| 摘要 |
A normally solid thermoplastic vinyl aromatic polymer has intimately incorporated throughout 0.01-2% of saturated aliphatic monocarboxylic acid which comprises at least 75% of one or more acids containing 22-25 carbon atoms. The polymer may be polystyrene or a copolymer of 70-80% styrene and 30-20% acrylonitrile. The acid may be behenic, tricosanoic, tetracosanoic or pentacosanoic and may contain not more than 25% of a C18- 20 acid, e.g. a commercial behenic acid which contains 80% of C22, 12% C20 and 8% C17 or C18 aliphatic monocarboxylic acids. The composition may be produced by polymerizing styrene in the presence of behenic acid using specified time/temperature conditions or by heat plastifying the polymer in admixture with the molten acid. In a comparative example stearic acid was used in place of behenic acid. The composition may be formed into articles, e.g. bottle caps or film. |
