加成聚合

加成聚合，或称加聚（Polyaddition，addition polymerisation）^[2][3]是一种通过独立的加成反应形成聚合物的聚合反应。加成聚合发生在低聚合度的分子之间，这些分子具有不同的功能团，如二聚体、三聚体和低聚物，它们通过反应形成更高分子量的物质。与链式聚合不同，加成聚合通常只有在几乎完全转化后才会形成聚合物，这一点与缩聚反应相似。^[4]

IUPAC definition

Polyaddition

A polymerization in which the growth of polymer chains proceeds by addition reactions between molecules of all degrees of polymerization. Notes: 1. The growth steps are expressed by:

   Px+Py → Px+y {x}∈{1,2,…∞};{y}∈{1,2,…∞}

where P_x and P_y denote chains of degrees of polymerization x and y, respectively.

2. The earlier term 'addition polymerization' embraced both the current concepts of 'polyaddition' and 'chain polymerization', but did not include 'condensative chain polymerization'.^[1]

典型的加成聚合反应是合成聚氨酯。