Abstract: Low density rigid foamed polyphosphazene articles having excellent physical and flammability properties are made by masticating a mixture of high molecular weight linear polyphosphazene, a curing agent (e.g., sulfur), an accelerator, a blowing agent and optionally fillers, processing aids and the like to form a substantially homogeneous blend and then stopping the masticating, heating to pre-cure and then heating to activate the blowing agent and complete the cure thereby forming a flexible foamed polyphosphazene composite, forming the flexible foamed polyphosphazene composition into a shaped composition, and thereafter heating the flexible foamed shaped polyphosphazene composition at a temperature and for a length of time which causes the flexible foamed polyphosphazene composition to become a rigid foamed polyphosphazene composition of the same shape as the flexible foamed polyphosphazene composition.

Abstract: A fire resistant thermal and acoustic composite insulating panel comprising at least one polyimide foam insert having a polyorganophosphazene septum adhered to at least one surface. The polyorganophosphazene is filled with about 50-500 parts, preferably 100-500 parts by weight of a heavy metal compound per 100 parts of polyorganophosphazene.

Abstract: This invention relates to a quick drying and setting coal binding system which comprises (a) an aqueous solution of SiO.sub.2 /Na.sub.2 O or SiO.sub.2 /K.sub.2 O; (b) a water soluble surfactant; and (c) an organic ester.

Abstract: Foamed polyphosphazene articles having consistent appearance and physical properties are made by masticating a mixture of high molecular weight linear polyphosphazene, a curing agent (e.g., sulfur), an accelerator, a blowing agent and optionally fillers, processing aids and the like until the temperature of the composition rises to a pre-determined level. Mixing is stopped and the composition is shaped, heated to pre-cure and then heated to activate the blowing agent and complete the cure.

Abstract: Process for compounding polyphosphazene gum by (a) mixing a composition comprising a curable polyphosphazene gum, filler, plasticizer and other conventional components but without any curing agent to form a non-curing masterbatch, (b) mixing a composition comprising a polyphosphazene gum and an excess amount of curing agent, at least 10 times that required to cure the phosphazene gum in this mixture and optionally containing other conventional components to form a concentrate and (c) blending the non-curing masterbatch from (a) with sufficient concentrate from (b) to provide an amount of curing agent sufficient to cure the entire resultant mixture.

Abstract: A thermoplastic molding composition having good gloss and physical properties is disclosed. This composition contains in intimate admixture: a vinyl chloride polymer; a copolymer of a vinyl aromatic compound and an .alpha.,.beta.-unsaturated cyclic anhydride; a styrene-maleic anhydride copolymer having a number average molecular weight within the range of from about 1000 to about 8000; and an alkyl diphenyl phosphite. The copolymer of a vinyl aromatic compound and an .alpha.,.beta.-unsaturated cyclic anhydride can be rubber modified.