Volume 22, Issue 1

The effects of isothermal crystallization temperature/time on mechanical properties of bio-based polyester poly(ethylene 2,5-furandicarboxylate) (PEF) were investigated. The intrinsic viscosity, crystallization properties, thermal properties, and microstructure of PEF were characterized using ubbelohde viscometer, X-ray diffraction, polarizing optical microscope, differential scanning calorimetry, and scanning electron microscopy. The PEF sample isothermal crystallized at various temperatures for various times was denoted as PEF- T - t . The results showed that the isothermal crystallization temperature affected the mechanical properties of PEF- T -30 by simultaneously affecting its crystallization properties and intrinsic viscosity. The isothermal crystallization time only affected the crystallization properties of PEF-110- t . The crystallinity of PEF-110-40 was 17.1%. With small crystal size, poor regularity, and α′-crystal, PEF-110-40 can absorb the energy generated in the tensile process to the maximum extent. Therefore, the best mechanical properties can be obtained for PEF-110-40 with the tensile strength of 43.55 MPa, the tensile modulus of 1,296 MPa, and the elongation at a break of 13.36%. Graphical abstract The crystallization temperature/time and mechanical properties of PEF are investigated. The mechanical properties of PEF are effectively improved only by controlling the crystallization parameters without adding a modifier.

The development of the composite materials in the past decades has made the composite materials more and more widely used in various engineering fields. The mechanical properties of the composite materials are gradually improved, especially the impact resistance. In this article, the damage of carbon fiber foam sandwich structure (material grade: W-3021FF/H60) under different sandwich thicknesses and impact energies was studied. Ultrasonic C-scan was used to measure the depth and area of impact damage area. Finally, the impact energy and foam core thickness on impact damage was analyzed by test results. The results show that the impact damage depth and area of foam sandwich structure were positively related to the impact energy, and with the increase in the impact energy, the growth rate of damage depth and damage area changes; the greater the thickness of the foam core was, the stronger the span-direction guiding energy for impact energy, the larger the damage area and the smaller the damage depth. Under the same energy, the more the layers of carbon fiber cloth with the foam sandwich structure, the larger the impact damage depth and the smaller the impact damage area. The proportion of ±45° ply in the foam sandwich structure can improve its impact resistance.

A series of hyper-crosslinked polymers (HCPs) with connected hierarchical porous structures were synthesized from phenyl-based precursors of benzene (BEN), benzyl alcohol, aniline, biphenyl, and 1,3,5-triphenylbenzene (TPB) via the knitting method. The porous structures of the HCPs were greatly influenced by substituent groups and BEN ring number in the precursors. HCPs prepared from TPB had the largest surface area and pore volume with multiscale porosity. The porous structure of the HCPs could also be adjusted by the crosslinker amount. Insufficient crosslinking led to incomplete pore architecture, while excessive crosslinking resulted in a considerable decrease in the pore volume. With these HCPs as adsorbents, the BEN yield in the cigarette smoke could be largely reduced due to the connected multiscale porosity and π–π aromatic stacking interaction that facilitated the smoke aerosol passing and the small aromatic molecules absorbing, showing great potential of these HCPs as adsorbents for effective removal of BEN from cigarette smoke.

Large amounts of textile waste are generated every year and disposed of through landfill or incineration, leading to numerous environmental and social issues. In this study, waste hybrid polyethylene terephthalate (PET)/cotton fibers were used directly to reinforce high density polyethylene (HDPE) to prepare composites. In order to give full play to the fiber’s reinforcing characteristics, the PET/cotton fibers were further modified with the modifier using a novel synthesized tetraethyl orthosilicate/3-aminopropyl triethoxysilane (KH550)/polyethylene (PE)- g -MAH (MPE) hybrid (TMPE). Fourier transform infrared and scanning electron microscopy (SEM) confirmed that the TMPE was successfully coated on the surface of fibers. Furthermore, compared with the original and the MPE-modified fibers, the thermal stability of TMPE-modified fibers was significantly increased. SEM and mechanical test indicated that the compatibility of the modified fibers with HDPE had been significantly improved, which led to the improvement of mechanical properties. Compared with the original and MPE-modified fibers-reinforced HDPE composites, the bending strength, bending modulus, and impact strength of TMPE-modified fiber-reinforced HDPE composites were improved obviously by 31.7%, 25.7%, and 89.1%, respectively.

In this article, water-based polyurethane (PU) with different concentrations and partial alcoholysis polyvinyl alcohol (PVA) were used to coat polyester (PET) harness cord in turn. The surface and mechanical properties of harness cord before and after coating were evaluated by performing the tests of dynamic contact angle, morphology observation, bending properties, tensile properties, and wearability. It was found that the surface properties of 1.5% PU-coated harness cord tended to be stable, and the mechanical properties of PU(1.5%)/PVA-coated harness cord were optimal. Compared with PVA-coated harness cord, the wearability of PU(1.5%)/PVA-coated harness cord showed a great increment up to 135.7%. This was because the PU coating effectively improved the interfacial properties between the PVA coating and the hydrophobic PET fibers and enhanced the adhesion of the PVA coating to the PET fibers.

Silk fibroin (SF) film is an insulating material, which can be combined with polythiophene derivatives with electrical conductivity to obtain a flexible conductive material. In this work, poly(3,4-ethylenedioxythiophene) (PEDOT) was used to graft a silk protein film. The hydroxyl radical is formed by activation and oxidation of the silk protein film polymerized with the PEDOT radical formed by oxidation of 3,4-ethylenedioxythiophene to obtain a conductive silk film. The SF/PEDOT film, when tested, showed excellent electrical conductivity with resistance up to 63 Ω·cm −2 , good flexibility, mechanical properties, fastness, and biocompatibility. Graphical abstract Preparation of SF/PEDOT film and its property display.

This research focuses on the synthesis and adhesive properties of mucoadhesive mats, prepared with poly(vinylic alcohol) as a base polymer for the oromucosal release of propranolol (PRO) by the electrospinning technique. The nanofibers mats were evaluated by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry; in vitro drug entrapment efficiency, degradation time, and adhesion studies were performed. SEM images of the electrospun mats show the correct formation of fibers with a variable diameter and porosity. Thermal studies indicate excellent thermal stability of the scaffolds, The fibrous mats loaded with 10% of the drug exhibit the best thermal stability with decomposition after 450°C. In vitro studies indicate a drug content of 88% loaded in the mats. In the cytotoxicity test, loaded mat presents cell proliferations of 97% and 88% for drug concentrations of 10% an 15%, respectively. To conclude, the formed electrospun adhesive mats exhibited excellent thermal stability, adhesive properties, and drug entrapment efficiency, promising features for a successful drug topical release system on mucosal tissue in the oral cavity.

Polypropylene (PP) undergoes fast crystallization and resulting in rigorous shrinkage when it is subjected to high temperature likewise of the fused deposition modeling (FDM) process. This research study focuses on the investigation of the processing parameters and factors that decrease the warpage of PP during the FDM process. Aluminium silicate dihydrate (K) microparticles of different ratios were melt blended with PP by a twin-screw extruder, and filaments of about 1.7 mm diameter were extruded in a single screw extruder. Then, the extruded filaments were used to fabricate the dumbbells structure through the FDM process. The effects of optimizing the fused deposition temperature, coating the chamber with thick papers/fabrics, and coating a printer bed with PP material were also investigated in this study. Scanning and transmission electron microscopy, differential scanning calorimetry, melt flow, and mechanical properties testing instruments are used to analyze the microparticles dispersion, crystallization, flow, and mechanical properties of resulting samples. Uniformly dispersed filler and increased printing chamber temperature result in an increase of crystallization temperature and improve the dimensional accuracy of fused deposited specimens. The fused deposited PP-K10 wt% composite showed an improvement of up to 32% in tensile modulus compared to the neat PP.

In this study, kraft lignin and epichlorohydrin (ECH) were used to prepare no-formaldehyde wood adhesives. The lignin was first treated by ball milling, then reacted with glyoxal to produce glyoxalated lignin under alkaline conditions, and then blended with ECH to prepare lignin-based formaldehyde-free adhesive. The influence of the content of ECH on the physicochemical properties of the adhesives was explored, and the possible synthesis mechanism of the ECH-modified glyoxalated lignin adhesives (glyoxalated kraft lignin-epoxy [GKLE]) was investigated. The results show that ECH was beneficial to improving the plywood shear strength and water resistance; the plywood prepared with GKLE-50 adhesive displays comparable water resistance as phenol–formaldehyde resins and its wet shear strength (type I) was 1.05 MPa, exceeding the Chinese National Standards GB/T 9846-2015. Scanning electron microscopy analysis showed that the increase of ECH content promoted the adhesive to penetrate the wood to form glue nails, improving the wet shear strength of the plywood. Chemical analysis indicated that glyoxalation was used to introduce hydroxyethyl groups into the ortho positions of the aromatic rings of lignin, and then the ring-opening reaction between glyoxalated lignin and ECH occurred forming ether bonds. Overall, lignin has displayed great potential in replacing formaldehyde-based adhesives for industrial applications.

Aralia continentalis Kitagawa and ginseng are both perennial herbs of Araliaceae. The study aimed to investigate the composite packaging films with better fresh-keeping ability. The different mass concentrations of Aralia continentalis Kitagawa root extract (ARE) 0.05%, 0.10%, and 0.15% (v/w) were compounded with chitosan (CH) to make composite packaging films. Food-based composite film, its thickness, density, water contact angle (WCA), oxygen barrier properties (OP), solubility, swelling, transparency, water vapor permeability (WVP), and other physical properties, as well as tensile strength (TS), elongation at break (EAB), Young’s modulus (YM), and the mechanical properties were measured, and the oxidation resistance, thermal properties, and biodegradability were also evaluated, and the structure was analyzed by infrared spectroscopy. The results showed that when the ARE content in the film was increased from 0.05 to 0.15 mg·mL −1 , high antioxidant capacity of the CH/ARE film was exhibited (the DPPH and ABTS + free radical scavenging rate was increased), and the thickness, density, swelling degree, solubility, TS, EAB, and YM of the CH/ARE composite film increased, while WCA, OP, WVP, transparency, and biodegradability were slightly reduced. We had noticed that with the increase in the ARE content, the surface microstructure in CH/ARE film changed significantly, indicating the good compatibility between CH and ARE. In summary, as a natural active substance, ARE can be combined with CH to form films, and the packaging film made can effectively improve the performance of the composite film.

Molecular dynamics simulations on the nonisothermal crystallization of a single polyethylene chain and short polyethylene chains based on the all-atom model and optimized potentials for liquid simulations-all atom (OPLS-AA) force field are conducted in this article. Four all-atom single chain models with different chain lengths (C1000, C2000, C3000, and C4000) and four all-atom short chain models with the same chain length and different number of chains (2C500, 4C500, 6C500, and 8C500) are constructed. The collapse process at a high temperature of 600 K and the nonisothermal crystallization process with different cooling rates at the temperature range of 600–300 K are simulated. Roles of chain length, number of chains, cooling rate on the potential energy, van der Waals ( V dw ) energy, radius of gyration, root mean square deviation, and crystallinity are explored. By comparing with the existing results obtained by the united atom model, the validity and accuracy of this study are proved. Results show that in the collapse process, the chain length is the major factor, whereas the cooling rate has the greatest influence during the nonisothermal crystallization process. As the cooling rate decreases, a “platform” appeared in the V dw energy curve, which has a profound impact on the crystallization.

