聚苯乙烯Polystyrene

工业聚苯乙烯为无规立构，因庞大的苯环阻碍链段运动且无法结晶，玻璃化温度约 100 °C，室温下呈坚硬透明的玻璃态，折射率 1.59，透光率约 90%。苯环使其易溶于芳烃、氯代烃和酮类，耐油性差。间规聚苯乙烯（茂金属催化，1985 年）可结晶，熔点约 270 °C，是工程塑料。

Commercial polystyrene is atactic; its bulky phenyl rings hinder segmental motion and prevent crystallisation, so its glass transition is about 100 °C and it is a hard, clear glass at room temperature, with a refractive index of 1.59 and about 90% light transmission. The rings make it soluble in aromatics, chlorinated solvents and ketones and poorly resistant to oils. Syndiotactic polystyrene, made with metallocenes from 1985, crystallises and melts near 270 °C, an engineering plastic.

1839 年德国药剂师西蒙从苏合香树脂中蒸馏出苯乙烯，发现它放置后变成胶状物，误以为是氧化产物。1845 年霍夫曼和布莱斯证明这是不含氧的聚合产物，称为“间苯乙烯”。施陶丁格在 1920 年代以聚苯乙烯为模型研究高分子。1931 年德国巴斯夫开始工业化生产，1954 年陶氏推出发泡聚苯乙烯 Styrofoam。

In 1839 the German apothecary Eduard Simon distilled styrene from storax resin and found it turned jelly-like on standing, thinking it oxidised. In 1845 Hofmann and Blyth showed it was an oxygen-free polymerisation product, 'metastyrol'. Staudinger used polystyrene as a model polymer in the 1920s. BASF began industrial production in 1931, and Dow launched Styrofoam expanded polystyrene in 1954.

通用 PS 用于一次性餐具、CD 盒、实验室培养皿；HIPS 用于家电外壳和玩具；EPS 和 XPS 用于包装缓冲和建筑保温。发泡聚苯乙烯体积大、难回收，是海洋漂浮垃圾的重要来源，许多地区已禁止 PS 泡沫餐盒。聚苯乙烯可热解回收苯乙烯单体，近年来发现黄粉虫肠道微生物能降解它。

General-purpose PS goes into disposable cutlery, CD cases and Petri dishes; HIPS into appliance housings and toys; EPS and XPS into protective packaging and building insulation. Bulky, hard-to-recycle foamed PS is a major source of floating marine litter, and many places have banned PS foam food containers. Polystyrene can be pyrolysed back to styrene, and gut microbes of mealworms have recently been found to degrade it.