Deformation of Polymers During Hydrostatic Extrusion

Abstract

Crystalline as well as amorphous polymers and a thermosetting resin were hydrostatically extruded with pressures up to 4 kilobars. A linear relation was obtained between the extrusion pressure and extrusion ratio. Temperature of the billets during the extrusion process was determined, along with the flow pattern of the deformation. Tension tests at the temperature, to which the billet was exposed during the extrusion, was carried out at atmospheric pressure on the high-density polyethylene specimen to supply a theoretical basis to the experimental formula. Effects of temperature and strain rate on the extrusion process are discussed in the light of the temperature-time superposition principle.