Plasma graft polymerization of N,N-dimethylaminoethyl methacrylate and water–ethanol separation by pervaporation through the grafted membranes

Authors

  • Toshihiro Hirotsu,

    Corresponding author
    1. Research Institute for Polymers and Textiles, 1-1-4, Higashi, Tsukuba, Ibaraki 305, Japan
    • Research Institute for Polymers and Textiles, 1-1-4, Higashi, Tsukuba, Ibaraki 305, Japan
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  • Akito Arita

    1. Research Institute for Polymers and Textiles, 1-1-4, Higashi, Tsukuba, Ibaraki 305, Japan
    Current affiliation:
    1. Fukuoka Station of Industry Tests, 332, Kamikoga, Chikushino, Fukuoka 818, Japan
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Abstract

N,N-dimethylaminoethyl methacrylate was graft-polymerized onto the porous polypropylene films of Celgard 2400 and 2500 which have been previously surface-activated by glow discharge plasmas. The grafting was dependent on various factors both in the plasma pretreatment and the post-polymerization with the monomer. The reaction was discussed from the aspects of the dependences of graft polymerization on discharge power, plasma pretreatment period, etc. When the grafting exceeded a critical amount depending on the size of pores on the substrate film, pervaporation of water-ethanol separation functioned through these grafted membranes. The water permselectivity was improved by the ammonium ionization of the pendant N,N-dimethylamino group using dimethyl sulfate or chloroacetic acid, although the increase of prevaporation performance was not so high as those previously obtained by the grafted poly(sodium acrylate) -type membranes. Pervaporation characteristics of these membranes were discussed from the ionized states of the permselective layers analyzed by IR and ESCA.

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