Abstract: Thermoplastic resin blends comprised of polyphenylene ether resin, homopolystryene and hydrogenated block copolymer characterized by low melt viscosity and high impact strength are described.

Abstract: A process for producing polyphenylene oxide which comprises contacting a phenolic monomer with oxygen in the presence of a catalyst composed of a manganese (II) salt and an ortho-hydroxyazo compound represented by the following formula: ##STR1## wherein A and B represent identical or different arylene ring having a valency of at least 2 and having an oxy group and an azo group directly linked to the ortho carbon atoms of the arylene ring and R represents hydrogen or lower alkyl group, or in the presence of said catalyst and an amine, in a polymerization solvent containing a base and thereby subjecting said phenolic monomer to an oxidative polymerization.