The active center of carbon cationic polymerization is usually carbon cation

and the initiator of carbon cationic polymerization must be the compound producing cationic active species

including proton source compounds such as carboxylic acid

alcohol and trace water

and carbon cation source compounds such as halohydrocarbon

carboxylic acid ester and ether. However

because of the outdated materials used

carboxylic acid

trace water

halogenated hydrocarbon and carboxylic acid ester etc. were mistakenly defined as secondary initiators in several versions of current "polymer chemistry" textbooks

while strong Lewis acids such as BF

3

were defined as the main initiators. According to the principle of ionic polymerization

proton source compounds and carbon cation source compounds are the true initiators

while strong Lewis acids are only activators

catalysts or co-initiators. Based on the long-term teaching experience

this paper tries to analyze the basic principle and initiation system of cationic polymerization from the chemical principle. It is hoped that the latest research results in this field can be incorporated into undergraduate teaching

so as to achieve "teaching alone with innovation" and to cultivate modern polymer young talents with solid professional theoretical foundation.