Preparation and properties of polymers from aryl cyclic sulfonium zwitterions

Abstract

Abstract A new class of zwitterionic monomers were prepared in which the positive and negative sites are cyclic sulfonium and phenolate. Thermal polymerization occurs by phenolic anionic attack upon the aliphatic carbon α to the sulfonium sulfur. Polymerization proceeds with ring opening and net loss of charge to form nonionic polymers. The monomeric zwitterions are generally hydrated, crystalline solids that are soluble in water or alcohol. Chlorination of the aromatic portion of the molecule yields nonhydrated species. The polymerizations of 1‐(4‐hydroxy‐3‐methylphenyl)tetrahydrothiophenium hydroxide inner salt (dihydrate) and 1‐(3,5‐dichloro‐4‐hydroxyphenyl)tetrahydrothiophenium hydroxide inner salt were studied. The latter monomer gave a polymer with M̄ n of 46,000 when a nucleophile was present as an initiator. The physical properties of this polymer were determined. Cyclization appears to be the main mechanism of termination in the polymerization of zwitterions.