多巴胺改性UHMWPE粉末对环氧涂层韧性及摩擦性能的影响

利用多巴胺氧化自聚合性质改性超高分子量聚乙烯(UHMWPE)粉末惰性表面,制备得到改性粉末,并添加于环氧树脂中制备成耐磨环氧涂层,同时与添加未改性UHMWPE粉末的环氧涂层对比.采用扫描电镜(SEM)、X射线光电子能谱(XPS)和红外光谱(IR)表征改性粉末表面形貌和化学元素状态,利用摩擦磨损试验机测试环氧涂层表面的摩擦系数和磨损率.结果表明:改性粉末表面黏附1层含极性基团的聚多巴胺,能够与环氧树脂发生反应而固化在涂层中,相容性增强.改性粉末表面O,C元素相对含量比较O/C和N/C值随改性时间延长而增大,在5 h时趋于稳定.当改性粉末添加量从6.7%增至20%时,环氧涂层的抗冲击性能增强,摩擦系数和磨损率随之降低,改善了涂层的摩擦学性能,而且效果优于添加未改性粉末的涂层.

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.