Abstract: A process for producing a polyphenylene sulfide ketone polymer comprising reacting a dihalogen compound of the general formula ##STR1## wherein X and X', which may be the same or different, each represents a fluorine, chlorine, bromine or iodine atom, with an alkali metal sulfide in a polar solvent in such a way that the alkali metal sulfide is not deprived of free water or the water of hydration in the polar solvent before polymerization is started, and that the reaction is performed at a temperature in the range of from 80.degree. to 170.degree. C. in the initial period of polymerization until the percentage of residual unreacted dihalogen compound is reduced to 2% or below, with the subsequent reaction being performed at a temperature in the range of from 200.degree. to 345.degree. C.

Abstract: A class of amide group-containing aromatic dihalide compounds are sulfidized to provide a novel class of aromatic sulfideamide polymers increased in crystalline melting point (T.sub.m). The polymers exhibit excellent resistance to high temperatures, resistance to solvents, flame-retardant properties and improved mechanical properties.

Abstract: A class of amide group-containing aromatic dihalide compounds are sulfidized together with a class of aromatic dihalide compounds to provide a novel class of aromatic sulfideamide polymers increased in crystalline melting point (T.sub.m). The polymers exhibit excellent resistance to high temperatures, resistance to solvents, flame-retardant properties and improved mechanical properties.

Abstract: In a process in which a poly (arylene sulfide) is synthesized by reacting a dihaloaromatic compound and an alkali metal sulfide in a polar organic solvent, the curing ability of the product polymer is significantly enhanced by introducing a small proportion of a hydroxyl group-containing polyhaloaromatic compound to the reaction mixture when a conversion of at least 60% has been achieved with respect to the dihaloaromatic compound present in the reaction mixture. The product polymer may be advantageously employed in various molding, forming or coating processes to provide the produced articles with increased strengths. The hydroxyl groups introduced into the polymer enable the polymer to be modified, if desired.

Abstract: A polyarylene sulfide having a high molecular weight is produced at low cost and without causing any pollution problems through a polymerization reaction between a dihalogenated aromatic compound and an alkali metal sulfide in an aprotic polar solvent by adding from about 0.05 to about 5 moles of calcium chloride per mole of the dihalogenated aromatic compound after the conversion of the dihalogenated aromatic compound has reached about 60 to about 98 mol % and allowing the reaction to proceed. Such a polyarylene sulfide is very useful for utilization in extrusion of films, fibers, etc.