Polymerization of α‐methyleneindane: A cyclic analog of α‐methylstyrene

α‐Methyleniedane (MI), a cyclic analog of α‐methylstyrene which does not undergo radical homopolymerization under standard conditions, was synthesized and subjected to radical, cationic, and anionic polymerizations. MI undergoes radical polymerization with α,α′‐azobis(isobutyronitrile) in contrast to α‐methylstyrene, owing to its reduced steric hindrance, though the polymerization is slow even in bulk. Cationic and anionic polymerization of MI with BF3OEt2 and n‐butyllithium, respectively, proceed rapidly. The thermal degradation behavior of the polymer depends on the polymerization conditions. The anionic and radical polymers are heteortactic‐rich. Reactivity ratios in bulk radical copolymerization on MI (M2) with methacrylate (MMA, M1) were determined at 60°C (r1 = 0.129 and r2 = 1.07). In order to clarify the copolymerization mechanism, radical copolymerization of MI with MMA was investigated in bulk at temperatures ranging from 50 to 80°C. The Mayo–Lewis equation has been found to be inadequate to describe the result due to depolymerization of MI sequences above 70°C. Copyright © 1991 John Wiley & Sons, Inc.