ABSTRACT
Synthetic polymers that are brittle at or below room temperature need additives to expand their toughness over a broad temperature range. As graft rubber technology developed, it became apparent that, in addition to grafted particles, a fraction of much larger rubber particles was needed. R. Czerwinski patented a method for blending acrylo-nitrile-styrene-butadiene solvent-soluble graft copolymers and epoxy resins in a solvent or mixing these primary components without solvent on a rubber mill. T. Grabowski at Borg-Warner patented compositions of an emulsion acrylonitrile-butadiene-styrene (ABS) polymer, produced by grafting styrene and acrylonitrile onto a polybutadiene latex core, and blends with polycarbonates. Methyl methacrylate grafted rubber concentrates have been found to be useful for modifying polystyrene, high-impact polystyrene (HIPS), and incompatible blends of ABS and HIPS. P. Yang and D. Pickelman found that polytriazines based on cyanate ester resins exhibit improved toughness without sacrificing heat resistance when prepared by curing in presence of graft rubber concentrate particles grafted with a resin-soluble shell polymer.
