Largely enhanced mechanical and dielectric properties of paper-based composites via in situ modification of polyimide fibers with SiO2 nanoparticles

In this study, SiO2 nanoparticles were in situ grown onto the surfaces of polyimide fibers via sol–gel synthesis and the corresponding paper-based composites were fabricated by wet-forming process using the as-obtained fibers as the starting materials. A simultaneous enhancement of the tensile and tearing index as well as the interlayer bonding strength of paper-based composites could be achieved with an increment of 17.7%, 17.2% and 50%, respectively. What is more, the dielectric strength of the resultant composites increased by 127% compared with the pristine paper-based composites. The results indicated that the SiO2 nanoparticles could be used as an excellent interfacial linker between the fibers and polymer matrix, and a smart cushion to release interior and exterior applied forces. Besides, satisfactory results on thermal stability of paper-based composites were attained after coated with SiO2 nanoparticles.