The polycaprolactone diol (PCL diol) was prepared by ring-opening polymerization method, with hydroquinone bis(2-hydroxyethyl) ether as the reactive initiator and ε-caprolactone as the monomer. The polyurethane acrylate (PUA) was prepared with the self-made PCL diol. Then, PUA was used to prepare the ultraviolet curable coatings. The structure and molecular weight of PCL diol was characterized by Fourier transform infrared spectroscopy, gel-permeation chromatography, and hydroxyl value titration. The performance of the cured coating film was characterized by thermogravimetric analysis and scanning electron microscope. The flexibility and hardness of the cured coating film were tested. The results showed that the narrow molecular weight PCL diol was successfully synthesized. The UV curing coating film had the optimal performance with a hardness of 3H, flexibility of 1.5 mm, abrasion resistance of 0.028 g −1 , and adhesion of grade 1, all coating films showed good thermal properties.

Ionic polymer-based conductive composite is a new type of ionic electroactive polymer smart material, which is composed of two electrodes, the ion-exchange polymer matrix film and the polymer surface and is a three-layer sandwich structure. The conductive composite material has the advantages of flexibility, portability, and biocompatibility, which has attracted a large number of researchers to study it in the fields of biomimetic flexible actuators and biomedical materials, but the conventional matrix film has the disadvantage of high preparation cost. In this study, using sulfonated waterborne polyurethane membrane as matrix membrane and aniline as monomer, polyaniline (PANI) was synthesized by in situ oxidation polymerization reaction, and the conductive composites with PANI as electrode were prepared. After applying alternating current electric field, a new brake with PANI as electrode is obtained. A low-frequency signal generator was used to study the electromechanical properties of the prepared materials. The results show that the waterborne polyurethane/PANI composite film produces a continuous and stable driving performance at 0.2 Hz and 20 V, and the maximum output displacement of the terminal is 40 mm. When the driving voltage and frequency are changed, the displacement output also changes, showing a good controllable performance. Its structure and morphology were characterized.

The present manuscript describes the synthesis of urethane (ROGAU) coating material from Rapeseed oil (RO), Gallic acid (GA) and Toluylene-2,4-diisocyanate [TDI], for the first time. The reaction was accomplished in the following steps: (i) amidation of RO, producing diol fatty amide, HERA, followed by (ii) gallation reaction of HERA with GA, resulting in RO-based gallate amide (ROGA). The structural elucidation by FTIR and NMR confirmed the insertion of amide and ester moieties in the ROGA backbone. To add applicational value to ROGA, it was then derivatized by urethanation reaction with TDI to develop ambient temperature-cured ROGAU, as a corrosion protective coating material. ROGAU coatings were scratch resistant, well-adherent, and flexible to a considerable extent and showed good corrosion resistance performance toward saline medium (3.5 wt% NaCl). ROGAU coatings can be safely used up to 200°C.

The synthesis of tetrazole-containing derivatives of chitosan, starch, and arabinogalactan was carried out by a sequence of reactions including cyanoethylation of polysaccharides and subsequent azidation of cyanoethyl derivatives. The reaction of cyanoethylation of polysaccharides with acrylonitrile proceeds in the temperature range 40–60°C in the presence of NaOH. The transformation of nitrile groups into tetrazole rings (azidation) of cyanoethylated polysaccharide derivatives was carried out with a mixture of sodium azide with ammonium chloride in DMF at 105°C. The reaction with the participation of derivatives of starch and arabinogalactan is characterized by the degree of conversion of nitrile groups into tetrazole rings, which is close to the maximum. The introduction of unsubstituted tetrazole rings into the structure of polysaccharides of acidic N–H substantially changes some of their properties. Like other carbo- and hetero-chain polymers containing N–H unsubstituted tetrazole rings in the structure, tetrazolated polysaccharides exhibit the properties of acidic polyelectrolytes. Tetrazole-containing derivatives of chitosan exhibit the properties of polyampholytes. The presence of tetrazole rings in the structure of modified polysaccharides allows the reaction with epoxy compounds to yield network polymers capable of limited swelling in aqueous media with the formation of polyelectrolyte hydrogels.

Designing versatile rubber as a multifunctional elastomer is of great importance, incorporating it with biomass-derived nanoblocks will mitigate environmental challenges. Here biosynthesized natural rubber (NR) composites with CoFe 2 O 4 -immobilized biomass carbon (BC) derived from macadamia nutshells were fabricated by facile mechanical mixing. Morphological analysis indicates that CoFe 2 O 4 nanoparticles are uniformly anchored on the surface of BC, forming intact electromagnetic loss networks in NR matrix. As a consequence, the as-fabricated NR/CoFe 2 O 4 @BC composites demonstrate enhanced mechanical, thermal, and electromagnetic performance. Particularly, NR/CoFe 2 O 4 @BC composite shows the best microwave attenuation capacity when CoFe 2 O 4 @BC loading is 40 phr, with the minimum reflection loss (RL) of −35.00 dB and effective absorption bandwidth (RL < −10 dB) of 1.60 GHz. All results indicate that this work open new paradigm for multiple applications based on biosynthetic elastomer with the sustainable biomass derived nanoblocks.

In this study, we have produced a lightweight foam composite material by a simple freeze-drying method, which is composed of carboxylated multi-walled carbon nanotubes (MWCNTs), mesoporous carbon hollow microspheres (MCHMs), water-based polyurethane (WPU), and polyvinyl alcohol (PVA). MCHMs were prepared by a novel and facile method. We found that the electromagnetic shielding performance of foam composites can be adjusted by adjusting the density of foam composites, and the electromagnetic shielding performance of composites can be enhanced through the synergistic effect of hollow mesoporous carbon and MWCNTs. The composite material with a density of 232.8042 mg·cm −3 and 40 wt% MWCNT has a δ of 30.2 S·m −1 and SE of 23 dB. After adding 10 wt% MCHMs to the composite material, δ reaches 33.2 S·m −1 , and SE reaches 28 dB. Both absorption losses accounted for 70%. The increase in the content of MWCNT, the increase in density, and the introduction of MCHMs all have a positive effect on the δ and SE of the composite material.

Chitosan (CS) with excellent biomedical properties was mixed with polyvinyl alcohol (PVA) to be used as the spinning solution. The spinning solutions with various concentrations of CS:PVA from 10:90% to 50:50% (v/v) were investigated. Tween 80 (T80) was added in the spinning solutions of CS and PVA. The nanofiber mats with and without T80 addition obtained from the spinning solutions by electrospinning technique were investigated and addressed. The results showed that the viscosity of the CS and PVA spinning solutions increased with increasing the CS concentration, whereas the viscosity decreased after T80 addition. The nanofiber mats with 10–30% CS concentrations were prepared successfully as a smooth surface and high dense nanofiber mat. The average diameter of the nanofiber decreased with increasing the CS concentration. The increase in the CS concentration of the nanofiber mat can increase the mechanical and antibacterial properties, whereas the wettability and drug release property were decreased. Moreover, the nanofiber mats with T80 addition had higher mechanical property and wettability than the nanofiber mats without T80 addition. Finally, the T80 addition can enhance hydrophilicity and promote the drug release property of the nanofiber mat. Graphical abstract

Polyamide 6 (PA6) was modified with ethylene maleic anhydride syndiotactic copolymer resin (ZeMac), and triglycidyl isocyanurate (TGIC) as modifiers to prepare a grafting structure and a long-chain branching structure, respectively. The effects of two modifiers on the rheological behavior, crystallization properties, foaming performance, and mechanical properties of PA6 were systematically studied by rotating rheometry, differential scanning calorimetry and scanning electron microscopy. The results showed that there were differences in crystallization properties between the two modification methods, but they significantly improved the rheological, foaming performance, and mechanical properties of PA6. In particular, PA6 with long-chain branching structure through TGIC modification showed better performance in various physicochemical characterizations. The introduction of ZeMac reduced the average diameter of bubbles in pure PA6 from 146.32 to 88.12 µm, and the density of bubbles increased from 1.69 × 10 5 to 5.35 × 10 5 cells·cm −3 . The introduction of TGIC reduced the average diameter of bubbles in pure PA6 from 146.32 to 64.36 µm, and the density of bubbles increased to 1.31 × 10 6 cells·cm −3 . Moreover, the mechanical properties of both nonfoamed and foamed samples were improved after modification.

The interfacial interaction between the main oxidant filler ammonium perchlorate (AP) and hydroxyl-terminated polybutadiene (HTPB) matrix in AP/HTPB propellants were studied via an all-atom molecular dynamics simulation. The results of the simulation showed the effects of the microscopic cross-linked structure of the matrix, stretching rate during uniaxial stretching, and contact area between the filler and matrix on the mechanical properties, such as the stress and strain of the composite solid propellant. Among the aforementioned factors, the stretching rate considerably affects the mechanical properties of the solid propellant, and the maximum stress of the solid propellant proportionally increases with the stretching rate. When defects were introduced on the surface of the AP filler, the contact area between the filler and matrix affected the strain type of the matrix molecules. Owing to the interaction between the molecules and atoms, the strain behaviour of the matrix molecule changed with the change in its microscopic cross-linked structure during uniaxial stretching. Molecular dynamics simulations were used to explore the characteristics at the AP–HTPB interface in AP/HTPB propellants. The aforementioned simulation results further revealed the interfacial interaction mechanism of the AP–HTPB matrix and provided a theoretical basis for the design of high-performance propellants.

Antimicrobial peptide (AMP) self-assembly is an effective way to synthesis antimicrobial biomaterials. In previous studies, we found PAF26 AMP (Ac-RKKWFW-NH 2 ) and its derivative K 2 –F 2 peptide (Ac- KK RKKWFW FF -NH 2 ) could both self-assemble into hydrogels, but they had distinct microscopic structures. Therefore, in this work five PAF26 peptide derivatives with different numbers of aromatic amino acids are designed to better understand the self-assembly mechanism of aromatic AMP. The transmission electron microscopy, infrared spectroscopy, circular dichroism, and fluorescence spectroscopy characterizations are carried out to study the microscope structure, secondary conformation, and molecular interactions. It is found that the five peptide derivatives have different microscopic structures, and the number of aromatic amino acids will affect the peptide hydrogen bonding and aromatic stacking interactions, causing significant differences in the secondary conformation and microscopic structure. This work will enhance the comprehension of aromatic AMP self-assembly.

Epoxy/polyamic acid (EP/PAA) adhesives with high polyimide precursor-PAA content have been synthesized and then cured. The structure, thermal, and adhesive properties were investigated by Fourier transform infrared spectroscopy, thermogravimetric analysis, and tensile shear test. The effects of PAA content and curing process on the tensile shear strength were also studied. The results showed that the addition of PAA improved the heat resistance and reduced the water absorption. EP/PAA adhesive kept good adhesion. A kind of EP/PAA composite adhesive with excellent comprehensive properties was prepared in this study.

