HIGH MOLECULAR WEIGHT POLYETHYLENE.

High molecular weight polyethylene is a term which encompasses a broad spectrum of polyethylenes in the 300,000 - 1,000,000 plus molecular weight range. Properties which are determined by the molecular weight, increasing as the molecular weight is increased, are the ultimate tensile strength; elongation at break; resistance to stress cracking; and notched Izod impact strength, particularly at low temperatures. Crystallinity is the most important factor in processing and applications of PE under consideration. The main processing technique for high molecular weight polyethylenes which can be moulded by conventional thermoplastics processing techniques is extrusion blow moulding. Major applicational outlet is for large containers which demand the increased toughness, stress cracking resistance and improved fatigue properties imparted by the higher molecular weight.