Influence of poly(ethylene glycol)-containing additives on the sliding wear of ultrahigh molecular weight polyethylene/polypropylene blend

The influence of poly(ethylene glycol) (PEG)-containing additives on the sliding wear of ultrahigh molecular weight polyethylene/polypropylene (UHMWPE/PP) blend was investigated in this paper. At low sliding speed (200 rpm, 30 kg, 30 min), the friction property and wear resistance of UHMWPE/PP blend can simultaneously be obviously improved by the addition of small amount of PEG (0–2 phr) or its hybrids (0–3 phr) with diatomite and glass bead. At high sliding speed (400 rpm, 10 kg, 30 min), the wear behavior of UHMWPE/PP blend can be improved by the addition of pure PEG only when PEG content was less than 1 phr and cannot be improved with the incorporation of hybrid additives under the tested conditions. The improvement in the friction and wear properties at low sliding speed with the addition of small amount of PEG-containing additives was durable and stable in a long period and the improving effect was influenced by sliding time less than by sliding speed. The analysis of the worn surfaces indicated that the adhesive wear was the predominant mechanism for the blends containing PEG and its hybrids at low sliding speed. The incorporated PEG can act as a lubricant in the interface, which retarded or suppressed the fatigue failure of the blends. UHMWPE/PP blends containing small amount of PEG-containing additives were superior to pure UHMWPE in wear behavior under the same condition, though their friction coefficient and wear scar width exceeded those of UHMWPE/PP matrix in some cases such as relatively more hybrid additives were incorporated or at high sliding speed.