Composite materials are more and more widely used in aircraft structural design, and impact damage is the most serious defect/damage form of aviation composite structures in service. Therefore, it is of great significance to study the impact resistance of composites with different materials and structural forms for aircraft structural design. In this article, the damage of reinforced fiber/resin composite laminates with unidirectional carbon fiber prepreg (UIN23100), carbon fiber woven fabric (W-3021FF), and carbon fiber-aramid fiber blended fabric (W-38211) under the same impact energy were studied. The impact damage area was scanned and analyzed by ultrasonic C-scan, and the impact resistance of the three laminates were obtained. Finally, the compression bearing capacity of carbon fiber laminates after impact was tested, and the compression failure mode of each material has been analyzed. The results show that the impact resistance of carbon fiber unidirectional prepreg was stronger than that of carbon fiber woven fabric; the compression bearing capacity of carbon fiber laminate after impact was higher than that of carbon fiber unidirectional prepreg; the post impact bearing capacity of W-38211 was higher than that of W-3021FF.

Developing novel foams with tailored properties is a challenge. If properly addressed, efficient screening can potentially accelerate material discovery and reduce material waste, improving sustainability and efficiency in the development phase. In this work, we address this problem using a hybrid experimental and theoretical approach. Machine learning (ML) models were trained to predict the density of polylactide (PLA) foams based on their processing parameters. The final ML ensemble model was a linear combination of gradient boosting, random forest, kernel ridge, and support vector regression models. Comparison of the actual and predicted densities of PLA systems resulted in a mean absolute error of 30 kg·m −3 and a coefficient of determination ( R 2 ) of 0.94. The final ensemble model was then used to explore the ranges of predicted density in the space of processing parameters (temperature, pressure, and time) and to suggest some parameter sets that could lead to low-density PLA foams. The new PLA foams were produced and showed experimental densities in the range of 36–48 kg·m −3 , which agreed well with the corresponding predicted values, which ranged between 38 and 54 kg·m −3 . The experimental–theoretical procedure described here could be applied to other materials and pave the way to more sustainable and efficient foam development processes.

The microstructure design of hydrogel materials offers a broad range of practical applications and is extensively used in flexible sensors, polymer microneedles, microfluidic chips, and other biomedical engineering fields. Among the bio-sourced hydrogels, oligomeric hyaluronic acid (HA) possesses wound healing, anti-tumor, and angiogenesis properties. However, micropatterning soft hydrogels, such as HA-relative hydrogels containing 90% water by weight, continue to pose difficulties for both high precision and micro-scale lithography. The purpose of this study was to compare the photolithography and light-cured inkjet printing methods of methacryloyl HA hydrogel (HAMA-gel) to those for synthetic light-curable polymer resins. Photolithography and light-cured inkjet printing methods with designed scale, high resolution, and little processing times were used to effectively prepare micropatterns of HAMA-gel. The well-shaped micropatterns consisted of parallel channels in tens of micrometers and strip/grid lines in the hundreds of micrometers. Human vein endothelial cells cultured on the material’s surface demonstrated that HAMA-gel had good biocompatibility. The width of the flow channel (10 and 20 µm) was regulated on the surface of the microstructure to allow for simultaneous control of cell growth along the flow channel and groove directions.

The systemic toxicity and low efficacy of traditional chemotherapy for hepatocellular carcinoma (HCC) result in poor clinical outcomes. This study was designed to achieve targeted delivery of apoptin plasmid (AP) to liver tumors and killing of cancer cells using multifunctional nanoparticles (MFNPs) having sustained-release properties. The MFNPs featuring a distinct core-shell structure were prepared using poly(lactic-glycolic acid)-ε-polylysine copolymer and loaded with AP by adsorption. Specific targeting of liver tumor cells was achieved by biotinylation of the nanoparticles (NPs), while an improvement in lysosomal escape and nuclear localization enhanced the tumor cell killing capability of AP. Blank MFNPs exhibited good biocompatibility while AP-loaded NPs were found to exert strong inhibitory effects on both tumor cells in vitro and solid tumors in vivo . Taken together, these findings demonstrate a promising route for the development of tumor-targeted NPs which may lead to improved therapeutic strategies for treating HCC.

Octa(dimethylethoxysiloxy) POSS (ODES) was synthesized successfully and used as the novel curing agent to prepare RTV silicone rubber (SROD) with outstanding mechanical properties and thermal stability. Compared with the silicone rubber cross-linked by tetraethoxysilane (SRTE), the novel RTV silicone rubber using octa(dimethylethoxysiloxy) POSS as a cross-linker had better mechanical, thermal, and optical properties. The highest tensile strength of SROD reached 1.26 MPa, which is three times that of SRTE. Besides, the decomposition temperature of 10% weight loss reached 507.7°C, exceeding that of SRTE by nearly 150°C. In addition, it was remarkable that due to the good compatibility of ODES with the silicone rubber matrix, the series of SROD showed good transmittance, greater than 87%. The thermal decomposition process of SROD was investigated by TGA coupled with real-time FTIR, and the results revealed the rigid structure and large steric hindrance of ODES that efficiently blocked the “backbiting” of the polysiloxy chains and delayed the end-induced ring decomposition, and consequently, improved the thermal stability of SROD significantly.

A novel ammonium salt type polymeric antistatic agent (PDSH) was synthesized from methacrylatoethyl trimethyl ammonium chloride, styrene, and 2-hydroxyethyl methacrylate via radical polymerization. Antistatic poly(acrylonitrile- co -butadiene- co -styrene) (ABS)/PDSH composites were prepared by blending PDSH with ABS resin. The results showed that the surface resistivity of ABS/PDSH composites with PDSH addition decreased significantly. The surface resistivity of ABS/PDSH composites containing 20 wt% PDSH was around 10 9 –10 10  Ω, which was about 10 6 times lower than that of neat ABS. At the same time, ABS/PDSH composites had good thermal stability and hydrophilicity. The PDSH was more uniformly dispersed within the ABS resin and had less influence on the mechanical properties of the composites. With the demonstrated properties, the prepared copolymer PDSH can serve as a well-integrated antistatic agent and display potential for the antistatic treatment of ABS.

Boron phenolic resin is widely used in the aerospace field because of its excellent thermal properties. In this article, nitrile rubber powder was added to phenolic resin to modify fiber-reinforced phenolic resin composites. The results showed that the tensile strength continued to decrease; the elongation ratio increased from 20.01% to 32.04%; and flexural strength and flexural modulus reached the highest values of 188 and 9,401 MPa, respectively. Thermal analysis showed that rubber had little effect on the heat resistance at low temperatures, especially below 350°C. Furthermore, the coefficient of thermal expansion of the composites increased from 8.9 × 10 −6 to 1.5 × 10 −5  K −1 , increasing by nearly 70%. The electron microscopy images showed a tortuous fracture path in modified composites, which indicated that rubber powder–modified phenolic composites had a ductile fracture.

In this study, talcum was melt-blended with a flexible poly( l -lactide)- b -polyethylene glycol- b -poly( l -lactide) triblock copolymer (PLLA-PEG-PLLA) with 1, 2, 4, and 8 wt% talcum, for improvement of the crystallization and thermomechanical properties of PLLA-PEG-PLLA compared with PLLA. The crystallizability of PLLA-PEG-PLLA/talcum composites was better than that of PLLA/talcum composites as determined from differential scanning calorimetry. X-ray diffractometry showed that the PLLA-PEG-PLLA/talcum films had a higher degree of crystallinity than the PLLA/talcum films. PEG middle-blocks and talcum showed a synergistic effect for crystallization of PLLA end-blocks. The PLLA-PEG-PLLA/talcum films showed better thermomechanical properties than those of the PLLA/talcum films as determined from dynamic mechanical analysis. This was confirmed from the results of dimensional stability to heat. In summary, the PLLA-PEG-PLLA/talcum composites have potential for use as flexible bioplastics with good dimensional stability to heat.

Although metal–organic frameworks (MOFs) own excellent uranium adsorption capacity but are still difficult to conveniently extract uranium from seawater due to the discrete powder state. In this study, a new MOF-based macroporous membrane has been explored, which can high-efficiently extract uranium through continuously filtering seawater. Through modifying the UiO-66 with poly(amidoxime) (PAO), it can disperse well in a N,N -dimethylformamide solution of graphene oxide and cotton fibers. Then, the as-prepared super-hydrophilic MOF-based macroporous membrane can be fabricated after simple suction filtration. Compared with nonmodified MOFs, this UiO-66@PAO can be dispersed uniformly in the membrane because it can stabilize well in the solution, which have largely enhanced uranium adsorbing capacity owing to the modified PAO. Last but not least, different from powder MOFs, this UiO-66@PAO membrane provides the convenient and continuously uranium adsorbing process. As a consequence, the uranium extraction capacity of this membrane can reach 579 mg·g −1 in 32 ppm U-added simulated seawater for only 24 h. Most importantly, this UiO-66@PAO membrane (100 mg) can remove 80.6% uranyl ions from 5 L seawater after 50 filtering cycles. This study provides a universal method to design and fabricate a new MOF-based adsorbent for high-efficient uranium recovery from seawater.

The application of poly(lactic acid) (PLA) has been limited in flame-retardant field, and flame-retardant modification usually deteriorates its mechanical properties. In this study, a reactive flame-retardant hexa(ethylene oxide)-cyclotriphosphazene (HCCP-EP) was synthesized and used to improve the fire retardancy of PLA. As a result, the limiting oxygen index of PLA increased from 19.5% to 27.3% with an addition of 3 wt% HCCP-EP, and the PLA/HCCP-EP blend reached to underwriters laboratories (UL)-94 V-0 rating. The cone calorimeter test results showed that the peak heat release rate and total heat release of PLA decreased by 12.6% and 18.5%, respectively. Interestingly, the tensile strength of PLA increased slightly after the incorporation of HCCP-EP. The improved mechanical properties are ascribed to the fine dispersion of HCCP-EP and the coupling reaction between the epoxy groups of the HCCP-EP and the terminal groups of PLA during the melt processing.

To improve the fire safety of epoxy resin (EP), two novel phosphorus–nitrogen flame retardants, which named as diphenyl allylphosphoramidate (DPCA) and N-allyl-P, P-diphenylphosphinic amide (DCA), were synthesized by acyl chloride reaction and introduced into EP for fabricating EP composites. The combustion tests showed that incorporation of 5 wt% DPCA or 5 wt% DCA into EP led to the exceptional limited oxygen index (LOI) value (27.1% or 31.6%). Besides, the peak of heat release rate of EP-5 wt% DPCA and EP-5 wt% DCA was reduced by 40.69% and 36.69%, respectively, compared to pure EP. The enhanced fire resistance of EP was ascribed to the trapping effect of fillers in the gas phase and the charring effect in the condensed phase. Furthermore, ultraviolet-visible spectra revealed that both EP-5 wt% DPCA and EP-5 wt% DCA have considerable transparency. This study is expected to broaden the application of EP in the industrial area.

