Abstract: Impact polystyrene resin compositions and articles fabricated from them are prepared from styrene and a polybutadiene rubber having a vinyl isomer content of 11 to 22 percent.

Abstract: An otherwise conventional two-stage (mass suspension polymerization system for making impact polystyrene is modified in several respects: (a) the rubber (about 7% to about 10% of the polymerization charge) to be dissolved in styrene has a cis content greater than 97%, (b) a portion, i.e. 5-15%, of the free-radical catalyst to be used is added at the beginning of the mass polymerization stage, i.e. at about 235.degree.-250.degree. F. after dissolving the rubber in the styrene, and (c) the addition of the major portion (about at least 85%) of the mercaptan chain regulator added is made at the time of the initiation of the mass polymerization stage when the temperature first reaches the temperature employed for mass polymerization (such temperature selected from the range of 235.degree.-250.degree. F.). The rubber used should have a viscosity as a 5% solution in toluene of 70-95 cps at 25.degree. C.

Abstract: A process is described for preparing high impact polystyrenes by mass-suspension polymerization of styrene and a polybutadiene rubber having a vinyl isomer content of 11 to 22 percent. The high impact polystyrenes made by the disclosed process are useful for forming extruded sheet with balanced impact properties suited for deep draw thermoforming.

Abstract: Alkali metal salts of copolymers of ethylene and acrylic and/or methacrylic acid are provided. The alkali metal salts are prepared by saponifying copolymers of ethylene and an alkyl acrylate or an alkyl methacrylate in the presence of an aqueous solution of an alkali metal hydroxide.