Abstract: Polymer-inorganic hybrid foam, having utility as construction materials, comprised of a continuous plastic phase or backbone structure of unexpanded polymer, e.g. polyvinyl acetate, vinyl-acrylic copolymer or asphalt or bituminous pitch, having distributed therein particles of an inorganic phase such as Portland cement particles, such inorganic phase being substantially free of sand, rock or aggregate, the cells of the hybrid foam being highly uniform, such hybrid foam being strong, and load supporting, and of low density, and being fire resistant and thermally insulating.

Abstract: Pneumatic means comprising a hollow mandrel or hollow tube having secured around its outer surface along the length thereof according to one embodiment, a flexible open-cell polyurethane foam sleeve and an outer skin formed of a flexible non-permeable plastic such as a vinyl plastic skin adhesively secured to the outer surface of the flexible open-cell foam sleeve, and air passages for communication between the interior of the mandrel and the open-cell foam sleeve, the resulting assembly being positioned in a mold for production of cored structural panels. In operation the tool assembly is placed under pressure and expanded to force the plastic skin of the assembly outwardly during pouring and setting of the construction material, e.g., a cement or cement-polymer composition in a mold, and after setting thereof the tool assembly is subjected to reduced pressure or a vacuum to withdraw the plastic skin from the set composition, e.g.