(DE19548425-A1)      Polyarylene sulphide-sulphonic acids which are soluble in polar aprotic solvents are new.    Also claimed is the prepn. of the acids, comprising completely dissolving the polyarylene sulphide in chloro sulphonic acid, opt. adding oleum or acetic anhydride, and then precipitating the prod. in an aq. medium.    USE -   Used in the prodn. of coatings, mouldings, films, membranes (esp. for micro-, nano- or ultra-filtration) or fibres, or as materials for condensers or electrochemical cells, esp. fuel or electrolysis cells.    ADVANTAGE -   The ion-exchange prods. are soluble in, e.g., N-methyl pyrrolidone (NMP), DMAC, DMSO or DMF. Polyarylene sulphides such as Fortron and Ryton (both RTMs) can therefore be modified to give prods. suitable for direct mfr. of the above membranes. The modified prods. have 0.1-100 mol.% of their repeating units sulphonated and 0-40 mol.% chlorinated, opt. with some or all of the S linkages oxidised to SO2. The membranes have a proton conductivity of 2-200 mS/cm.    (EP840760-A1)      Polyarylene sulphide-sulphonic acids which are soluble in polar aprotic solvents are new.    Also claimed is the prepn. of the acids, comprising completely dissolving the polyarylene sulphide in chloro sulphonic acid, opt. adding oleum or acetic anhydride, and then precipitating the prod. in an aq. medium.    USE -   Used in the prodn. of coatings, mouldings, films, membranes (esp. for micro-, nano- or ultra-filtration) or fibres, or as materials for condensers or electrochemical cells, esp. fuel or electrolysis cells.    ADVANTAGE -   The ion-exchange prods. are soluble in, e.g., N-methyl pyrrolidone (NMP), DMAC, DMSO or DMF. Polyarylene sulphides such as Fortron and Ryton (both RTMs) can therefore be modified to give prods. suitable for direct mfr. of the above membranes. The modified prods. have 0.1-100 mol.% of their repeating units sulphonated and 0-40 mol.% chlorinated, opt. with some or all of the S linkages oxidised to SO2. The membranes have a proton conductivity of 2-200 mS/cm.    (JP11510198-W)      Polyarylene sulphide-sulphonic acids which are soluble in polar aprotic solvents are new.    Also claimed is the prepn. of the acids, comprising completely dissolving the polyarylene sulphide in chloro sulphonic acid, opt. adding oleum or acetic anhydride, and then precipitating the prod. in an aq. medium.    USE -   Used in the prodn. of coatings, mouldings, films, membranes (esp. for micro-, nano- or ultra-filtration) or fibres, or as materials for condensers or electrochemical cells, esp. fuel or electrolysis cells.    ADVANTAGE -   The ion-exchange prods. are soluble in, e.g., N-methyl pyrrolidone (NMP), DMAC, DMSO or DMF. Polyarylene sulphides such as Fortron and Ryton (both RTMs) can therefore be modified to give prods. suitable for direct mfr. of the above membranes. The modified prods. have 0.1-100 mol.% of their repeating units sulphonated and 0-40 mol.% chlorinated, opt. with some or all of the S linkages oxidised to SO2. The membranes have a proton conductivity of 2-200 mS/cm.    (EP840760-B1)      Polyarylene sulphide-sulphonic acids which are soluble in polar aprotic solvents are new.    Also claimed is the prepn. of the acids, comprising completely dissolving the polyarylene sulphide in chloro sulphonic acid, opt. adding oleum or acetic anhydride, and then precipitating the prod. in an aq. medium.    USE -   Used in the prodn. of coatings, mouldings, films, membranes (esp. for micro-, nano- or ultra-filtration) or fibres, or as materials for condensers or electrochemical cells, esp. fuel or electrolysis cells.    ADVANTAGE -   The ion-exchange prods. are soluble in, e.g., N-methyl pyrrolidone (NMP), DMAC, DMSO or DMF. Polyarylene sulphides such as Fortron and Ryton (both RTMs) can therefore be modified to give prods. suitable for direct mfr. of the above membranes. The modified prods. have 0.1-100 mol.% of their repeating units sulphonated and 0-40 mol.% chlorinated, opt. with some or all of the S linkages oxidised to SO2. The membranes have a proton conductivity of 2-200 mS/cm.    (US6096856-A)      Polyarylene sulphide-sulphonic acids which are soluble in polar aprotic solvents are new.    Also claimed is the prepn. of the acids, comprising completely dissolving the polyarylene sulphide in chloro sulphonic acid, opt. adding oleum or acetic anhydride, and then precipitating the prod. in an aq. medium.    USE -   Used in the prodn. of coatings, mouldings, films, membranes (esp. for micro-, nano- or ultra-filtration) or fibres, or as materials for condensers or electrochemical cells, esp. fuel or electrolysis cells.    ADVANTAGE -   The ion-exchange prods. are soluble in, e.g., N-methyl pyrrolidone (NMP), DMAC, DMSO or DMF. Polyarylene sulphides such as Fortron and Ryton (both RTMs) can therefore be modified to give prods. suitable for direct mfr. of the above membranes. The modified prods. have 0.1-100 mol.% of their repeating units sulphonated and 0-40 mol.% chlorinated, opt. with some or all of the S linkages oxidised to SO2. The membranes have a proton conductivity of 2-200 mS/cm.