Surface modification of UHMWPE fibers by means of polyethylene wax grafted maleic anhydride treatment

A novel surface modification method for ultrahigh molecular weight polyethylene (UHMWPE) fibers to improve the adhesion with epoxy matrix was demonstrated. Polyethylene wax grafted maleic anhydride (PEW-g-MAH) was deposited on the UHMWPE fibers surface by coating method. The changes of surface chemical composition, crystalline structure, mechanical properties of fiber and composite, wettability, surface topography of fibers and adhesion between fiber and epoxy resin before and after finishing were studied, respectively. The Fourier transform infrared spectroscopy spectra proved that some polar groups (MAH) were introduced onto the fiber surface after finishing. The X-ray diffraction spectra indicated that crystallinity of the fiber was the same before and after finishing. Tensile testing results showed that mechanical properties of the fiber did not change significantly and the tensile strength of 9 wt % PEW-g-MAH treated fiber reinforced composite showed about 10.75% enhancement. The water contact angle of the fibers decreased after finishing. A single-fiber pull out test was applied to evaluate the adhesion of UHMWPE fibers with the epoxy matrix. After treatment with 9 wt % PEW-g-MAH, a pull-out force of 1.304 MPa which is 53.59% higher than that of pristine UNMWPE fibers was achieved. (C) 2018 Wiley Periodicals, Inc.