Volume 40, Issue 5

Redox-active polymers among the energy storage materials (ESMs) are very attractive due to their exceptional advantages such as high stability and processability as well as their simple manufacturing. Their applications are found to useful in electric vehicle, ultraright computers, intelligent electric gadgets, mobile sensor systems, and portable intelligent clothing. They are found to be more efficient and advantageous in terms of superior processing capacity, quick loading unloading, stronger security, lengthy life cycle, versatility, adjustment to various scales, excellent fabrication process capabilities, light weight, flexible, most significantly cost efficiency, and non-toxicity in order to satisfy the requirement for the usage of these potential applications. The redox-active polymers are produced through organic synthesis, which allows the design and free modification of chemical constructions, which allow for the structure of organic compounds. The redox-active polymers can be finely tuned for the desired ESMs applications with their chemical structures and electrochemical properties. The redox-active polymers synthesis also offers the benefits of high-scale, relatively low reaction, and a low demand for energy. In this review we discussed the relationship between structural properties of different polymers for solar energy and their energy storage applications.

For hindered phenol (HP)/polymer-based hybrid damping materials, the damping properties are greatly affected by the structure variation of HPs. However, the unclear relationship between them limits the exploitation of such promising materials. Therefore, three HPs with different chain polarity were synthesized to explore the relationship in this paper. The structures of the HPs were firstly confirmed by Nuclear Magnetic Resonance Spectrum, Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray Diffraction (XRD). For further prepared HP/polyurethane hybrids, FT-IR and XRD were also adopted to confirm the hydrogen bonding interactions and micromorphologies. And, Molecular dynamics simulation was further used to characterize the effects of polarity variation on the hydrogen bonding interactions and chain packing of the hybrids in a quantitative manner. Then, combined with dynamic mechanical analysis, the relationship between the chain polarity variation of the hindered phenols and the damping properties was established.

The flax and equivalent proportion of poly( L -lactic acid)/poly( d -lactic acid) (PLLA/PDLA) were melt compounded and injection molded to prepare flax reinforced polylactide stereocomplex (sc-PLA) bio-composite, and two different coupling agents, hexamethylene diisocyanate (HMDI) and maleic anhydride grafted polypropylene (MAPP), were used to modify the interface of composite, then the influence of different interfacial modification on the structure and properties of composite was investigated. The results showed HMDI modification decreased the total crystallinity of composite but promoted the formation of stereocomplex crystallites (sc), whereas MAPP modification could improve both the total crystallinity and sc crystallinity. HMDI modification significantly improved the interfacial compatibility of composite, and thereby effectively improved the tensile strength and initial storage modulus of composite. By contrast, the interfacial compatibility of flax/sc-PLA composite was weakened by MAPP modification. Although the tensile properties of flax/sc-PLA/MAPP composite decreased, the impact strength of composite was increased by 12.1% than the unmodified composite. Therefore, the tailored flax/sc-PLA composite with varying properties could be prepared by different interfacial modification.

Poly (butylene succinate-co-butylene-3-hydroxyphenylphosphinyl-propionate) (PBSH) was synthesized through polycondensation. Then, 4,4′-methylene diphenyl diisocyanate (MDI) was introduced into PBSH matrix by reactive blending. The chemical structure and properties of the blending products were investigated using Fourier Transform Infrared Spectroscopy (FT-IR), differential scanning calorimetry (DSC), limiting oxygen index (LOI) tests, thermogravimetric analysis (TGA), and vertical burning tests. The results proved that MDI can improve the mechanical properties and flame retardancy of PBSH. In addition, it was found that the crosslinking structure can reduce the hydrolysis rate of PBSH and effectively eliminate the melt-dripping of PBSH during combustion.

The interfacial interaction between the fiber and matrix is the most important factor which influences the performance of the carbon fiber-epoxy composites. In this study, the graphitic surface of the carbon fibers was modified with graphene oxide nanomaterials by using a spray coating technique which is an easy, cheap, and quick method. The carbon fiber-reinforced epoxy matrix composites were prepared by hand layup technique using neat carbon fibers and 0.5, 1 and 2% by weight graphene oxide (GO) modified carbon fibers. As a result of SEM analysis, it was observed that GO particles were homogeneously coated on the surface of the carbon fibers. Furthermore, Young's modulus increased from 35.14 to 43.40 GPa, tensile strength increased from 436 to 672 MPa, and the elongation at break was maintained around 2% even in only 2% GO addition.

This work reports the fabrication and characterizations of porous scaffold made up of polylactic acid (PLA) with the inclusion of pectin (1, 3, 5, 7, 9, 11 wt%) for potential tissue engineering material. The composite scaffold was prepared using a facile method of freeze extraction. Based on the physical evaluations, the scaffold was suggested to be optimum at 5 wt% of pectin loading. Water contact angle of the scaffold was significantly reduced to 46.5 o with the inclusion of 5 wt% of pectin. Morphological and topographic of the PLA scaffold revealed that the pectin induced more porous structure and its surface became rougher which was suitable for cell attachment and proliferation. In vitro studies of the PLA/pectin composite scaffold using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromidelt (MTT) assay revealed good biocompatibility whereas Live-Dead kit assay resulted in 91% cell viability after 7 days of incubation.

Induction welding is an important joining technique with potentially significant application in the connection of the Poly Ether Ether Ketone (PEEK). The present research employs the metal mesh as induction components into the induction welding of PEEK plate to PEEK plate at low power successfully. Besides, the examinations and analyses of macro/micro-structures, energy dispersive spectroscopy (EDS) and mechanical tensile properties of the joints are conducted. Meanwhile, the characteristics and formation mechanisms of the lap-welded interface structures are interpreted in detail. The results indicate that the interface morphology of the welded joint is of high quality at low power, which most of the interface area is tightly connected due to the element diffusion. Besides, the connection mechanism of the joint is bonding connection and mechanical engagement, which plays a major role in a great performance joint. Furthermore, the tensile fracture of the joint occurs in the heat-affected zone, which contributes to a high joint tensile strength.

In this paper, the β-cyclodextrin (β-CD) and biotin (Bi) were successfully grafted onto carboxymethyl chitosan (CMCS). And then the β-CD-Bi-CMCS nanoparticles (NPs) were prepared as oral nano-delivery carrier of protein drugs by ionic gelation method. The morphological feature of fabricated drug carrier was determined by dynamic light scattering and transmission electron microscopy. The result showed that the prepared NPs presented spherical structure with an average diameter of 138 nm. Bovine serum albumin (BSA) was selected as model protein drug that was entrapped in prepared drug carrier with satisfactory entrapment efficiency (79.18%) and loading content (3.96%). The drug release profiles of BSA/β-CD-Bi-CMCS NPs were studied at different pH environment for simulated gastric fluid (SGF), simulated intestinal fluid (SIF) and simulated colonic fluid (SCF). It was found that the BSA/β-CD-Bi-CMCS NPs displayed a pH dependent drug release profiles. After 72 h, the cumulative release amount of BSA in SGF, SIF, and SCF was about 20.57, 74.46, and 91%, respectively. Furthermore, the enzymatic degradation and cytotoxicity studies showed the synthesized β-CD-Bi-CMCS NPs had high chemical stability and biocompatibility. This work indicated that the β-CD-Bi-CMCS NPs had the potentiality as promising nanocarriers for oral delivery of protein drugs.