Research on Interface Strengthening and Mechanical Properties of UHMWPE Fiber Composites Modified by Rigid‐Flexible Coating and Resin Esterification

To address the poor interfacial adhesion of ultra‐high molecular weight polyethylene (UHMWPE) fibers caused by their inherent surface inertness, this study presents a dual modification strategy: esterification of the polyethylene resin and construction of a “rigid‐flexible” coating on the fiber surface. The “flexible” coating was formed by tannic acid (TA) and tetraethylenepentamine (TEPA) via oxidative polymerization, followed by the introduction of amino‐functionalized nano‐silica (N‐SiO 2 ) as a rigid component. The results show that the modified resin can achieve good compounding with the fibers. The stable coating could significantly regulate the surface roughness of the fibers and greatly enhance the adhesion between fibers and resins. Under the optimal conditions (TA:TEPA mass concentration ratio = 2:3, treatment time = 6 h), the interlaminar shear strength, tensile strength, flexural strength, and low‐speed impact toughness of the composites increased by 19.52%, 22.54%, 27.55%, and 25.11%, respectively, compared to the unmodified specimens. Incorporation of nano‐SiO 2 further enhanced these mechanical properties. This research provides theoretical and technical inspirations for the functional development of UHMWPE fiber composites.