Non-rubber components are critical in the formation of the natural rubber (NR) vulcanization network, which leads to outstanding mechanical properties of NR. This study reports the effect of NR endogenous proteins (C-serum protein/lutoid protein [CSP/LP]) on the formation of vulcanization networks at the molecular level. Results indicate that CSP/LP has a positive effect on vulcanization. Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses demonstrate that the decrease in vulcanization time of CSP/LP is ascribed to coordination interaction between Zn 2+ and amide bond. The interaction increases the availability of ZnO in the matrix, thereby promoting the formation of the vulcanized network. CSP/LP also participates in the construction of the vulcanization network as a new crosslinking point, thus increasing crosslinking density and improving the mechanical properties of the NR. This study provides new research ideas for studying the relationship among component–structure–property of NR materials and developing high-strength and high-toughness elastomer materials.

Polymer nanohybrids have displayed great potential in remobilizing oil droplets through porous media. This research aims at providing some insights into how the hydrolyzed polyacrylamide (HPAM) polymer and Al 2 O 3 nanoparticles’ (NPs) hybrid can push crude oil toward the producers. An understanding of what the hybrid viscosity is when flowing through porous rocks was acquired by the rheological tests. Using the Du Noüy ring method, the interfacial tension (IFT) between the polymer nanohybrid and crude oil was studied. Contact angle experiments were employed to assess the ability of hybrid in reversing surface wettability. The results show that the hybrid can yield a 12% higher shear viscosity than the HPAM solution and the viscosity improvement dramatically depends on NPs’ concentration and temperature. With more than a 23% drop in the contact angle value, the results of contact angle experiments reveal the capability of the Al 2 O 3 NPs in altering surface wettability. The measured IFT between hybrid and crude oil at different temperatures demonstrates that the adsorption of NPs on the oil–aqueous phase interface can significantly improve the capillary number. This article not only presents the underlying mechanisms of oil recovery during hybrid flooding but also provides a new reference for formulating a novel hybrid agent.

Although diverse uranium (U) adsorbents have been explored, it is still a great challenge for high-efficient uranium extraction form seawater. Herein a wood-mimetic oriented porous Ti 3 C 2 T x -MXene/gelatin hydrogel (MGH) has been explored through growing directional ice crystals cooled by liquid nitrogen and subsequently forming pores by freeze-dry (Ice-template) method, for ultrafast and high-efficient U-adsorption from seawater with great enhancement by both electric field and sunlight. Different from disperse Ti 3 C 2 T x -MXene powder, this MGH not only can be easily utilized but also can own ultrahigh specific surface area for high-efficient U-adsorption. The U-adsorbing capacity of this MGH (10 mg) can reach 4.17 mg·g −1 after only 1 week in 100 kg of seawater, which is outstanding in existing adsorbents. Furthermore, on the positive pole of 0.4 V direct current source or under 1-sun irradiation, the U-adsorbing capacity of the MGH can increase by 57.11% and 13.57%, respectively. Most importantly, the U-adsorption of this hydrogel can be greatly enhanced by simultaneously using the above two methods, which can increase the U-adsorbing capacity by 79.95% reaching 7.51 mg·g −1 . This work provides a new biomimetic porous MXene-based hydrogel for electric field/sunlight bi-enhanced high-efficient U-extraction from seawater, which will inspire new strategy to design novel U-adsorbents and systems.

The effects of sputtering technological parameters (sputtering power, pressure, and time) on properties of stainless steel (SS)-sputtered polyester (PET) fiber were investigated. The variations in properties such as surface morphology, tensile strength, abrasion resistance, and electromagnetic shielding effectiveness of the prepared PET fiber sputtered under various parameters were discussed. The results indicated that the uniformity and denseness of the sputtered SS film were positively dependent upon the predetermined sputtering variables. The properties such as the breaking strength and abrasion resistance of SS-sputtered PET were remarkably enhanced as compared to the pristine one. It was found that the disorientation of macromolecules in fiber was mainly responsible for the deteriorated strength following wet and/or dry heating. In addition, a woven fabric composed of SS-sputtered fiber exhibited electromagnetic shielding capability. This research indicates that the metal deposition onto textile surfaces using magnetron sputtering is a straightforward approach for potential use in multifunctional materials.

In this study, a novel material of core–shell structured magnetic molecularly imprinted polymers (Fe 3 O 4 @SiO 2 @Au (FSA)-MIPs) was successfully prepared for the rapid and selective determination of 4-methylmethcathinone (mephedrone, 4-MMC). The adsorption capacity of FSA-MIPs is 34.7 mg·g −1 at 308 K, which is significantly higher than magnetic non-imprinted polymers profiting from the imprinting effect. The FSA-MIPs have a short equilibrium (20 min) and could be reused more than six times. Moreover, the selectivity coefficients of FSA-MIPs for 4-MMC, 3,4-dimethylmethcathinone, butylone, 4-ethylmethcathinone, acetylfentanyl, and methylene blue are 4.01, 5.65, 7.62, 12.30, and 20.87 respectively, further indicating the markedly enhanced binding selectivity of FSA-MIPs. As an adsorbent, the FSA-MIPs were successfully applied for effective extraction of 4-MMC in three human urine samples with the recovery rates ranging from 85.5–92.6%. The results confirmed that the FSA-MIPs have good prospects in the extraction and separation of synthetic cathinones, which is suitable for further application in the criminal sciences field.

Polymer blending is one of the most economical and effective techniques for achieving products with high comprehensive performances. However, the immiscibility between polymers results in a weak interface, which is typically the position where material failure starts when an external force is applied. Therefore, understanding and controlling the interfacial structure are important for controlling the failure behavior of polymer blends and achieving advanced materials. In this study, the related work was performed on a crystal/crystal blend of isotactic polybutene-1 and polyethylene (iPB-1/PE). The results indicated that iPB-1 and PE were partially miscible in a wide temperature window (140–220°C), and the phase separation of iPB-1/PE blends was retarded at 180°C, resulting in an increase in the interfacial thickness and interfacial adhesive strength when iPB-1/PE crystallized at a low temperature. In addition, the iPB-1/high-density PE (HDPE) samples exhibited higher interfacial adhesive strength than the iPB-1/linear low-density PE, which was attributed to the relative streamline chain structure and the wide molecular weight distribution of HDPE and improved the interpenetration, crystallization, and miscibility of iPB-1 and HDPE at the interface. During storage at room temperature, the interfacial adhesive strength of iPB-1/PE decreased because of the spontaneous crystal transition of iPB-1.

This study attempts to find a promising solution for the squeaking of ceramic on ceramic (COC) bearing surfaces by introducing reinforced poly(vinylalcohol) (PVA) layer-by-layer coatings on the bearing surface of Stryker Trident femoral head. A customized hip simulator was established to provide a realistic simulation of the normal gait (flexion–extension) of the hip joint, and to examine squeaking for coated and uncoated femoral heads. Different characterization techniques were employed to study the coatings’ structure. The PVA macromolecules were successfully cross-linked via epichlorohydrin agent, and chemically bonded onto the surface, forming a superior reinforced PVA coating on the femoral head’s surface. These coatings play a dominant role in increasing the pre-squeaking age of the hip joint due to reduction in hard-on-hard contact and femoral head liner clearance with their good viscoelastic properties. Which cause, damping friction-induced vibrations. This improvement resembles novel-type, long-life, and stable hip joint biomaterials with distinguished and promising pre-squeaking age.

Compacts of microcrystalline cellulose were prepared at applied compression pressures of 21, 32, 43, 53, and 64 MPa. Compacts were subjected to elevated temperatures of 125°C, 150°C, and 175°C according to a 5-min heating program. The effect of these thermal treatments on compact volumes, densities, porosities, tensile strengths, and weight loss was determined. There was no change in the volumes of the compacts due to thermal treatments in most of the conditions. However, the densities of the compacts decreased while the porosities increased as a consequence of weight loss. Moreover, there was no difference ( p > 0.05) between the tensile strengths of the compacts without heat treatment and those subjected to heat treatment in most of the conditions. This was indicative of the preservation of the magnitude of the interparticulate bonds in the compacts. Weight loss of the compacts was affected by the heat treatment temperature and their porosities.

Polyurethane-based retanning agents with antimicrobial properties were synthesized by the chemical incorporation of ciprofloxacin (CPFX) units into polyurethane chains. The chemical structures were characterized by Fourier transform infrared (FTIR) and gel permeation chromatography (GPC). Then, the retanning agents were applied in the leather retanning process. Owing to the conjugation of CPFX into polyurethane chains, the molecular weight increases, further leading to the decrease in hydroxyl value and increase in particle size. The shrinkage temperature was improved after retanning. Owing to the filling of retanning agents in the gap of collagen fibers, the average thickness of leather increased by 65.8%. The mechanical properties of leather were visibly improved because of the large number of –COOH coordinate with Cr 3+ and more hydrogen crosslinking with carboxyl group, amino group, and hydroxyl group of leather collagen. Furthermore, leather retanned by these polyurethane-based retanning agents presented good antimicrobial properties. The antibacterial activity could be conserved above 89% even after rinsing for ten times.

Spherical polyamide 12 (PA12) powder for selective laser sintering (SLS) was prepared by thermally induced phase separation (TIPS) method. It was authenticated that the mixed solvent can regulate the liquid–liquid phase separation (LLPS) process by changing the ratio of diluent to non-diluent. The polymer droplets mainly coalesced in the solution, and then the crystal nucleus of PA12 was formed in the droplets. Finally, high crystallinity PA12 powder was precipitated. The morphology, particle size distribution, thermal properties, the change of crystal structure, and powder spreading performances of the obtained powder were characterized. The powder had a narrow particle size distribution, an average particle size of 55.2 μm, and a broad sintering window of 29°C. The results exhibited that the powders prepared by TIPS had excellent sintering properties, and TIPS method provided more choices for SLS technology.

The application of pure polyvinyl alcohol (PVA) hydrogel as wound dressing faces many restrictions due to its insufficient elasticity, stiff membrane, and very limited hydrophilicity. These drawbacks can be limited through cross-linking with other natural biopolymers such as gum Arabic (GA). PVA hydrogels blended with six different GA concentrations were prepared. The characterization of these hydrogels was performed by Fourier transform infrared spectrophotometer, X-ray diffraction, and scanning electron microscope. The swelling ratio (% SR) percentage has been calculated. The possible cytotoxicity was determined using a sulforhodamine B assay. Wound healing test was performed on human skin fibroblast cells. Our results indicated that by increasing GA concentration in PVA hydrogel, the % SR increases and the cytotoxicity effect decreases. The results indicate also a significant gradual decrease in the wound area with time as the GA concentration increases in the PVA hydrogel. Therefore, GA improves the biological applications of PVA hydrogel.

Polyimide (PI) is widely used in the field of microelectronics because of its excellent thermal, mechanical, optical, and electrical properties. With the development of electronics and information industry, PI as a dielectric material needs to possess low dielectric loss. PI/carbon quantum dots (PI/CQDs) composite films with low dielectric loss were prepared by introducing CQDs into PI matrix. At 25°C and 1 kHz voltage, the dielectric loss of pure PI film is about 0.0057. The dielectric loss of PI/CQDs composite film is about 0.0018, which is about 68% lower than that of pure PI film. The dielectric loss of PI/CQD composite film is greatly reduced while the mechanical properties and thermal properties of PI/CQDs composite film roughly remain unchanged. Due to the cross-linking structure formed between CQDs and PI molecular chain, the relative movement of PI molecular chain is hindered.

