High‐performance fiber‐reinforced composites with a polydopamine/epoxy silane hydrolysis‐condensate bilayer on surface of ultra‐high molecular weight polyethylene fiber

Abstract A bilayer structure with polydopamine (PDA) transition layer and 3‐glycidyl ether oxy‐propyl trimethoxy silane (GOPTS) hydrolysis‐condensate strengthened layer on the surface of ultra‐high molecular weight polyethylene (UHMWPE) fiber is prepared to improve the damage resistance of composites and more efficient stress transmission in composites. PDA is covered on the surface of UHMWPE fiber and then GOPTS is hydrolyzed and condensed to form inorganic ‐O‐Si‐O‐ with epoxy groups on the PDA layer. In addition, the surface activated nano‐SiO 2 is dispersed in the epoxy resin to increase the strength of the matrix resin. The results show that the interfacial shear strength (IFSS), the impact strength, the flexural strength and flexural modulus of UHMWPE‐PDA‐GOPTS/EP‐SiO 2 increase by 99.1%, 54.1%, 76.8%, and 36.6% respectively compared with unmodified UHMWPE/EP. The chemical compositions of the treated fiber surface are characterized by X‐ray photoelectron spectroscopy and Fourier transform infrared spectroscopy (ATR‐FTIR). With the help of the scanning electron microscopy, the interface failure and reinforcement mechanism of the composites are further explored due to UHMWPE fiber shear yield deformation, UHMWPE fiber fracture, matrix resin cracking and the relative sliding friction between the fiber and matrix.