Abstract: Laminated skin-foamed core sandwich structures characterized by an excellent stiffness and load-bearing capability to weight ratio are prepared by heating in a closed mold a sandwich construction that comprises skin layers that comprise a thermoplastic polymer having a glass transition temperature in the range of 75.degree. to 85.degree. C. and reinforcing fibers and a core that comprises a thermoplastic polymer that is compatible with the polymer in the skin layers and that has a glass transition temperature that is 10.degree. to 20.degree. C. lower than that of the polymer in the skin layers and a blowing agent at a temperature sufficient to fuse and expand the core and to fuse the skin layers and bond them to the expanded core.

Abstract: The polymerization of a monomer component that comprises vinyl chloride in an aqueous medium in the presence of a free radical generating polymerization initiator is terminated by introducing into the polymerization reaction mixture when from 70% to 95% of the monomer component has been polymerized from 0.01% to 0.10% by weight, based on the weight of the monomer component, of a chain-terminating agent that is an alkyl-substituted trisphenol, such as 1,1,3-tris(2-methyl-4-hydroxy-5-tert.butylphenyl)butane.