THERMOMECHANICAL STUDY OF HIGH-DENSITY POLYETHYLENE AFTER PLASTIC DEFORMATION UNDER HIGH PRESSURE

The thermomechanical properties of high-density polyethylene samples (Тmlt = 142°С) subjected to plastic deformation under a pressure of 0.5–1.0–2.0 GPa at room temperature have been investigated on an anvil-type high-pressure apparatus. The decrease in the thickness of deformed samples upon heating depends on the processing pressure and the state of the compressive anvils, namely, grounded or insulated. UV irradiation and storage of the samples at room temperature reduced the effect caused by deformation. The established effects have been associated with a significant influence of charges trapped by structural defects formed during plastic deformation of the polymer on the thermomechanical properties of deformed samples.