PROCESSING AND MORPHOLOGY OF HYPERBRANCHED POLYESTER POLYOL / POLYSTYRENE BLENDS

摘要

Recent work has shown that hyperbranched polymers have promise for use as processing aids for polyolefins and as toughening agents for thermosetting resins. This promise stems from the high reactivity and unique rheological properties of hyperbranched polymers, which are attributable for the unusual molecular structure. However, there are difficulties associated with the blending of these small, branched molecules into high molecular weight polymers, and processing can be challenging. In this study, we investigate the blending of hyperbranched polyester polyols (HBP) and high molecular weight polystyrene using batch and continuous processing techniques. The overall size, or generation, of the individual hyperbranched polyols is varied, as is the reactivity of the thermoplastic matrix toward to the polyol. Large reductions in system viscosity resulted from the addition of the hyperbranched polymers to the polystyrene. High energy processing and reactive compatibilization were effective in producing finely dispersed morphology in the blends. The processing characteristics, compatibility, and morphology of the blends are reported as a function of HBP generation, reactivity, type of processing, and shear rate.