Surface modification of UHMWPE fibers with chlorination and polydopamine for enhancing the mechanical properties of composites

Ultra-high molecular weight polyethylene (UHMWPE) fibers had many excellent mechanical properties, but their applications in composites were limited due to the weak interfacial adhesion between UHMWPE fibers with non-polar methylene and resin matrix. This paper explored an efficient method for the damage-free modification of fibers by chloride grafting followed by polydopamine (PDA) deposition to obtain UHMWPE-Cl-PDA fiber while maintaining the excellent mechanical properties of the fiber. The chemical components of surface treated fibers were observed by XPS and FTIR-ATR, and the results proved that the fiber surface has been successfully chlorinated and then coated with PDA layer. The surface morphologies of fibers measured by SEM showed the rough surface of UHMWPE-Cl-PDA fibers was beneficed to anchor the resin matrix. The different mechanical properties of composites were studied, such as interfacial shear strength (IFSS), impact strength, flexural strength and modulus, especially the IFSS between UHMWPE-Cl-PDA and epoxy matrix and the impact strength of UHMWPE-Cl-PDA composite were increased by 29.1% and 53.8%, respectively, compared with UHMWPE fibers deposited by PDA.