Study Of Modification On Highly Anti-wear And Self-lubricated POM

M-UHMWPE and LLDPE was applied to improve friction and wear properties of polyoxymethylene (POM). Friction and wear properties of POM and its blends with M-UHMWPE and LLDPE were investigated. The enhanced mechanism of friction and wear properties of POM was explored by SEM, FT-IR, DSC, WAXD and AFM. The modified reference method of friction and wear properties of POM is supplied.Friction and wear properties of POM were significantly improved owning to the addition of modified-UHMWPE(M-UHMWPE) and linear low density polyethylene(LLDPE). The frictional coefficient and the wear rate of POM/M-UHMWP and POM/LLDPE/EAA are greatly decreased in the same conditions. The frictional coefficient of POM/M-UHMWPE(95/5) is reduce to 50% that of POM. The wear scar width of POM/M-UHMWPE blend is decreased from 5.00mm to 3.56mm.The frictional coefficient of POM/LLDPE/EAA(90/10/4) blend is reduced to 44% that of POM. Its wear scar width is decreased from 5.00mm to 3.88mm.The irregular transfer layer of POM is formed on the surface of the steel counterpart. With load increasing and wear time lengthening, the phenomenon of melting and soften occurred in the worn surface of POM. POM is transferred to the steel counterpart, a lot of loss of molten POM occurred, exhibiting the typical characterization of adhesion wear. The analysis of the worn surface of POMshows that temperature of the worn surface is high and the POM molecules are easily oriented, the melt temperature and crystallinity is improved. Under high sliding speed (400rpm), the melt loss is the major cause of POM wearing in short time due to the very high temperature at the worn surface.No transfer layer but the very thin and even lubricating film could be found in case the steel ring surface sliding with POM/M-UHMWPE(95/5) and POM/LLDPE/EAA(90/10/4) blends. The surface wear of POM blends does not show apparent increase with sliding time. In the course of friction and wear, the debris produced by M-UHMWPE and LLDPE transfer to the worn surface exits in the contact surface, which act as anti-friction and wear-resisting agent. With wear time lengthening, the lubricate layer is formed in the worn surface because of the melting of M-UHMWPE and LLDPE, which isolated the two contact surface effectively. The friction coefficient and wear rate of POM/M-UHMWPE and POM/LLDPE/EAA blends are thus reduced remarkably and anti-wear gets greatly improved.