The improvement of mechanical properties, electrical properties, and processing properties of ultra-high-filled thermal insulation polypropylene (PP) composites has been plagued by high filling amount of heat-conducting fillers such as alumina powder (Al 2 O 3 ) and expanded graphite. In order to improve its properties, this article uses a high-temperature-resistant coupling agent (A153) to modify the PP composite. The results of this study show that when the content of A153 reaches 7.5 phr, the tensile strength of PP composite can reach 5 MPa, the elongation at break can reach 25%, and the volume resistivity can reach 12.8 × 10 12  Ω·m, and the maximum thermal conductivity is 1.82 W·m −1 ·K −1 . The processability also shows that the introduction of A153 can increase the melt flow rate and effectively improve the processability of the material. Graphical abstract

The ceramifiable silicone rubber (SR) composite is prepared using boron oxide, calcium silicate, and kaolin as ceramifiable fillers. The effects of the content of CaSiO 3 /B 2 O 3 on the high-temperature properties of composites are investigated. In the process of decomposition and oxidation of the ceramifiable SR composite in air, B 2 O 3 , and low-melting-point glass frit that participate in the formation of the residue network structure in different temperature regions, it continuously produces a liquid phase during the process of the ceramifying transformation. Microscopic images reveal that different structures are formed at different temperatures. The network structure of the ceramic residue becomes increasingly compact with the increase in temperature from 600°C to 800°C, which has a better protective effect on heat transfer and mass loss. At 900°C, with the lattice reconstruction of calcium silicate and the change of crystal structure, volume expansion occurs after cooling, alleviating the volume shrinkage caused by ceramic phase formation in the process of ablation. When the ratio of CaSiO 3 /B 2 O 3 reaches 1:1 (both are 15 phr), the bending strength and linear shrinkage of the composites reach a satisfactory balance, the bending strength and the shrinkage reach 18.5 MPa and 12.1%, respectively.

Plant antioxidants can be applied in the management of various human diseases. Despite these, extraction of these compounds still suffers from residual solvent impurities, low recovery yields, and the risks of undesirable chemical changes. Inspired by the protein–lipid interactions in the cell membranes, we proposed using poly(styrene- alt -maleic acid) (PSMA) to destabilize and associate with the bilayer lipids into the membrane-like nanodiscs. Such nanostructures could serve as protective reservoirs for the active compounds to reside with preserved bioactivities. This concept was demonstrated in the antioxidant extraction from robusta coffee leaves. Results indicated that aqueous PSMA extraction (no buffer agent) yielded products with the highest contents of phenolic acids (11.6 mg GAE·g −1 ) and flavonoids (9.6 mg CE·g −1 ). They also showed the highest antioxidant activity (IC 50 = 3.7 µg·mL −1 ) compared to those obtained by typical sodium dodecyl sulfate and water extraction. This biomimetic approach could be considered for developing environmentally friendly extraction protocols in the future.

The marine pollution caused by traditional plastics is becoming increasingly serious, and the fundamental way to solve this problem is to look for plastic substitutes that can degrade in the marine environment. Herein, a series of high-molecular-weight poly(butylene succinate- co -diethylene glycol succinate) (PBDS) was obtained by the introduction of low-cost diethylene glycol (DEG) into the main chain of poly(butylene succinate) (PBS), which aimed to obtain the materials that can be degraded both in compost and seawater. The research showed that the increase in the DEG content reduced the crystallinity of the copolyester, which led to the decrease in mechanical strength and thermal properties of the copolyester to a certain extent. Meanwhile, the increase in hydrophilicity and the decrease in crystallinity improved the degradation rate of the material. Compared with PBS, PBDS exhibited not only a faster composting degradation rate but also a faster degradation rate in seawater. Graphical abstract Diethylene glycol-modified poly(butylene succinate) prepared copolyester, which can be degraded in seawater and compost at the same time, aiming to solve the problem of plastic pollution.

A ternary hybrid nucleating agent (THNA) powder was prepared by co-spray drying the fluid mixture of Si-MP/SNa slurry. The THNA was characterized by Fourier transform infrared and thermogravimetric analyses; the results showed that THNA was prepared successfully. The results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that THNA was ring-shaped or mushroom cap-shaped and it was uniformly dispersed in the iPP matrix. With the incorporation of THNA (0.2 wt%), the crystallization peak temperature of iPP/THNA increased effectively. The nucleation efficiency and crystallinity were improved to 69% and 58%, respectively. Moreover, the flexural strength, flexural modulus, tensile strength, and impact toughness of iPP/THAN were enhanced to 49.3 MPa, 1,988 MPa, 42 MPa, and 4.93 kJ·m −2 , respectively. The transparency was increased to 77.7%, and the haze was reduced to 14.1%. The compound of sodium laurate and inorganic silica/aromatic phosphate had an obvious synergistic effect.

Suzuki cross-coupling reaction was employed to easily obtain a triazine-based porous organic polymer (2,4,6-tris(5-bromothiophene-2-yl)-1,3,5-triazine [TBrTh]–1,3,5-benzene-triyltriboronic acid pinacol ester [BTBPE]–covalent triazine framework [CTF]) containing thiophene units. The chemical structure of TBrTh–BTBPE–CTF was revealed by solid-state 13 C NMR, Fourier-transform infrared, and X-ray photoelectron spectroscopy. TBrTh–BTBPE–CTF with an amorphous structure exhibited excellent thermal stability and intrinsic porosity (373 m 2 ·g −1 of Brunauer–Emmett–Teller surface area). Consequently, temozolomide (TMZ) was used as an oral alkylating agent in melanoma treatment to explore the drug loading and releasing behavior of TBrTh–BTBPE–CTF as a result of the low cytotoxicity of thiophene-based polymers. The successful loading of TMZ within the polymeric structure was suggested by thermogravimetric analysis and N 2 sorption isotherms. The release experiments were performed in phosphate-buffered saline at pH values of 5.5 and 7.4, exhibiting good controlled-release properties. These results suggest that the current porous organic polymer is expected to be a drug carrier for the delivery and release of TMZ.

Spherical polymer brushes were synthesized by grafting acrylamide from the surface of γ-methacryloxypropyl trimethoxy-silane-modified SiO 2 nanoparticles. Then, cationic spherical polyacrylamide (CSPAM) brushes were obtained by a manniched polyacrylamide (PAM). Fourier-transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, and gel permeation chromatography were introduced to analyze the structure, morphology, and molecular weight of CSPAM, respectively. The effects of pH and the dosage of CSPAM on the flocculation of fine pulp and precipitated calcium carbonate were studied. Furthermore, the optimal drainage performance could be achieved when the beating degree (°SR) decreased by about 14.42% with the dosage of CSPAM of 2 mg·g −1 . The retention effect of CSPAM revealed that the highest first-pass retention was 71.1% when the dosage of CSPAM was 3.5 mg·g −1 . In addition, the mechanism of retention and drainage of CSPAM was discussed.

The surface of nano-TiO 2 was modified by a silane coupling agent KH570, and the photosensitive resin was modified by blending the modified nano-TiO 2 with three-dimensional (3D) printing light-curing resin. The modified nano-TiO 2 powder was characterized by infrared spectrum, X-ray diffraction, contact angle test, and scanning electron microscope. The effects of different content of modified TiO 2 on the viscosity, curing shrinkage, tensile strength, elongation at break, hardness, thermal stability, and cross-section morphology of 3D printing photosensitive resin were studied. The results showed that the mechanical properties of epoxy resin were improved obviously after surface modification with a silane coupling agent. When the mass fraction of TiO 2 was 1.5%, the mechanical properties of the molded parts were the best. The tensile strength, impact strength, and elongation at break were increased by 51.1, 43.8, and 10.8%, respectively, and the hardness value was maintained at 81–83 HD. The addition of modified TiO 2 can improve the heat resistance of the epoxy resin. When the amount of TiO 2 is 1.5%, the T 50% , T max , and carbon residue rate of the epoxy resin are increased by 3.44°C, 6.34°C, and 25.3%, respectively.

The polymer with imine bonds (C═N) synthesized by condensation of aldehydes and amines was called polyimine. Graphene nanoplatelets (GNPs) were blended into polyimine by imine dynamic chemistry, and GNPs/polyimine (GNPs-P) composites were fabricated by heat-pressing. A series of thermal and mechanical properties have been tested for the matrix and GNPs-P composites. Thermogravimetric analyzer showed that the GNPs were able to improve the thermal stability of the GNPs-P composites. From the test of mechanical properties, GNPs-P composite with 0.5 wt% GNPs was superior to the matrix in bending and tensile properties. The bending and tensile strengths were 92.65 and 73.05 MPa, with an improvement of 18% and 5%. GNPs-P composites with 1 wt% GNPs showed the most significant advancement in impact properties, reaching an impact strength of 11.745 kJ·m −2 with a gain of 21.6%. Cross-sectional observations using scanning electron microscope proved that the GNPs-P composites have brittle fractures. A small number of GNPs could synergize with the matrix by bridging the cracks, creating a crack diffusion resistance and a load transfer reinforcement effect, which improved the mechanical properties of the GNPs-P composites.

The biodegradable composites were prepared by melt blending of chitosan (CS) and poly(butyleneadipate- co -terephthalate) (PBAT). By utilizing Fourier transformed infrared spectroscopy, scanning electron microscopy-energy dispersive spectroscopy, mechanical properties analysis, water contact angle measuring, differential scanning calorimetry, and thermogravimetric analysis, it was demonstrated that the CS of the PBAT-CS10 composite was relatively evenly dispersed in the PBAT matrix, the mechanical properties were significantly improved, the hydrophilicity was increased, the cold crystallization temperature was increased, and a good range of melt working temperature was obtained. The PBAT-CS10 composite was used to fabricate a cardiac occluder by fused deposition modeling of three-dimensional printing, and finite element analysis, and in vitro implantation testing proved the occluder’s mechanical support and sealing function under extreme boundary conditions. In vitro degradation experiments, neutral red uptake cytotoxicity assay, CCK-8 cell proliferation detection, immunofluorescence staining of the cytoskeleton, cell apoptosis detection, and reactive oxygen species assay were all performed on the composite, confirming that it and the occluder made of it could be hydrolyzed under physiological conditions and had no adverse effects on the cell membrane, lysosome membrane, cell proliferation, cell morphology, cell apoptosis, or ROS level, and had good biocompatibility.

Polylactic acid (PLA) and poly(3-hydroxybutyrate- co -4-hydroxybutyrate) (P(3HB- co -4HB)) nanofibers were prepared by melt extrusion of immiscible blends of PLA/polyvinyl alcohol (PVA) and P(3HB- co -4HB)/PVA via in situ formation of microfibrils during the melt extrusion process. The morphology of the blends and nanofibers after removal of PVA with water was studied using scanning electron microscopy. The intermolecular interactions in the blends were studied by Fourier-transform infrared spectroscopy. The compatibility of the components of the PVA/PLA blends was better than that of the PVA/P(3HB- co -4HB) blends. By varying the process conditions, the average diameter of the PLA nanofibers could be controlled in the range of 78–150 nm and that of the P(3HB- co -4HB) nanofibers could be controlled in the range of 274–424 nm.

