Designing advanced fiber-reinforced polymer composites through biological inspiration proved to be a crucial strategy for overcoming limitations in simultaneously enhancing the strength and toughness of composites. To achieve simultaneous improvement in the interfacial strength and toughness between carbon fiber (CF) and epoxy, a spider silk-inspired interphase featuring hybrid interaction was constructed by introducing hyperbranched polyamide-amine (HPAA) and graphene oxide (GO) onto the surface of CF. The results suggested that manipulating the feed ratio to adjust the branching degree of HPAA allowed for the attainment of various hydrogen bond densities. The fiber surface with high hydrogen bond density provided more hydrogen bond interaction sites to promote the deposition of GO. Benefitting from the ameliorative interfacial adhesion force, surface energy and interface thickness, impressive improvements of 94.5 % and 110.0 % in respective interfacial strength and fracture toughness over those of untreated CF/EP composites were achieved for functionalized CF/EP composites. The enhancement mechanism of interfacial performance was attributed to the formation of a “nano-fishnet” structure, which improved the stress transformation efficiency and consumption of external energy absorbed by hydrogen bonds. The method of regulating the branching degree of hyperbranched polymers and hydrogen bond density has opened an advanced way for surface modification of high-performance fibers.
Series of Waterborne Polyurethanes (WPUs) were synthesized by molecular structure design, using sodium 2-((2-aminoethyl) amino) ethanesulfonate (AAS) as the post-chain extender, and selecting poly-1,4-butanediol adipate (PBA) and isophorone diisocyanate (IPDI) as the soft segment and hard segment, respectively. The effects of changes in PBA molecular weight and AAS content on the properties of WPUs were investigated through analysis of adhesion, mechanical properties , and thermal properties. The result showed that the T-peel strength , shear strength , and adhesion of the film reached 7.75 ± 0.48 N/mm, 1.81 ± 0.08 MPa, and 1.45 ± 0.11 MPa, respectively, due to the higher hydrogen bond density in the molecular structure when the Mn of PBA was 2000 g/mol. Based on the selection, the introduction of sulfamate increased the urea bond content of the system, further increasing the intramolecular hydrogen bond density. When the content of AAS was 1.0 wt%, the T-peel strength, shear strength, and adhesion of the film were increased to the highest values of 10.63 ± 0.30 N/mm, 2.08 ± 0.09 MPa, and 2.41 ± 0.08 MPa, respectively. Therefore, WPU has a wide range of applications in the field of water-based ink binders due to its high adhesive strength.
Xianfeng Guan,Wanzhen Wu,Shuyu Zhang,Guangpeng Ma,Xinpu Zhou,Cuicui Li,Di Yu,Yu Luo,Shuang Wang
ABSTRACT Achieving the right balance between electrical conductivity and long-term reliability in high-temperature proton exchange membrane (HT-PEM) technologies contributes to sustainable energy recycling. This study involves a groundbreaking effort to create amphiphilic polybenzimidazoles by incorporating 2-isocyanatopyridine into hydroxy-polybenzimidazole (OHPBI). A high hydrogen-bond density network is constructed through two-by-two interactions between the hydroxyl group, the imidazole molecule and quaternary ammonium group. Quaternary ammonium polymeric ionic liquid is introduced to maintain high phosphoric acid (PA) doping and PA retention. The PA retention of the amphiphilic polybenzimidazole membrane is 87.5% after 240 h at 160 °C/0% RH. Furthermore, the peak power density of the amphiphilic polybenzimidazole membrane reach 837.8 mW cm -2 at 180 °C and the voltage decay rate is 0.23 mV h -1 after long-term operation. More specifically, the amphiphilic polybenzimidazole membranes show a conductivity of 138.9 mS cm -1 at 180 °C. This indicates that the amphiphilic polybenzimidazole membrane has both high power output and long-term stability. This work introduces an innovative method to improve the efficiency of PBI-based HT-PEM.
危险品化学品经营许可证（带存储）