摘要:
A method for producing a cyclic polyarylene sulfide, wherein a cyclic polyarylene sulfide is produced by heating a reaction mixture which is composed of at least a linear polyarylene sulfide (a), a sulfidizing agent (b), a dihalogenated aromatic compound (c) and an organic polar solvent (d). This method for producing a cyclic polyarylene sulfide is characterized in that not less than 1.25 liters of the organic polar solvent is used per 1 mole of the sulfur content in the reaction mixture. This method enables to efficiently produce a cyclic polyarylene sulfide, more specifically cyclic oligoarylene sulfide by an economical and simple process in short time.
摘要:
Molded articles of an aromatic polymer are described having at least a portion of the surface layer of the polymer modified by a heterogeneous reaction of the solid polymer and a reactive solution. The polymer to be treated may contain different repeating units in the said surface layer. The treatment to produce the molded article may comprise casting, injection molding, extending or otherwise shaping the polymer to mold the polymer into a desired shape. The heterogeneous treatment to produce the heterogeneously modified molded article may comprise treating a surface layer of a flat cast sheet in the form of a flat membrane, spirally wound membrane, hollow fiber, or tubular material.