Silicon carbide (SiC) was modified by melamine polyphosphate (MPP)-modified silicone to form SiC-MPP, then incorporated into epoxy resin (EP) for developing thermally resistant composites, which showed thermal conductivity and flame retardancy performance. The EP/SiC-MPP composites were prepared by blending and cured under 60°C for 2 h and 150°C for 8 h. The grafting degree of SiC-MPP was analyzed using Fourier transform Infrared, scanning electron microscope, and thermogravimetric measurements. The flame retardancy of the EP/SiC-MPP composites was studied by UL-94 vertical combustion and cone calorimetry test. The results showed that for EP/SiC-MPP containing 20 wt%, the UL-94 was case V1. Also compared to pure epoxy, the peak heat release rate (PHRR) of composites was reduced from 800 to 304 kW·m −2 . The thermal conductivity of EP/SiC-M20 composites was 0.53 W·m −1 ·K −1 , almost 2.5-fold higher than pure epoxy (0.21 W·m −1 ·K −1 ). The as-prepared EP/SiC-MPP composites exhibited enhanced flame retardancy and thermal conductivity. Based on analyses performed, these composites took credit-related applications.

Natural rubber latex/graphene nanoplatelet (NRL/GNP) composites containing GNP-pristine and GNP–SDS were prepared by a simple mechanical mixing method. The main objective was to study the effect of dispersibility of GNP on the properties in NRL. X-ray diffraction confirmed the adsorption of sodium sulfate dodecyl (SDS) on the GNP surface. The results showed that high filler loading diminished the physical and mechanical properties of the composites but successfully endured to satisfy electrical conductivity to the NRL/GNP composites. Besides, the SDS surfactant-filled system demonstrated better physical, tensile, electrical, and thermal stability properties than the GNP-pristine. The intercalated and dispersed GNP–SDS increased the number of routes for stress and heat transfer to occur and facilitated the formation of conductive pathways as well, leading to the improvement of the properties as compared to NRL/GNP-pristine composites. However, as the GNP–SDS loading exceeded 5 phr, the GNP–SDS localized in the interstitial layer of NRL, restricted the formation of crosslinking, and interfered with the strain-induced crystallization ability of the composites. Graphical abstract The effect of SDS in NRL/GNP–SDS composites.

The percolation thresholds of poly ether ether ketone/graphene (PEEK/Gr) composites in most studies are high due to the random distribution of Gr in the matrix. Here, aminated poly-ether-ether-ketone/graphene network (PEEK-NH 2 /GN) nanocomposites were prepared by electrostatic adsorption of PEEK-NH 2 with positive charges and graphene oxide with negative charges, followed by in -situ reduction and hot-pressing. The GN structure of composites was well presented in the images of scanning electron microscope. The PEEK-NH 2 /GN nanocomposites exhibited excellent electrical conductivity with a maximum conductivity of 0.0634 S·cm −1 and a percolation threshold as low as 0.25 vol%. In addition, the maximum tensile strength of nanocomposites was reached at 93 MPa when the Gr content was 0.5 wt%. We believe that this approach is a new avenue for the production of low filler high conductive polymer composites with potential commercial prospects in various fields.

By partially substituting 1,3,5-tris-(2-hydroxyethyl) cyanuric acid for glycerol as the polyol, new modified alkyd resins having a wide range of oil length and hydroxyl content were produced. FT-IR, 1 H NMR, acid and iodine values, and other characterization techniques were used to confirm the chemical compositions of the modified alkyd resins. The drying qualities of the alkyd resins synthesized were significantly enhanced by adding a greater quantity of freshly prepared polyol and excess –OH, along with improvements in flexibility, gloss measurement, gloss measurement, and scratch hardness, in comparison to unaltered alkyd resin (blank). The corrosion resistance of dried coated steel panels was examined using a salt spray test. By using a specifically designed modified alkyd resin as a binder, the corrosion resistance of painted steel panels was improved. The addition of the new polyol, which contains nitrogen components, as well as the alkyd resins that provide strong adherence to the steel surface, may be responsible for such an improvement.

The fabric defect models based on deep learning often demand numerous training samples to achieve high accuracy. However, obtaining a complete dataset containing all possible fabric textures and defects is a big challenge due to the sophisticated and various fabric textures and defect forms. This study created a two-stage deep pix2pixGAN network called Dual Deep pix2pixGAN Network (DPGAN) to address the above problem. The defect generation model was trained based on the DPGAN network to automatically “transfer” defects from defected fabric images to clean, defect-free fabric images, thus strengthening the training data. To evaluate the effectiveness of the defect generation model, extensive comparative experiments were conducted to assess the performance of the fabric defect detection before and after data enhancement. The results indicate that the detection accuracy was improved regarding the belt_yarn, hole, and stain defect.

The dry-type on-board traction transformer (DOBTT) has the characteristics of huge heat generation and high heat dissipation requirements, so it has higher requirements for heat dissipation performance of epoxy resin (EP) insulation. However, the toughness of the existing high thermal conductivity EP composite after being modified by inorganic particles is greatly reduced, and it is very easy to crack under the occasion of frequent vibration such as electric multiple units or electric locomotives, so it cannot be directly applied to the DOBTT. In this article, the composite using h-BN to improve the thermal conductivity, and epoxidized hydroxy-terminated polybutadiene (EHTPB) liquid rubber to improve the toughness was prepared. After characterization and testing, it was found that when the EHTPB content was between 10 and 15 phr, the elongation at break of the EP/h-BN/EHTPB composite could be increased by 47.9% and the impact strength could be increased by 47.8% compared with that without EHTPB. The thermal and electrical performances were still satisfactory, which has a potential in application of on-board electrical equipment.

The conformations and dynamic behaviors of wormlike chains confined by a slit in a pressure-driven flow were investigated using dissipative particle dynamics method. The wormlike chains exhibit varying conformations due to the varying shear stresses across the slit. The wormlike chain solution can be well described by the power-law fluid, and the power-law index decreases with the increase in chain rigidity. We also presented that the wormlike chain undergoes tumbling motion in the vicinity of the wall in the presence of pressure-driven flow. We also found that the wormlike chains can migrate both away from the wall and slightly away from the slit center, and the migration away from the slit center increases as the chain rigidity is increased because of hydrodynamic interactions induced in a more rigid wormlike chain.

We investigated the effect of starch modification on the mechanical properties of phenolic epoxy resin (EP). Corn starch admixture of 2.5, 5, 7.5, and 10 wt% were added into the EP. The tensile strength, elongation at break, and elastic modulus of different corn starch contents were compared. The containing of corn starch showed a positive effect on the toughness of the epoxy but showed little effect on strength when the additive content was less than 10 wt%. The strength and elastic modulus increased first and then decreased with the increase in starch content and reached their maximum values at a content of 2.5 wt%. The enhancement effect might be due to corn starch’s mechanical properties, dispersibility, and interfacial interaction. With the increase in starch content, starch granules quickly contact each other, causing self-aggregation sedimentation and a decrease in strength and elastic modulus. The scanning electron micrographs of the toughened EP specimens showed ductile failure because of the starch particles. The surface morphology of the blend resin specimens was full of staggered and stepped cracks caused by the shearing damage, which is shown by obvious plastic fracture characteristics with plastic deformation ability. The initiation of micro-cracks in the EP matrix was induced by the incorporation of starch particles, which caused localized stepped shear damage in the matrix. More energy would be absorbed during this process, and the toughness of the EP would be enhanced. It is recommended that the best corn starch content should be 2.5 wt% to obtain excellent strength and good toughness.

A semi-crystalline designated nylon 66 polymer is a crucial, high-performance engineering material that is used in wide variety of industrial applications including sensors, electrical insulators, electronic devices, and automotive sector. Using modules based on density functional theory and finite-field approaches, this work explores the optoelectronic and spectroscopic characteristics of this polymer. Absorption, dielectric function, refractive index, and optical conductivity are the principle topics of this study. The effects indicated that nylon 66 is a first-rate insulator and the degree of crystallinity estimated is 46.44%. The simulated bandgap vs. the Tauc relation value is greater than 7.0 eV and has a proportional inaccuracy of 2.36%. Absorption coefficient value, however, suggests that while the refractive index and dielectric function remain stable, the optical conductivity is elevated. In order to determine the advantages appropriate for many applications, this research develops a strong basis and perception of the linear and nonlinear optical properties of nylon 66.

Two novel bridged silsesquioxane (BSQ) precursors, 1,4-bis(trimethoxysilylpropylthioethenylphenoxy)benzene and 1,3-bis(trimethoxysilylpropylthioethenyl)benzene, were synthesized from arylacetylenes and 3-mercaptopropyltrimethoxysilane through the thiol-yne click reaction. Then, bridged polysilsesquioxane aerogels were prepared from BSQ precursors alone or together with tetramethoxysilane (TMOS) as a co-precursor through the sol–gel method. The resulted aerogels were characterized by scanning electron microscopy, mercury intrusion porosimetry, thermogravimetric analysis, transient hot-wire method, and water contact angle tests. Their mechanical properties were evaluated by unidirectional compression tests. The properties of the aerogels are strongly affected by precursor content, mass ratio of BSQ to TMOS, and the structures of BSQ. The obtained aerogels do not break even when compressive strain is up to 55% and show high compressive modulus (≥2.46 MPa) and hydrophobicity (water contact angle ≥130°). Graphical abstract

Reasonable design of inorganic nano-base materials to promote the anticorrosion performance of waterborne epoxy resin (EP) coating remains a great challenge. Herein, we describe the preparation method and anticorrosion properties of zeolitic imidazolate framework (ZIF-67) composite coatings. ZIF-67 could be used as both anticorrosion filler and pigment for the coatings. The addition of ZIF-67 improved the impermeability of the coating, thus slowing down the chemical reaction on the surface of the substrate. The long-term corrosion-resistant performance of composite coatings (ZIF-67@EP) in 3.5% NaCl solution was evaluated comparatively. Before immersion, the low-frequency impedance of 1% ZIF-67@EP coating was 2.5 times of 0% ZIF-67@EP coating, and after 14 days of immersion, the low-frequency impedance of 1% ZIF-67@EP coating was still 1.8 times of 0% ZIF-67@EP coating. The corrosion rate of 1% ZIF-67@EP coating was decreased by 177 times.

