Effects of silane and silica enrichment of carbon fibers (CFs) on interfacial properties of methylphenylsilicone resin (MPSR) composites were investigated. CFs were oxidized, grafted with 3-aminopropyltriethoxysilane (APS) and then modified with silica nanoparticles prepared by the sol-gel polymerization of tetraethoxysilane (TEOS). Chemical structures of CFs were characterized by confirming the successful grafting. Scanning electron microscopy (SEM) showed a uniform distribution of silica nanoparticles on the CFs surface. The interlaminar shear strength (ILSS) and impact toughness of silanized CF (CF-Siloxane) composites were 12.05% and 7.46% higher than those of untreated composites. However, ILSS and impact toughness of the hybrid fiber (CF/Si) composites obtained from the hydrolysis of different concentrations TEOS improved significantly, especially for grafting silica enrichment with the TEOS concentration of 0.05 mol/L (CF/Si0.05), increasing 45.64% in ILSS and 29.59% in impact properties. Moreover, the hydrothermal aging resistance was also improved greatly. Meanwhile, functionalization processes did not decrease fiber tensile strength .
Jiajun Ma,Zongwei Guo,Shengtao Dai,Yannong Liu,Huiru Hu,Peikun Li,Lin Jin,Yuhui Ao
Inducing highly oriented 2D nanosheets to create a mussel-inspired interface phase on the carbon fiber (CF) surface to enhance its composites’ strength and toughness has become a great challenge. In this study, a novel coating was synthesized to induce the graphene oxide (GO) oriented distributed on the CF surface while constructing a biomimetic "Brick-and-Mortar" structural interface phase, which simultaneously promoted the strength and toughness of CF composites . Acting as a sizing agent, di-pyrene terminated PEG (py-PEG-py) facilitates abundant π-π* stacking interactions, and enables flexible chain segment motion during interface fracture of composites, as well as effectively improving the toughness of composites. Eventually, the formation of a superior mechanism on the CF surface results in remarkable properties for composites, including an interfacial shear strength (IFSS) of 99.3 MPa, interlaminar shear strength of 93.2 MPa, and flexural strength of 1430 MPa. The tensile strength and toughness increased to 1777 MPa and 45.0 MJm −3 , respectively. Simultaneously, the continuous thermal conduction pathway produced by the oriented attachment of GO on the CF surface increased in-plane thermal conductivity . The reinforcing mechanisms of the unique mussel-inspired coating were systematically investigated. This work opens up an effective and scalability avenue for obtaining high-performance CF composites.