Simultaneous improvement of interfacial bonding and thermal resistance of carbonaceous fiber/silicone composite coatings modified with aniline-methyl-triethoxysilane

Mechanical properties and thermal resistance reinforcement were achieved by a one-step dipping method, in which an aniline-methyl-triethoxysilane (AMT) coupling agent was grafted onto the carbonaceous fiber (CF) to fabricate CF/silicone resin (SR) composite coatings. Micromorphology and structure analysis of carbonaceous fibers showed that the AMT modification increase the roughness and the uniformity on the fiber surface, resulting in the link between AMT and fiber surface, and the polysiloxane formation by polymerization between the Si-OH groups. The AMT modification of the fiber surface introduced the AMT with a disordered structure on the fiber surface and improved the compatibility between CFs and SR. Mechanical testing showed that the tensile strength and elongation rate of the coating containing CF modified with 1wt%AMT coupling agent was increased by 45.32 % and 19.07 % compared with that of the unmodified one, respectively. The reinforcing mechanism revealed that the AMT modification improved interfacial bonding and mechanical riveting. Besides, the thermogravimetric analysis (TGA) analysis showed that the siloxane layer crosslinked at a high temperature, which was conducive to improving the thermal resistance for the long-term stability of the composite coatings. This special treatment provides an idea for simultaneously improving the mechanical properties and thermal resistance of silicone composites.