Abstract: A method of forming a high impact strength article of nylon/polyurea copolymer by reaction injection molding precursors of a polyurea prepolymer and a caprolactam together including the steps of prereacting a diisocyanate, a diamine and caprolactam to form a polyurea prepolymer having carbamyl caprolactam terminated end groups and then rapidly mixing the prepolymer with suitable amounts of caprolactam and a caprolactam alkali metal salt initiator and adding the mixture to a heated mold to polymerize the mixture and form the article.

Abstract: Poly(methyl methacrylate) is modified to have improved impact resistance by forming an ABA-type block copolymer where the A segments are poly(methyl methacrylate) and the B segment is polycarbonate. The ABA block copolymer is moldable, transparent and has a number average molecular weight (Mn) in the range of from about 15,000 to 100,000.

Abstract: According to our invention, thermoplastic poly(vinyl chloride) block copolymer resins of the (AB).sub.n type are formed which are flexible without the addition of an external plasticizer for poly(vinyl chloride). These novel block copolymer resins have average molecular weights (Mn) in the range of from about 15,000 to 60,000 and contain alternating rigid poly(vinyl chloride) segments and flexible linear aliphatic polyether or polyester segments, each having an average molecular weight in the range of from about 1,000 to 5,000. The resins of our invention have excellent physical properties which make them suitable substitutes for externally plasticized poly(vinyl chloride) homopolymers, particularly in automotive applications.

Abstract: Macroazonitrile molecules formed of flexible poly(ethylene oxide) segments connected by azo linkages are heated in the presence of vinyl chloride to initiate the addition polymerization of the monomer onto the ends of the poly(ethylene oxide) segments. An ABA type block copolymer is formed wherein the A parts are poly(vinyl chloride) segments and B is a poly(ethylene oxide) block which was originally part of the macroazonitrile. The flexible poly(ethylene oxide) segments of this block serve as an internal (intramolecular) plasticizer such that the copolymer may be used in applications typically filled by externally plasticized poly(vinyl chloride). External plasticizers are still required but their concentrations may be reduced to a level where plasticizer migration problems are eliminated.