Effect of solid paraffin on the integrity of welded interfaces and properties of ultra-high molecular weight polyethylene

Abstract

Ultra-high molecular weight polyethylene (UHMWPE) contains fusion defects, arising during the processing of the reactor powder. These defects have been implicated previously in failures of UHMWPE load-bearing surfaces, in knee and hip prostheses. To minimize the fusion defects of UHMWPE products, the low molecular weight solid paraffin (PW) was blended with UHMWPE. Our hypothesis was that the addition of PW could promote UHMWPE chain mobility and minimize the structural defects, thus improve the property of consolidated UHMWPE. The morphology and property of UHMWPE blends with PW were investigated by SEM, tensile test, DMA and stress relaxation. The addition of a small amounts of PW improved the surface flatness, bulk density and mechanical and wear properties of UHMWPE, presumably due to structural defect elimination through reducing entanglements and enhancing the chain mobility of UHMWPE.