Nowadays, with the continuous understanding of the pathogenic mechanism of bacterium, the demand for antibacterial plastic products had significantly increased. Besides that, many counties issued mandatory standards for plastic products, which imposed strict requirements on ash content to prevent the addition of excessive inorganic matter to plastics in order to avoid weakening the properties of plastics and deteriorating the recyclable property. Based on this, the development of composites with organic fiber-loaded antibacterial agents is of practicable value and urgency. We used an open-ring addition reaction to modified aramid fiber (AF) by utilizing epoxypropyltrimethoxysilane to react with the reactive groups on the surface of AFs. Subsequently, the modified fibers were surface loaded with silver ionic glass beads. After that, a series of high-density polyethylene composites with excellent mechanical properties and antibacterial properties were prepared using melt mixing method. It was shown that the composite had a low ash value (1.88 wt%) even at a higher filling concentration (7 wt%) and the fibers could change the crystalline properties and morphology of the composite. Because of the fiber reinforcement and crystallization induction effects, the tensile strength and elasticity module of the composites could be improved by 141% and 136%, respectively. In addition, the composites had excellent long-lasting contact antibacterial effects against the inhibition of E. coli . The proposed organic fiber loading technique and antibacterial composites will provide a method for designing and preparing eco-friendly and high-performance plastic products.

In this study, the grafting of methyl methacrylate (MMA) in a solvent system containing nitrogen of pyridine onto LDPE films was performed using the post-irradiation technique in nitrogen at different gamma doses. The DG% obtained in MMA grafting was 71.0% at 10 kGy of γ dose was increased to 90% in (MMA/Py) (80/20 v/v%) system, indicating the existence of Py enhancement in the grafting % of MMA. The addition of pyridine (Py) into MMA matrix increases the molecular weight of the matrix due to the plasticizing effect of Py on the system. Morphological and structural changes in optical properties and thermogravimetric analysis were performed for the films. According to Fourier transform infrared data, a reaction may be placed between Py and MMA molecules. Furthermore, the effect of Py molecules on the optical properties of LDPE films is studied. The optical transition upon the grafting process increased, indicating the movement of the electrons due to intramolecular hydrogen bonds between MMA and Py molecules. The Urbach energy and the optical band gab, E g , were investigated and found to depend mainly on the grafting degree. The results obtained from E g calculations recommended using an irradiation dose of 15 kGy to get LDPE- g -MMA/Py films with suitable optical properties.

The Cr( vi ) ion-imprinted composite membranes (Cr( vi )-IICMs) were prepared by using the surface imprinting method. The template ion was Cr( vi ), the functional monomer was 4-vinylpyridine (4-VP), and the nylon filter membrane (nylon-6) was the support membrane. Non-imprinted composite membranes (NICMs) were prepared under the same conditions as the corresponding Cr( vi )-IICM. The adsorption effect of the imprinted membrane can reach 2.4 times that of the corresponding non-imprinted membrane. Meanwhile, the adsorption quantity of Cr( vi )-IICM was 34.60 μmol·g −1 . The physical characteristics of membranes were confirmed by Brunauer–Emmett–Teller and scanning electron microscopy. Inductively coupled plasma emission spectrometry was used to analyze their adsorption properties and permeation selectivity. Cr( vi )-IICM and NICM were both mesoporous materials from the structural characterization and performance test results. Their adsorption behavior conformed to the Langmuir isotherm adsorption model. The permeation recognition mechanism of Cr( vi )-IICM was the Piletsky’s gate model. The IICM still has excellent permeability selectivity to Cr( vi ) in the presence of competitive ions. The results provided a reference for the isolation and enrichment of Cr( vi ).

Hyaluronic acid (HA) is a biopolymer present in various human tissues, whose degradation causes tissue damage and diseases. The oxidized hyaluronic acid/adipic acid dihydrazide (oxi-HA/ADH) hydrogels have attracted attention due to their advantages such as thermosensitivity, injectability, in situ gelation, and sterilization. However, studies are still scarce in the literature as microcarriers. In that sense, this work is a study of oxi-HA/ADH microparticles of 215.6 ± 2.7 µm obtained by high-speed shearing (18,000 rpm at pH 7) as cell microcarriers. Results showed that BALB/c 3T3 fibroblasts and adipose mesenchymal stem cells (h-AdMSC) cultured on the oxi-HA/ADH microcarriers presented a higher growth of both cells in comparison with the hydrogel. Moreover, the extrusion force of oxi-HA/ADH microparticles was reduced by 35% and 55% with the addition of 25% and 75% HA fluid, respectively, thus improving its injectability. These results showed that oxi-HA/ADH microcarriers can be a potential injectable biopolymer for tissue regeneration applications.

A series of three-armed star polystyrene- block -poly( n -butylacrylate) copolymers (PS- b -PBA) 3 were synthesized to study the phase-transition behavior of the copolymers. The order-to-disorder transition temperature has been determined by oscillatory at different temperatures and dynamic temperature sweep at a fixed frequency. Moreover, the micro-phase separation in the block copolymers has been evaluated by time–temperature superposition, while the free volume and the active energy of the copolymers have been calculated. Interestingly, active energy decreased with the increase in the molecular weight of the PBA components. To further determine the order-to-disorder transition temperature precisely, small angle X-ray scattering was performed at different temperatures. These results confirm that the chain mobility of the star-shaped copolymers is strongly dependent on the arm molecular weight of the star polymers, which will be beneficial for the processing and material preparation of the block copolymers. Graphical abstract

The substitutions of the chlorine atoms in p -dichlorobenzene (DCB) or the chlorine end-groups of polyphenylene sulfide (PPS) by sodium N -methyl-4-aminobutyrate (SMAB) are important reactions in the polymerization of PPS. The reaction process of DCB with SMAB was studied under conditions similar to the polymerization of PPS. The molecular structures of the products were analyzed through high-performance liquid chromatography, liquid chromatography-mass spectroscopy, gas chromatography-mass spectrometry, and other methods. Several pairs of para - and meta -isomer products were found, which indicates the coexistence of both nucleophilic addition–elimination (S N2 Ar) mechanism and aryne intermediate mechanism. Based on mechanism analysis, the networks of reactions of DCB with SMAB were proposed and the effects of the ratio of SMAB to DCB, water content, and temperature on the reaction process were studied.

Removal of Cu 2+ ions from contaminated water is an important but challenging task. This study reports the synthesis of a composite hydrogel from two natural polysaccharides, namely, sodium alginate and chitosan, using inexpensive kaolin as a raw material and polyacrylamide as a modifier. The hydrogel had a high adsorption capacity and selectivity for Cu 2+ . The composite hydrogel was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The pseudo-second-order kinetic model was the most suitable model for the kinetic results, and the Langmuir isotherm model was the most representative of the sorption system. The results revealed that the adsorption process was mainly controlled by chemisorption. The maximum adsorption capacity of the adsorbent was 106.4 mg·g −1 . Therefore, this study presents a new perspective on the application of composite hydrogels as Cu 2+ adsorbents.

For controlling pathogenic bacteria using nanopolymer composites with essential oils, the formulation of chitosan/alginate nanocomposites (CS/ALG NCs) loaded with thyme oil, garlic oil, and thyme/garlic oil was investigated. Oils were encapsulated in CS/ALG NCs through oil-in-water emulsification and ionic gelation. The CS/ALG NCs loaded with oils of garlic, thyme, and garlic–thyme complex had mean diameters of 143.8, 173.9, and 203.4 nm, respectively. They had spherical, smooth surfaces, and zeta potential of +28.4 mV for thyme–garlic-loaded CS/ALG NCs. The bactericidal efficacy of loaded NCs with mixed oils outperformed individual loaded oils and ampicillin, against foodborne pathogens. Staphylococcus aureus was the most susceptible (with 28.7 mm inhibition zone and 12.5 µg·mL −1 bactericidal concentration), whereas Escherichia coli was the most resistant (17.5 µg·mL −1 bactericidal concentration). Scanning electron microscopy images of bacteria treated with NCs revealed strong disruptive effects on S. aureus and Aeromonas hydrophila cells; treated cells were totally exploded or lysed within 8 h. These environmentally friendly nanosystems might be a viable alternative to synthetic preservatives and be of interest in terms of health and food safety.

Poly(lactic acid)/poly(butylene adipate- co -terephthalate) with a content ratio of 90/10, and its calcium carbonate (CaCO 3 ) composites with nano- and micro-sized particles were prepared by melt mixing. The dependence of thermal and mechanical properties of the composites on the particle size and addition content of the CaCO 3 filler was investigated. The composite containing five parts micro-sized filler (abbreviated as 90 L 10 B 5m C, similarly hereinafter) exhibited α and α′ crystallines on cooling as 90 L 10 B without fillers. 90 L 10 B 11m C and 90 L 10 B 11n5m C exhibited only α′ crystalline, and the others exhibited no discernible crystalline. Jeziorny method showed that the crystallization mode of poly(lactic acid) chains in different composites was close, and Mo method showed that the crystal growth mode in 90 L 10 B 11n5m C was different from others. Changes in thermal and mechanical properties were attributed to the overall connection strength which was dependent on the particle size and addition content of the CaCO 3 filler. From the perspective of industrialization, 90 L 10 B 5n11m C was preferred.

Chitosan is an amino-polysaccharide, traditionally obtained by the partial deacetylation of chitin from exoskeletons of crustaceans. Properties such as biocompatibility, hemostasis, and the ability to absorb physiological fluids are attributed to this biopolymer. Chitosan’s biological properties are regulated by its origin, polymerization degree, and molecular weight. In addition, it possesses antibacterial and antifungal activities. It also has been used to prepare films, hydrogels, coatings, nanofibers, and absorbent sponges, all utilized for the healing of skin wounds. In in vivo studies with second-degree burns, healing has been achieved in at least 80% of the cases between the ninth and twelfth day of treatment with chitosan coatings. The crucial steps in the treatment of severe burns are the early excision of damaged tissue and adequate coverage to minimize the risk of infection. So far, partial-thickness autografting is considered the gold standard for the treatment of full-thickness burns. However, the limitations of donor sites have led to the development of skin substitutes. Therefore, the need for an appropriate dermal equivalent that functions as a regeneration template for the growth and deposition of new skin tissue has been recognized. This review describes the properties of chitosan that validate its potential in the treatment of skin burns.

Geopolymers emerge as an ecological alternative for construction materials. These consist of a mixture of aluminosilicate sources and an alkaline solution that dissolves the silicon and aluminum monomers that come from the source to generate a gel called N–A–S–H that will control the main properties of the geopolymer. The geopolymer stands out for having good resistance to compression, as well as good resistance to high temperatures and corrosive environments. They have great potential as a replacement for classical technologies such as concrete, however, require further applied research to determine their feasibility on an industrial scale.

The current review extensively discusses the effects of various natural fillers on mechanical, thermal, and tribological characteristics of polypropylene, polyethylene, poly(vinyl chloride), and polyester resin matrices. The discussion has considered all of the tensile, flexural, and impact properties along with the wear rate and thermogravimetric analysis of a wide range of natural reinforcements. Detailed comparative studies about the factors that influence the fillers’ performance in the polymeric composites were also conducted to give the reader a comprehensive understanding to enable a better selection of the optimized characteristics to develop a more sustainable design. This systematic review indicates that the majority of green fillers had an adverse effect on the tensile strength of the considered matrices, but generally improved the tensile modulus. Moreover, the studied fillers enhanced the flexural modulus property for all mentioned matrices. The impact strength was dramatically influenced by the intrinsic characteristic of the filler type.

