MORPHOLOGY AND POROSITY OF POLY(VINYLBENZYL CHLORIDE) BEADS CONTAINING STYRENE-ETHYLENE, BUTYLENE-STYRENE TRIBLOCK COPOLYMER

Because crosslinked, porous poly(vinylbenzyl chloride) is an attractiv e substrate for sensors and actuators based on polymer swelling, its p roperties were studied as a function of formulation. Polymer beads wer e formed by suspension copolymerization of vinylbenzyl chloride and di vinylbenzene in the presence of xylene/dodecane and Kraton G1652, a st yrene-ethylene, butylene-styrene triblock copolymer. As polymerization proceeds, the dodecane phase separates forming aliphatic domains with in the aromatic polymer. After polymerization, the xylene/dodecane is removed to yield a porous material. These materials were examined by s canning electron microscopy and mercury porosimetry. It was found that including Kraton G1652 in the formulation leads to morphologies with greatly increased surface area compared with morphologies observed wit hout Kraton G1652. Formulations with 2% Kraton contained a large numbe r of small pores in a continuous aromatic polymer matrix. Formulations with 8 and 14% Kraton have a morphology consisting of small connected spheres surrounded by empty void space. (C) 1997 Elsevier Science S.A .