THE PRODUCTION OF ORIENTED DIE-DRAWN TUBES IN POLYPHENYLENE SULFIDE AND IN POLY 4-METHYL PENTENE-1 HOMOPOLYMER AND COPOLYMER

The die drawing process has been used to produce uniaxially and biaxia lly drawn tubes from three different polymers, polyphenylene sulphide (PPS), poly 4-methyl pentene-1, (P4MP) and poly 4-methyl pentene-1 cop olymerised with 1-decene (1%), (P4MPC). The die drawing process is des cribed and process improvements are discussed which would allow furthe r optimisation of drawn tube properties. In particular, machine modifi cations are suggested which would allow more nearly balanced machine a nd hoop draw ratios to be achieved. For some of the samples and tests the drawn tube dimensions and properties prevented standard mechanical test methods to be applied and modified tests suitable for samples cu t from biaxially drawn tubes are described. Comparisons were then made between the three polymers which show that biaxially drawn PPS tubes had substantially better yield stress, tear strength and impact resist ance than the P4MP polymer and copolymer tubes when drawn to similar d raw ratios. The PPS samples showed no tendency to fibrillate or delami nate.