CAPILLARY FLOW PROPERTIES OF FRACTIONATED POLYCHLOROPRENE

The effect of molecular weight of fractionated polychloroprene on its capillary flow properties was investigated by the use of a Koka type flow tester. The following relations were obtained among the molecular weight and other quantities: logP∝logMw, logγc∝-logMw, where P is the applied pressure, γc the critical shear rate, and Mw the weight average molecular weight. Moreover, it was proved that the die swell (D/D0) and the critical die swell (D/D0)c above whose shear rate a distortion occurred increased with an increase in Mw. At a certain shear rate, the critical molecular weight below which the die swell would not occur was defined.