Non-isothermal crystallization of UHMWPE

Processing of Ultra High Molecular Weight Polyethylene (UHMWPE) parts invol ves non-isothermal cooling leading to crystallinity variations, which cause variations in the mechanical properties. Study of non-isothermal crystalli zation kinetics of UHMWPE forms the basis for process modelling. The crysta llization of UHMWPE was studied at seven different cooling rates. The cryst allization onset and peak temperatures were linearly related to the cooling rate. The crystallization of UHMWPE was concluded to be a nucleation domin ated process with small contribution from growth of nuclei. Differences in ultimate crystallinity (similar to 11%) were produced due to different cool ing rates. A significant portion of the change in ultimate crystallinity oc curred at lower cooling rates (< 6 degrees C min(-1)). At higher cooling ra tes (6-22 degrees C min(-)1) the change in ultimate crystallinity was insig nificant.