高分子Polymer

按链的拓扑分为线型、支化、交联（网状）、星形和树枝状高分子。合成高分子是长度不一的分子混合物，必须用数均、重均分子量和分散度描述。分子链很长且能内旋转，产生大量构象，使高分子具有黏弹性、高弹性和玻璃化转变等小分子所没有的性质。高分子可以是非晶态或半结晶态，结晶度强烈影响强度、透明度和熔点。

By topology polymers are linear, branched, crosslinked (network), star or dendritic. Synthetic polymers are mixtures of chains of different lengths and are described by number- and weight-average molar mass and dispersity. Their long chains can rotate internally into enormous numbers of conformations, giving properties small molecules lack: viscoelasticity, rubber elasticity and the glass transition. Polymers may be amorphous or semicrystalline, and crystallinity strongly affects strength, clarity and melting point.

1833 年贝采利乌斯创造 polymer 一词，但指的是组成相同、分子量成倍数的物质。19 世纪末到 20 世纪初，主流观点认为橡胶、纤维素是小分子靠次价力形成的“胶体缔合物”。1920 年施陶丁格发表《论聚合》，提出这些物质是由共价键连接的长链大分子，经过激烈争论后被接受，他获 1953 年诺贝尔化学奖。1930 年代卡罗瑟斯合成尼龙和氯丁橡胶，为高分子学说提供了有力证明。

Berzelius coined the word polymer in 1833, but for substances with the same composition and multiple molar masses. Around 1900 the dominant view was that rubber and cellulose were colloidal associations of small molecules held by secondary forces. In 1920 Staudinger's paper 'On polymerisation' argued that they are long chains joined by covalent bonds; after fierce debate his macromolecular theory was accepted, and he received the 1953 Nobel Prize in Chemistry. Carothers's synthesis of nylon and neoprene in the 1930s gave strong support.

1950 年代齐格勒-纳塔催化剂实现立构规整聚合（1963 年诺贝尔奖）；弗洛里建立高分子溶液与统计理论（1974 年诺贝尔奖）；德热纳把软物质物理引入高分子研究（1991 年诺贝尔物理学奖）。全球塑料年产量已超过 4 亿吨，高分子材料广泛用于包装、建筑、交通、电子和医疗，同时塑料污染和回收利用成为重大环境议题。

In the 1950s Ziegler–Natta catalysts achieved stereoregular polymerisation (Nobel Prize 1963); Flory developed the statistical theory of polymer solutions (Nobel Prize 1974); de Gennes brought soft-matter physics to polymers (Nobel Prize in Physics 1991). World plastics output now exceeds 400 million tonnes a year and polymers pervade packaging, building, transport, electronics and medicine, while plastic pollution and recycling have become major environmental issues.