Abstract: Normally solid copolymers that are the result of addition polymerization of methyl methacrylate and indene, containing the monomers combined in the polymer structure in the following weight percentages:______________________________________ Weight Percent ______________________________________ Methyl methacrylate 46-95 Indene 54-5.

Abstract: Low viscosity, random tetrapolymers that are the result of addition polymerization of the monomers acrylonitrile, methyl methacrylate, .alpha.-methylstyrene and/or styrene, and indene, containing the monomers combined in the polymer structure in the following weight percentages:______________________________________ Weight Percent ______________________________________ Acrylonitrile 10-40 Methyl methacrylate 5-50 Indene 3-50 .alpha.-methylstyrene or 5-50 styrene or a mixture of both ______________________________________wherein said tetrapolymers have an inherent viscosity in the range from 0.08 to 0.4 deciliters per gram of polymer solution.

Abstract: The impact resistance of rigid polymeric resins (e.g. PVC, SAN, PMMA, etc.,) is enhanced by the incorporation therein of an improved toughener. This toughener comprises three distinct phases: (a) a core of thermoplastic or thermoset resin having a Tg below room temperature, (b) a rubber-like layer overpolymerized on the core, and (c) a relatively hard polymer layer overpolymerized on the rubber layer. The utilization of a "soft" core, or seed, apparently enhances the efficiency of the toughener in the rigid polymer. In one of the preferred embodiments of this invention, the improved toughener comprises a seed derived from a partially corss-linked poly(n-butylacrylate), a rubber-like (or intermediate) layer derived from a monomer mixture containing n-butylacrylate and an addition monomer and an outer layer (or shell) derived from a monomer mixture containing styrene and methylmethacrylate.