Polyethylene (low density)

/Polyethylene (low density)
Polyethylene (low density)2016-12-06T05:35:21+00:00


Carrier bags made from LDPE Ethylene compressor for first production of ICI Polythene
LDPE inkwell moulded by E Shipton 1940s Self-seal tops on LDPE bags Toy domestic ware in polyethylene

Polyethylene, was discovered largely by accident in 1933 by scientists working for ICI.

From 1937 pilot plant work proceeded but only a small amount of polymer was produced. The first plant came into operation in September 1939 and the resultant product, named "Polythene" by ICI, was to have a major impact on the war effort. It was found that the long chain, low density white polymer could be extruded as film and coated around wires and cables to give greatly enhanced performance. Polythene was a superb insulator with high dielectric and low loss factor and was thus in great demand for submarine cables, radar applications, etc.

Major production continued from 1942 and ICI licensed other companies thereafter in the production of high pressure polyethylene which produced the low density product – LDPE. However, the extreme conditions and costs for production coupled with low temperature softening, creep and stress cracking of LDPE limited the full potential of the polyethylene family of polymers in film blowing and injection moulding volume applications.

The development of new improved conditions for manufacture and control of molecular structures was to create accelerating and dramatic changes in the growth of polyethylene and other polyolefin polymers. (See Karl Ziegler and Giulio Natta) The subsequent huge range of products, especially in packaging films and containers coupled with great design and production flexibility through controlled material properties, has affected almost every aspect of modern life.