Room temperature, simple and efficient synthesis and functionalization of aromatic poly(arylene sulfide)s, poly(arylene sulfoxide)s and poly(arylene sulfone)s

Abstract

Aromatic polysulfides and polysulfones are a large group of sulfur-containing polymers representing an important class of materials with diverse applications, ranging from high performance engineering plastics, gas separation, ultrafiltration, nanofiltration, ion-exchange membranes, and materials for biomedical applications. All these polymers are produced by high temperature nucleophilic substitution reactions of dichlorobenzene with sodium sulfide (PPS) and dichlorodiphenyl sulfone with bis-phenols in the presence of basic catalysts (PAES). In the present work, novel poly(arylene sulfide)s were obtained in nearly quantitative yields, by one-pot, room temperature, metal-free, highly regioselective, non-stoichiometric step-polymerizations of diphenyl sulfide (DPS) with 1,1,1-trifluoroacetone and isatin, in a mixture of trifluoromethanesulfonic acid (TFSA) with CH2Cl2. The polymers obtained were soluble in common solvents. The oxidation of the poly(arylene sulfide)s with H2O2 at room temperature afforded poly(arylene sulfoxide)s and poly(arylene sulfones) with high oxidation selectivity. On heating, sulfoxide groups of the poly(arylene sulfoxide)s are converted into sulfide groups and oxygen, which acts as an expanding agent, is released in the process to form nanofoams with homogeneous pore distribution. Controlled incorporation of hydroxymethyl-, carboxy-, and “click” able allyl- and propargyl- functionalities is carried out by room temperature, post-modification reactions of the polymers bearing reactive oxindole groups.