Abstract: Rubber-modified copolymers comprising 5 to 40 weight percent of an elastomer and 95 to 60 weight percent of a copolymer containing 1 to 50 mole percent of an imide derivative of an ethylenically unsaturated dicarboxylic acid monomer and 99 to 50 mole percent of one or more monomers copolymerizable therewith are prepared by the reaction of aqueous ammonia or amines with an aqueous suspension of a rubber-modified copolymer of the copolymerizable monomers and an ethylenically unsaturated dicarboxylic acid, anhydride, or half acid derivative. The reaction is carried out at a temperature between 125.degree. and 200.degree. C. at autogenous pressure for between 0.5 and 48 hours. The imide products can be recovered in the form of discrete particles, such as beads or pellets, if desired.

Abstract: Thermoplastic polymers containing a blowing agent are extruded into an unconfined zone and allowed to partially expand. The polymers are then conveyed through a confined moving passage of predetermined configuration formed, for example, by intermeshing cooled rolls, to shape the extrudate to the predetermined configuration and solidify the surface layers. The extrudate is further cooled by subjecting alternate surfaces to cooled roll surfaces, whereby a continuous ribbon, or shaped extrudate, having a dense skin and a foamed core is formed. The method is particularly applicable to small cross-section profiles which can be cut into short lengths to be useful as ice-cream sticks or tongue depressors.