Abstract: The present invention relates to a process for expanding thermoplastic polymer compositions, notably those containing polymers having processing temperatures in excess of 200.degree. C. and/or containing an ingredient which is susceptible to ammonia, characterized in that as the blowing agent certain carbonates (notably zinc carbonate) are used. Preferably a nucleating agent and a weak acid are present to aid cell formation.The invention also includes expandable polymer compositions and blowing agent formulations containing the carbonates.

Abstract: Unsaturated polyester resins having an acidity number of 5-90 mg. KOH/g. a molecular weight of 500-5000 and which are capable of entrapping air or other inert gases so as to form structural foams and which contain in the chain 0.1 to 20 mol% of amide to the minimum acceptable link section size. Acceptable chain links are therefore excluded from fitting into the opening whereas worn chain links which have been worn to a degree which equals or exceeds the limit of permissible wear slide into the opening thereby indicating that the chain should be removed from service.

Abstract: A black sorbent thermoset foam which has been prepared by the pyrolysis of a composition comprising at least one aromatic nitrogen-containing compound having the general formula:X -- Ar -- Yin which Ar represents an aromatic nucleus on which X and Y are substituents directly attached to the nucleus, X represents a substituent having a negative Hammett sigma constant and attached to the aromatic nucleus by a nitrogen, oxygen or sulphur atom, and Y represents a substituent having a positive Hammett sigma constant and attached to the aromatic nucleus by a nitrogen atom, the substituents X and/or Y optionally forming part of a ring fused onto the aromatic nucleus, in an effective sorbtive substance for polar molecules and materials.