Other Aliphatic Olefin Homopolymers

There are a number of occasions where a transparent plastics material which can be used at temperatures of up to 150°C is required and in spite of its relatively high cost, low impact strength and poor aging properties poly-(4-methylpent-l-ene) is often the answer. Like poly(vinyl chloride) and polypropylene, P4MP1 is useless without stabilisation and as with the other two materials it may be expected that continuous improvement in stabilising antioxidant systems can be expected. 

A number of polymers have been produced from higher olefins using catalysts of the Ziegler-Natta type. 

None of the polymers from unbranched olefins, other than ethylene, propylene or but-1-ene, has yet become important as a plastics material although some of them are of interest both as adhesives and release agents. One limitation of a 

274 Aliphatic Polyolefins other than Polyethylene, and Diene Rubbers 

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Instead of block copolymers, the use of pseudo-random linear copolymers of an aliphatic a-olefin and a vinyl aromatic monomer has been reported [20], where the styrene content of the polymer must be higher than 40 wt%. Preferred are styrene and ethylene copolymers. These blends may contain, amongst other things, an elastomeric olefinic impact modifier such as homopolymers and copolymers of a-olefins. Presumably the styrene-ethylene copolymer acts as a polymer emulsifier for the olefinic impact modifier. Using 5 wt% of an ethylene-styrene (30 70) copolymer and 20% of an ethylene-octene impact modifier in sPS, a tensile elongation (ASTM D638) of 25 % was obtained. 

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