractogram pattern of the membranes. The maximum proton conductivity has been measured as 4.572 × 10 −5  S·cm −1 at 25°C and produces a degree of swelling of 32.50% for a mass ratio of bacterial cellulose/human nail keratin 4:1.

It is vital to conduct research on the behaviour of natural fibre composites under cyclic loading in order to have confidence in the mechanical durability. During this study, the fabrication of composite laminates will be carried out by the hybridization effect of natural and synthetic fibres. Quantifying the impact that the SiC filler (10, 20, and 30 g) has when combined with the fibre reinforcement and epoxy matrix (275 g) under cyclic loading circumstances and determining the significant sequence of hybrid composites are the goals of this research. The results of the tensile mode were used to determine the input parameters, and based on the tensile strength of the hybrid composite, 70% of the tensile strength was fixed at 3 Hz frequency as the input for fatigue analysis. The life span was then determined for the hybrid composite. The results of this fatigue test showed that increasing the amount of SiC nanofillers produced a very high potential output for the fatigue test. As a result of increasing the amount of silicon carbide fillers from 10 to 30 g, sample S3 was able to significantly tolerate 65% more life. Failure mode can be identified from scanning electron microscope analysis revealing the major porosity, matrix crack, and laminate bonding strength that causes the failure during fatigue analysis.

This work investigated the thermal, morphological, and tensile properties of poly( l -lactide)- b -poly(ethylene glycol)- b -poly( l -lactide) (PLLA-PEG-PLLA)/thermoplastic starch (TPS) blends with 3 wt% citric acid (CA) treatment of TPS. The blends with PLLA-PEG-PLLA/CA-TPS ratios of 100/0, 90/10, 80/20, and 60/40 (w/w) were investigated and compared with PLLA-PEG-PLLA/CA-free TPS blends. Crystallizability of the blends decreased and thermal stability increased as the TPS content increased. The thermal stability of the blends was found to improve after CA treatment of TPS. The PLLA-PEG-PLLA/CA-TPS blends showed better phase compatibility than those of the PLLA-PEG-PLLA/CA-free TPS blends. The tensile properties of the blends were improved by CA treatment of TPS. In conclusion, improvement in thermal stability, phase compatibility, and tensile properties of the PLLA-PEG-PLLA/TPS blends was obtained by CA treatment of TPS. The resulting PLLA-PEG-PLLA/CA-TPS blends could potentially be used to prepare biodegradable and flexible bioplastics.

Cancers are complicated sicknesses that happen because of many different things going wrong in cells, and as they get worse, the cells undergo many changes one after another. Nanomedicine is a new way to treat diseases like cancer. Tiny particles called nanoparticles have special properties that can help to treat diseases better than regular treatments. These particles are very small but have a lot of surface area, can carry different drugs, and can be designed to target specific areas. They can move around the body, go into cells, and release drugs slowly. Because of these benefits, nanoparticles could be better for cancer treatment. In this continuous research, we present a simple technique for the quick and single-step synthesis of ZnFe 2 O 4 /cellulose nanocomposites, employing the polymer cellulose. This method is not only cost-effective but also environment friendly. Scanning electron microscopy, powder X-ray diffraction, Fourier transform infrared spectroscopy, and the ultraviolet-visible (UV) spectrum were all used to examine the morphological, structural, and electrical properties of ZnFe 2 O 4 /cellulose nanocomposites. The nanocomposite derived from UV-DRS exhibits an optical energy bandgap of 1.8 eV. The mechanical strength of the composites gradually increases as ZnFe 2 O 4 is added to the cellulose polymer matrix. These findings propose a straightforward and innovative approach to produce ZnFe 2 O 4 /cellulose nanocomposites that can serve as functional biomaterials. In addition, the ZnFe 2 O 4 /cellulose nanocomposite exhibits decreased antioxidant activity compared to ascorbic acid. ZnFe 2 O 4 /cellulose nanocomposite was found to have an IC 50 of 49.64 g·mL −1 . With an IC 50 value of 55.91 g·mL −1 , the synthesized ZnFe 2 O 4 /cellulose nanocomposites demonstrate significant cytotoxicity in a dose-dependent manner against the lung cancer cell lines A549. In conclusion, nanocomposites are potential materials for usage in biomedical applications due to their affordable production and mild magnetic sensitivity.