聚碳酸酯Polycarbonate

主链中刚性的苯环和异丙叉基使玻璃化温度高达约 147 °C，非晶透明（透光率约 89%）。分子链在受冲击时可通过局部运动（次级松弛）吸收能量，因此冲击强度是 PMMA 的约 30 倍、玻璃的约 250 倍，可用于防弹玻璃。缺点是表面硬度低易划伤，耐碱和耐有机溶剂性较差，长期在应力下接触某些溶剂会应力开裂。

Rigid benzene rings and isopropylidene groups give a glass transition of about 147 °C, and the material is amorphous and clear (about 89% transmission). Under impact the chains absorb energy through local (secondary) relaxations, so its impact strength is about 30 times that of PMMA and 250 times that of glass, enough for bullet-resistant glazing. Drawbacks are low surface hardness and scratching, poor resistance to alkalis and some solvents, and stress cracking when stressed in contact with certain solvents.

1898 年艾因霍恩首次制得芳香族聚碳酸酯，但未得到实用。1953 年德国拜耳公司的施内尔和美国通用电气公司的福克斯几乎同时独立开发出双酚 A 型聚碳酸酯，分别以 Makrolon（1958 年）和 Lexan（1960 年）商标投产。传统界面缩聚法使用剧毒光气，2002 年起旭化成开发的以 CO₂ 为原料的非光气熔融酯交换法实现工业化。

Einhorn first made an aromatic polycarbonate in 1898, but it found no use. In 1953 Hermann Schnell at Bayer in Germany and Daniel Fox at General Electric in the United States independently developed bisphenol A polycarbonate, launched as Makrolon (1958) and Lexan (1960). The traditional interfacial process uses highly toxic phosgene; from 2002 Asahi Kasei's phosgene-free melt transesterification route, starting from CO₂, was commercialised.

聚碳酸酯用于光盘（CD、DVD）、眼镜片、头盔面罩、防弹玻璃、车灯罩、温室和体育馆采光板、电子产品外壳和医疗器械。由于残留或水解产生的双酚 A 有雌激素样作用，许多国家已禁止在婴儿奶瓶中使用聚碳酸酯。

Polycarbonate is used for CDs and DVDs, spectacle lenses, helmet visors, bullet-resistant glazing, headlamp lenses, greenhouse and stadium roofing, electronic housings and medical devices. Because residual or hydrolytically released bisphenol A has oestrogen-like activity, many countries ban polycarbonate in baby bottles.