Sulfonium polymers derived from Ar‐vinylbenzyl chloride. I. Exploratory study of the preparation and properties of the monomers and polymers

Although sulfonium salts are well known, polymeric sulfonium salts seldom have been mentioned in the chemical literature. This paper describes exploratory work in the preparation of various sulfonium monomers and polymers from ar‐vinylbenzyl chlorides ( ortho and para isomers). These chlorides—particularly the para isomer—reacted readily with 2,2′‐thiodiethanol and water to yield the corresponding ar‐vinylbenzyl sulfonium chloride monomers in aqueous solution.The odorless, reactive monomer mixture polymerized readily with persulfate or hydroperoxide catalysts; however, polymerization could be inhibited with cupric salts. Copolymerization with trimethyl(ar‐vinylbenzyl)ammonium chloride was random. In copolymerization with acrylamide or acrylonitrile, the sulfonium monomer was more reactive. Analogous sulfonium monomers were made by reaction of ar‐vinylbenzyl chlorides with various sulfides. In general, all the sulfonium monomers yielded homopolymers which were fairly stable in aqueous solution in the absence of strongly nucleophilic agents which would attack the sulfonium groups. However, when dried at room temperature the polymers would crosslink; and when heated, the polymers became hydrophobic also. Scrambling of the sulfonium group substituents during drying, and nucleophilic displacement reactions by chloride ion during heating were likely explanations. The high cationic charge on the polymers made them substantive to cellulose fibers. This property, when coupled with high nucleophilic reactivity of the sulfonium groups with the carboxylate sites of the pulp or other anionic counterious during drying and heating, made the polymers very effective as beater additives for imparting wet strength to paper.