Increasing concern for the environment has led researchers to pay more attention to the fabrication of polymer biocomposites for many different applications. Polymer biocomposites have generally been fabricated utilizing synthetic or natural polymers with natural fillers. Recently, ionic liquids have been used for the pretreatment of natural fillers prior to the fabrication of polymer biocomposites. In this mini-review, four types of ionic liquids used for the pretreatment of natural filler are classified, specifically chloride-, diethyl phosphate-, acetate-, and bistriflimide-based ionic liquids. In addition, the pretreatment processes of natural fillers with ionic liquids are described in this review. Furthermore, the influence of ionic liquid pretreatment on the physicomechanical properties of polymer biocomposites is succinctly reviewed. Besides, the information presented in this review contributes to a clearer understanding of the process of ionic liquid pretreatment and the vital physicomechanical properties of polymer biocomposites. In summary, most ionic liquid pretreatments can improve almost all physicomechanical properties of polymer biocomposites.

The current day target for material scientists and researchers is developing a wholesome material to satisfy the parameters such as durability, manufacturability, low cost, and lightweight. Extensive research studies are ongoing on the possible application of polymer matrix composites in engineering and technology, since these materials have an edge over conventional materials in terms of performance. Hybridization of reinforcements is considered to be a better option to enhance the efficiency and performance of composite materials. Accordingly, research studies focus on the surface treatment of natural fibers and the addition of nanofillers (natural or synthetic) by industry and academia to take the properties and application of composites to the next level. This review purely focuses on the influence of fillers on the properties of composites along with the probable application of filler-based polymer composites.

We propose a pressure-induced flow (PIF) processing method for the simultaneous enhancement of strength, toughness, and heat resistance of biodegradable poly(butylene succinate) (PBS). The pressure and temperature were systematically adjusted to optimize the tensile strength of PBS. Under the optimized processing conditions, the structured PBS was characterized by relatively high strength of 89.5 MPa, toughness of 21.4 kJ·m −2 , and improved heat resistance without deterioration of much of its ductility. Microscopic analyses witnessed denser and highly oriented crystalline domains along the flow direction caused by PIF processing. Detailed crystallization analysis made by 2D-WAXD and 2D-SAXS unraveled the extremely ordered PBS domains, which were featured by a significant increase in the orientation degree from 0.25 for the reference to 0.73 for PIF-processed PBS. Such a highly ordered microstructure substantially boosted the degree of crystallinity and heat-resistance temperature of PBS. We believe that our findings would offer a facile, green, and cost-effective approach for fabricating biodegradable polymers with outstanding properties and performance.

It is a major challenge to prepare commercially viable scale semifluorinated liquid-crystalline block copolymers (SEFL-BCPs) using solution processing techniques. The technology of selectively solvating one block in a suitable solvent to realize self-assembly provides a promising route for the preparation of core-corona block polymer materials with extensive potential applications. However, considerable limitations have been discovered after much practice. BCP assemblies often require a separate synthesis step and are performed at high dilution. Herein, a one-pot approach combining polymerization-induced and crystallization-driven self-assembly (PISA-CDSA) was used to obtain well-defined, precise compositions of SEFL-BCPs. It is first synthesized via reversible addition-fragmentation chain transfer ethanol dispersion polymerization between 1 H ,1 H ,2 H ,2 H -heptadecafluorodecyl acrylate and poly( N,N -dimethylacrylamide) at a concentration up to 20% v/v. Various morphologies, including 1D fiber-like micelles, 2D lamellar structures, and fusion structures, were first observed via transmission electron microscopy. This scalable PISA-CDSA strategy is greatly expanding the morphology scope and applicability of the polymer liquid crystal materials science field.

Poly(ionic liquids) (PILs) exhibit better durability, processability, and mechanical stability than ionic liquids. PIL self-assembly in green solvents is a well-established strategy for preparing polyelectrolytes. Reversible addition-fragmentation chain transfer (RAFT) polymerization-induced self-assembly (PISA) has proven to be the most controllable method for synthesizing polyelectrolytes. However, there have been few reports on preparing high-order morphology PILs by RAFT-PISA. A new type of ionic monomer, 1-butyl-3-(4-vinylbenzyl)imidazolium hexafluorophosphate ([BVBIm][PF 6 ]), was prepared from substitution reaction and ion exchange reaction of 1-butylimidazole and 4-vinylbenzyl chloride. Herein, various morphologies, including spheres, worms, and vesicles, were easily obtained via RAFT ethanolic dispersion polymerization using poly( N , N -dimethylacrylamide) (PDMA 43 ) as the macromolecular chain transfer agent and [BVBIm][PF 6 ] as the monomer. Dispersion polymerization kinetic experiments, dynamic light scattering, transmission electron microscopy, and differential scanning calorimetry were used to investigate the PDMA 43 - b -P([BVBIm][PF 6 ]) x block nanoparticles. This efficient RAFT-PISA method for preparing functionalized PIL nano-objects with controlled morphologies represents significant progress in this field. Graphical abstract

In recent years, with the rise of an intelligent concept, oral and maxillofacial surgery smart dressing had also attracted the interest of researchers, especially for the pH sensor with flexible medium. In this study, polyvinylidene fluoride (PVDF) nanofibrous yarn was fabricated by a conjugate electrospinning process and modified with in situ polymerization of polyaniline (PANI) forming a PANI/PVDF yarn. By a weaving process, these yarns could be weaved into a fabric. It was found that both the PANI/PVDF yarn and the fabric showed a sensitivity to pH, about −48.53 mV  per pH for yarn and −38.4 mVper pH for fabric, respectively, in the pH range of 4.0–8.0. These results indicated that the prepared PANI-modified PVDF yarn and fabric might have a potential application in intelligent oral and maxillofacial surgery dressings for monitoring wound healing.

Graphene is one of most exceptional type of nanocarbon. It is a two-dimensional, one atom thick, nanosheet of sp 2 hybridized carbon atoms. Graphene has been employed as nanofiller for shape memory polymeric nanocomposites due to outstanding electrical conductivity, mechanical strength, flexibility, and thermal stability characteristics. Consequently, graphene nanostructures have been reinforced in the polymer matrices to attain superior structural, physical, and shape recovery properties. This review basically addresses the important class of shape memory polymer (SMP)/graphene nanocomposites. This assessment is revolutionary to portray the scientific development and advancement in the field of polymer and graphene-based shape memory nanocomposites. In SMP/graphene nanocomposites, polymer shape has been fixed at above transition temperature and then converted to memorized shape through desired external stimuli. Presence of graphene has caused fast switching of temporary shape to original shape in polymer/graphene nanocomposites. In this regard, better graphene dispersion, interactions between matrix-nanofiller, and well-matched interface formation leading to high performance stimuli-responsive graphene derived nanocomposites, have been described. Incidentally, the fabrication, properties, actuation ways, and relevance of the SMP/graphene nanocomposite have been discussed here. The potential applications of these materials have been perceived for the aerospace/automotive components, self-healing nanocomposites, textiles, civil engineering, and biomaterials. Graphical abstract

Dynamic covalent bond-based shape memory polymers (DCB-SMPs) are one of most important SMPs which have a wide potential application prospect. Different from common strong covalent bonds, DCBs own relatively weak bonding energy, similarly to the supramolecular interactions of noncovalent bonds, and can dynamically combine and dissociate these bonds. DCB-SMP solids, which can be designed to respond for different stimuli, can provide excellent self-healing, good reprocessability, and high mechanical performance, because DCBs can obtain dynamic cross-linking without sacrificing ultrahigh fixing rates. Furthermore, besides DCB-SMP solids, DCB-SMP hydrogels with responsiveness to various stimuli also have been developed recently, which have special biocompatible soft/wet states. Particularly, DCB-SMPs can be combined with emerging 3D-printing techniques to design various original shapes and subsequently complex shape recovery. This review has summarized recent research studies about SMPs based on various DCBs including DCB-SMP solids, DCB-SMP hydrogels, and the introduction of new 3D-printing techniques using them. Last but not least, the advantages/disadvantages of different DCB-SMPs have been analyzed via polymeric structures and the future development trends in this field have been predicted.

This research constructs an esterase-responsive hyperbranched polyprodrug nano pharmaceutical and investigates their antitumor activity. Polyprodrug micelle was prepared by one-pot method based on glutathione (GSH), doxorubicin (DOX), and polyethylene glycol (PEG) under the catalyst of N , N -dicyclohexylcarbodiimide (DCC), 4-dimethylaminopyridine (DMAP), and 1-hydroxybenzotriazole (HOBt). The polyprodrug was characterized by nuclear magnetic resonance (NMR), Fourier transform infrared spectrometer (FT-IR), ultraviolet-visible spectrophotometer (UV-Vis), dynamic light scattering (DLS), and transmission electron microscope (TEM), respectively. The antitumor activity of polyprodrug micelle was evaluated by Hela cell and the distributions of micelles in cells were observed by fluorescent microscope. The NMR and FT-IR confirmed that the DOX-GSH-PEG polyprodrug was successfully synthesized. The drug loading rate is 10.21% and particle size is 106.4 ± 1 nm with a narrowed polydispersity (PDI = 0.145). The DLS showed that the micelles were stable during 7 days at 25°C. The drug release results showed that the micelles could be esterase-responsive disrupted, and the drug release rate could reach 43% during 72 h. Cell uptake and cell viability demonstrated that the micelles could distribute to cell nuclei during 8 h and induce cell apoptosis during 48 h. Overall, these hyperbranched polyprodrug micelles prepared by one-pot method could be esterase-responsive disrupted and release the antitumor drugs in a high esterase environment for cancer therapy in vitro . These results confirm that DOX-GSH-PEG is an effective nanomedicine in vitro and the endogenous-based strategy with one-pot synthesis to construct esterase-responsive polyprodrug would probably be a preferred choice in the future.

Building long-lasting antimicrobial and clean surfaces is one of the most effective strategies to inhibit bacterial infection, but obtaining an ideal smart surface with highly efficient, controllable, and regenerative properties still encounters many challenges. Herein, we fabricate an ultrathin brush–hydrogel hybrid coating (PSBMA-P(HEAA- co -METAC)) by integrating antifouling polyzwitterionic (PSBMA) brushes and antimicrobial polycationic (P(HEAA- co -METAC)) hydrogels. The smart bacterial killing–releasing properties can be achieved independently by the opposite volume and conformation changes between the swelling (shrinking) of P(HEAA- co -METAC) hydrogel layer and the shrinking (swelling) of PSBMA brushes. The friction test reveals that both METAC and SBMA components support great lubrication. By tuning the initial organosilane (BrTMOS:KH570) ratios, the prepared PSBMA-P(HEAA- co -METAC) coating exhibits different antibacterial abilities from single “capturing–killing” to versatile “capturing–killing–releasing.” Most importantly, 99% of the bacterial-releasing rate can be easily achieved via 0.5 M NaCl treatment. This smart surface not only possesses long-lasting antibacterial performance, only ∼1.09 × 10 5 cell·cm −2 bacterial residue even after 72 h exposure to bacteria solutions, but also can be regenerated and triggered between water and salt solution multiple times. This work provides a new way to fabricate antibacterial smart hydrogel coatings with bacterial “killing–releasing” functions and shows great potential for biomedical applications.