Solubilization of poly(phenylene sulfilde) via sulfonium formation by alkylation

Poly(phenylene sulfide) was solubilized to poly(arylenesulfonium) salts 5 by the acidified reaction with aliphatic esters (methyl formate, methyl triflate, ethyl formate, and ethyl acetate). The reaction quantitatively proceeds in sulfuric acid or triflic acid to give the corresponding alkylated polymers, which were well-characterized by various spectroscopic methods. The effects of the acidity, the esters, and the reaction temperatures on the alkylation were investigated. Polymers 5 are soluble in acids and polar organic solvents depending upon the alkyl substituents and counteranions. Poly(phenylene sulfide) could be regenerated by the dealkylation of 5 with refluxing pyridine without structural changes and decomposition.