Surface modified UHMWPE fibers with functional interfacial layers: a strategy for enhanced composite interfacial and mechanical performance

Ultra-high molecular weight polyethylene (UHMWPE) fiber is prized for the superior strength and modulus. Nevertheless, the smoothness of fiber surface and the absence of polar functional groups in polymer backbone result in poor interfacial adhesion with matrix of composites. This severely decreases the mechanical performance and impedes the practical applications of UHMWPE fiber-reinforced composites. To optimize the interfacial compatibility between UHMWPE fiber and matrix, a series of amphipathic polymer brush PVA-OCT oligomer and multi-armed molecule DiPE-OCT with various functional groups herein as interfacial modification agents were synthesized. These functional groups form tight interaction with UHMWPE fiber and matrix through the mechanical interlocking and hydrogen bonding interactions, respectively. After modification by interfacial modification agents, UHMWPE fiber-reinforced composites exhibited a significant enhancement in the interfacial bonding and mechanical properties. Notably, an enhancement of 158.1 % in interfacial shear strength (6.35 MPa) was achieved in modified UHMWPE fiber-reinforced epoxy composites compared to the control composite. Meanwhile, the flexural and tensile strengths of modified composites increased by 107.4 % and 53.3 %, respectively. Consequently, this study provides a facile and innovative method for the surface modification of UHMWPE fiber and remarkably reinforces UHMWPE fiber composites, actuating the industrial application of UHMWPE fiber composites.