Abstract: Thermally-reversible polymer compositions are obtained by reacting compounds with isocyanate and labile-hydrogen functionality. Aromatic polyimide, aromatic polycarbonate, polyarylsulfide, aromatic polyester with liquid crystal property, and polyarylimidazolidine oligomers are incorporated into the isocyanate or labile hydrogen compounds to give high-performance characteristics. Such thermally-reversible isocyanate-based polymer compositions with high-performance characteristics are useful, among other things, as finish surface coatings on composite materials such as polypropylene and polyethylene terephthalate. Novel phenolic-hydroxyl terminated polyarylsulfide and polyarylimidazolidine oligomers and their preparation are also described.

Abstract: Thermally-reversible polymer compositions are obtained by reacting compounds with isocyanate and labile-hydrogen functionality. High-performance characteristics are incorporated into the polymer by using aromatic polycarbonate, aromatic polyester, polyarylsulfide, and polyarylimidazolidine oligomers. The compositions are useful as hot-melt adhesives, coatings and especially finish surface coatings on composite materials such as polypropylene and polyethylene terephthalate, moldings and in injection reaction molding applications and composite and laminate fabrication.

Abstract: An end of life indicator for use in a toilet cistern with an ambient solution containing an active disinfectant component. The end of life indicator comprises a core of water soluble dyestuff surrounded by a polymer resistant to bleaching by said disinfectant solution. Upon the depletion of the active disinfectant component surrounding the end of life indicator, the alkalinity of the solution increases to a predetermined level whereupon hydrolysis of the polymer coating continues until water penetrates or dissolves the coating sufficiently to come into contact with the water soluble dye.

Abstract: The invention provides a novel efficient method for the preparation of a polyarylene sulfide or, typically, polyphenylene sulfide by the reaction of an alkali metal sulfide, e.g. Na.sub.2 S, and a polyhalogenated aromatic compound, e.g. 1,4-dichlorobenzene. The improvement in the inventive method comprises performing the reaction in a heterogeneous reaction mixture comprising water and a polyethyleneglycol having a relatively high molecular weight, namely an average molecular weight of from 2,000 to 20,000, and not freely miscible with water. The product polymer is outstandingly free from salt impurities, e.g. sodium chloride, as a byproduct of the reaction. When a low molecular polyethyleneglycol is added to the reaction mixture in combination with the above mentioned high molecular polyethyleneglycol, a remarkable catalytic effect is obtained to accelerate the reaction and increase the yield of the desired polymer product.