Abstract: An anhydride-containing thermoplastic resin such as a styrene maleic anhydride copolymer is processed in a vented extruder in the present of a nitrogenous chemical blowing agent to both imidize at least a portion of the anhydride groups and remove volatile residues such as unreacted styrene monomer from the resin.

Abstract: A thermoplastic resin such as a styrene/maleic anhydride copolymer is treated to remove volatile impurities such as unreacted styrene by admixing with a chemical blowing agent and extruding under a vacuum. The chemical blowing agent is converted into an inert gas such as carbon dioxide during extrusion; the gas evolved is removed, together with the volatile impurities, through one or more vents in the extruder. The use of a chemical blowing agent, rather than the inert gas itself, permits the facile distribution of the CO.sub.2 stripping agent throughout the molten thermoplastic resin using commonly available extruders without the need for elaborate gas injection means.

Abstract: Resin blends having improved toughness and resistance to heat deformation are obtained by blending crystalline propylene polymers, random thermoplastic styrenic copolymers containing .alpha.,.beta.-unsaturated dicarboxylic acid anhydride, and amino- or hydroxy-functionalized elastomers. The amino- or hydroxy-functionalized elastomers may be formed in situ by the reaction of anhydride-functionalized elastomers and linking compounds having at least two active-hydrogen containing functional groups such as amino or hydroxyl.

Abstract: A polyblend composition containing an olefin polymer, a rubber-modified styrenic resin, and a block copolymer compatibilizer is disclosed. In a preferred embodiment, a crystalline propylene polymer, a styrene/maleic anhydride random thermoplastic copolymer modified with a grafted styrene/butadiene rubber, and a hydrogenated styrene/butadiene block copolymer are intimately mixed to form a useful thermoplastic polyblend.

Abstract: Thermoplastic resin compositions having good toughness and resistance to heat deformation are obtained by blending crystalline propylene polymers, elastomeric olefin polymers, random styrenic copolymers, and epoxy group-containing copolymers. For example, the composition may be a blend of polypropylene, ethylene-propylene or ethylene-propylene-diene monomer rubber, styrene/maleic anhydride copolymer, and ethylene/glycidyl methacrylate or ethylene/glycidol methacrylate/vinyl acetate copolymer. Physical properties are enhanced by the use of a two step blending procedure.

Abstract: Thermoplastic copolymers having excellent tensile and heat resistance properties are obtained by copolymerization of a monovinyl aromatic monomer, an .alpha.,.beta.-unsaturated dicarboxylic acid anhydride, an .alpha., .beta.-unsaturated carboxylic acid, and a C.sub.1 -C.sub.4 alkyl ester of methacrylic acid. In a preferred embodiment, a styrene/maleic anhydride/methacrylic acid/methyl methacrylate random copolymer is prepared. Impact properties are improved by incorporation of an elastomer.