Synthesis of carboxy-terminated telechelic oligostyrenes by Dead End Polymerization

Styrene was polymerized with 4,4'-azobiscyanovaleric acid (ACVA) in order to obtain carboxy-telechelic polystyrene (CTPS) using the Dead-End Polymerization (DEP) conditions. First, we focused on experimental conditions leading to oligomers with molecular weights about 2000 g mol(-1). Second, we demonstrated by-products of ACVA radicals are also synthesized in the DEP conditions by combination or by disproportionation. The purification of CTPS was investigated in order to extract the by-products of ACVA. An extraction of these by-products in H2O pH 7 is suggested. Finally, the acid functionality of oligostyrene is evaluated by H-1 NMR and conductimetric titrations. A functionality about 2 is obtained that confirmed the synthesis of CTPS. Copyright (C) 2002 Society of Chemical Industry.