General Description : A linear isotactic polyolefin more properly called poly 4-methyl pentene-1 which is made by Ziegler-Natta type catalysis (see also General Information under Polyethylene - Low Density). Commercially available grades are copolymers. It is semi-crystalline, transparent and usually colourless (one common grade is slightly yellow), very light and - for a polyolefin - expensive. [Its density of 0.83g.cm ³ is very close to the theoretical minimum for thermoplastics]. Its properties are reasonably similar to those of other polyolefins, compared to which it is more brittle and more gas permeable. It has a higher melting point (240C) than most polyolefins and retains form stability up to temperatures close to this i.e. it softens more slowly with increasing temperature than is normal for thermoplastics. It has good release characteristics and good high frequency electrical and valuable acoustic/ultrasonic properties.

Applications include medical and laboratory apparatus, microwave components and cookware and electronic components.