阳离子聚合反应为一种链增长聚合反应，反应中阳离子引发剂(cationic initiator)会将电荷转移单体，使单体变得有反应性。而这个具反应性单体会与其他单体进行相似的反应，最后形成聚合物。. 阳离子聚合反应中的这种单体，必须受具有提供电子取代基(electron-donating substituent)的烯烃(olefins)和杂环(heterocycles)限制。相似于阴离子聚合反应，阳离子聚合反应对反应中所使用的溶剂(solvent)非常敏感，特别是溶剂可形成游离离子(free ions)的能力，此能力决定了增长的阳离子链的反应性。 阳离子聚合反应用于聚异丁烯(polyisobutylene)的产生(如：丁基橡胶用于轮胎的内胎)和聚N-乙烯基咔唑(N-vinylcarbazole，PVK)

Cationic polymerization is a type of chain growth polymerization in which a cationic initiator transfers charge to a monomer which then becomes reactive. This reactive monomer goes on to react similarly with other monomers to form a polymer. The types of monomers necessary for cationic polymerization are limited to olefins with electron-donating substituents and heterocycles. Similar to anionic polymerization reactions, cationic polymerization reactions are very sensitive to the type of solvent used. Specifically, the ability of a solvent to form free ions will dictate the reactivity of the propagating cationic chain. Cationic polymerization is used in the production of polyisobutylene (used in inner tubes) and poly(N-vinylcarbazole) (PVK).