Cationic copolymerization of indene with styrene derivatives: Synthesis of random copolymers of indene with high molecular weight

Abstract

Abstract Random copolymers with high molecular weights of indene and p ‐methylstyrene ( p MeSt) were synthesized by cationic polymerization with trichloroacetic acid/tin tetrachloride in CH 2 Cl 2 at low temperatures. When indene and p MeSt (1:1 v/v), for example, were polymerized at −40 °C, both monomers were consumed at very similar rates to give a copolymer with high molecular weight [number‐average molecular weight ( M n ): 8–9 × 10 4 ]. This is indeed quite unexpected behavior for the combination of these two monomers because p MeSt polymerized over 1000 times faster than indene in the homopolymerization under the reaction conditions previously described. The product copolymer of indene and p MeSt had a random monomer sequence in it that was confirmed by NMR analyses and thermal‐property measurements. In sharp contrast with p MeSt, styrene and p ‐chlorostyrene, which have no electron‐donating groups on the phenyl ring, led to low molecular weight polymers ( M n < 10,000) in the copolymerization with indene (1:1 v/v). © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2449–2457, 2002