Determination of the optimum polymer concentration for ultrahigh molecular weight polyethylene gel films by zone drawing method

Abstract

A new method using a simple zone drawing technique was suggested for determining optimum initial concentration of polymer solution which has suitable macromolecular entanglements. Ultra high molecular weight (UHMW) polyethylene (PE) gel films were prepared from decalin solutions with concentrations of 0.3, 0.5, 0.7, and 1.0 g/dL, and different gelation/crystallization temperatures. In order to investigate drawing behaviors of UHMW PE gel films with different solution concentrations, those prepared were drawn under various zone drawing conditions. Through a series of experiments, it turned out that the initial concentration of PE solution in decalin caused significant changes in the draw ratio of UHMW PE gel film. That is, the one-step zone draw ratio of the gel film for initial concentration of 0.5 g/dL was at its maximum and gradually decreased at higher or lower concentrations. Moreover, this tendency was similar to the maximum draw ratio data. Thus, it was shown that the initial concentration of 0.5 g/dL is the optimum polymer concentration to produce maximum draw ratio in this work. Based on these results, it may be concluded that the optimum concentration of the initial UHMW PE solution can be determined directly by the zone draw ratio.