Isobutylene ( -methylpropene) does not undergo efficient polymerization via free-radical or anionic — Polymers Chemistry Question

💡 Solution & Explanation

Isobutylene has two electron-releasing ($-CH_3$) groups, which increase the electron density of the double bond (making it susceptible to electrophilic attack) and heavily stabilize the intermediate tertiary carbocation via hyperconjugation and inductive effects. Thus, it undergoes cationic chain polymerization.