The cold drawing of high polymers

摘要: Like many other polymers, amorphous polyethyleneterephthalate cold draws in the shoulders of a neck when stretched at room temperature. The draw ratio across is not constant for polymer, but found to depend on temperature and speed stretching, initial specimen cross-section birefringence. A local rise also observed shoulders. Isothermal load-extension curves have therefore been measured from 20 140°C, them an adiabatic curve has calculated. This negative slope range which appears be unstable. An alternative process extension tension shoulder, coupled with exchanges heat along by conduction, possible lower than that needed pure extension. For this second length it operates, it, can calculated simple are agree experimental data within factor two. theory then used discuss drawing some polymers.