Polyphenylene sulfide/polyphenylene sulfide sulfone block copolymer

Claim 1

A process for producing a block copolymer composed of polyphenylene sulfide segments and polyphenylene sulfide sulfone segments and having a logarithmic viscosity (η) of 0.03 to 1.0, said logarithmic viscosity (η) being determined at 206° C. for its solution in alpha-chloronaphthalene in a polymer concentration wherein said polyphenylene sulfide segments consist of at least 70 mole % of p-phenylene sulfide units and said polyphenylene sulfide sulfone segments consist of at least 90 mole % of phenylene sulfide sulfone segments, of 0.4 g/100 ml of solution and calculated in accordance with the equation (η)=ln (relative viscosity)/polymer concentration, which comprises reacting a polyphenylene sulfide prepolymer with a mixture of a dihalodiphenylsulfone and a sulfidization agent, or a polyphenylene sulfide sulfone prepolymer with a mixture of a polyhalogenated aromatic compound and a sulfidization agent, in a polar solvent select from the group consisting of N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methyl-epsilon-caprolactam, hexamethylphosphoramide and mixtures thereof wherein said polyphenylene sulfide prepolymer consists essentially of at least 70 mole % of structural units represented by the formula ##STR31## and not more than 30 mole % of structural units selected from the group consisting of ##STR32## wherein R represents an alkyl group, a nitro group, a phenyl group, an alkoxy group, a carboxylic acid group or a metal carboxylate group, and wherein said polyphenylene sulfide sulfone prepolymer consists essentially of at least 90 mole % of structural units represented by the formula ##STR33## wherein groups bonded to both terminals of the polymer are ortho- or para- to the sulfone group, R 1 and R 2 represent hydrogen or a C 1 -C 8 alkyl group /or an aryl group, and a and b are integers of 0 to 4, and not more than 10 mole % of structural units selected from the group consisting of ##STR34## wherein R represents an alkyl group, a nitro group, a phenyl group, a carboxylic acid group or a metal carboxylate group.