Cationic polymerization of bis(1‐alkylvinyl)benzenes and related monomers, 1. Structure elucidation of 1,1,3‐trimethyl substituted polyindane

Abstract 1,4‐Bis(1‐chloro‐1‐methylethyl)benzene (BINIFER)/borontrichloride is known to be a very efficient initiating system for cationic polymerization of e.g. isobutene at low temperature (< −60°C). However, at higher temperature this system polymerizes by its own. The obtained polymers show a remarkable, high thermal stability and are soluble in common solvents. The analytical results indicate a very uniform structure consisting exclusively of 1,1,3‐trimethyl indane‐3,5‐diyl units. Other possible structures could be excluded. A mechanism explaining the surprisingly selective polyindane formation is discussed.