Effects of Dopamine-modifed UHMWPE Powders on the Toughness and Tribological Properties of Epoxy Coating

Dopamine is used to modify the inert surface of ultra high molecular weight polyethylene (UHMWPE) powders for its oxidative self-polymerical property. The compatibility between powders and epoxy resin is enhanced and then epoxy coatings with excellent anti-wear and tough properties are prepared. Scanning electron microscope, X-ray photoelectron spectroscopy and infrared spectroscopy are utilized to characterize the surface morphology and the chemical states of the dopamine-modified powders. Tribological tester is utilized to evaluate the friction coefficient and wear rate of the epoxy coatings. Results show that a polydopamine layer which is full of polar groups adhered on the surface of dopamine-modified powders. This layer reacts with the epoxy resin and this enhances the compatibility. The ratios of O to C and N to C on the surface of dopamine-modified powders first increase with the modification time and then reach a maximum at a modification time of 5 h. The impact-resistance performance of epoxy coating is enhanced by increasing the dopamine-modified powder content from 6.7% to 20%. In addition, friction coefficient and wear rate are also decreased. The comprehensive performance of epoxy coating with dopamine-modified powders is better than the one with unmodified powders.