INCORPORATION OF BENZOCYCLOBUTENE INTO POLYSTYRENE ALLOWING POSTPOLYMERIZER CHAIN EXTENSION BRANCHING

The introduction of long-chain branching in polystyrene has the potent ial to improve some of the properties of the polymer. However, our att empts to make branched polystyrene in continuous free-radical bulk sty rene polymerization processes has led to gel formation and eventual re actor fouling. This paper describes a new approach for introducing lon g-chain branching into polystyrene which would eliminate the reactor f ouling problem. The approach is to place latent functionality on the p olymer during polymerization which subsequently reacts to form branche s upon thermolysis at temperatures > 200-degrees-C. This study focuses on the benzocyclobutene (BCB) moiety as the latent functionality. BCB is incorporated into the polymer chain by initiation with BCB functio nal peroxides, resulting in chain extension/branching upon heating at 240-degrees-C.