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Preparation and properties of cationic membranes obtained by radiation grafting of methacrylic acid onto PTFE films
Author(s) -
Hegazy ElSayed A.,
Taher N. H.,
Kamal H.
Publication year - 1989
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1989.070380704
Subject(s) - grafting , methacrylic acid , polymer chemistry , tetrafluoroethylene , copolymer , swelling , materials science , cationic polymerization , membrane , polymerization , monomer , polyelectrolyte , chemistry , chemical engineering , nuclear chemistry , polymer , composite material , biochemistry , engineering
Abstract Cationic membranes were prepared by direct radiation grafting of methacrylic acid (MAA) onto poly(tetrafluoroethylene) (PTFE) films followed by alkaline treatment to confer ionic character in the graft copolymer. The complete inhibition of homopolymerization of MAA by using ammonium ferreous sulfate (Mohr's salt) failed. However, the addition of 0.5 wt % FeCl 3 to the monomer solution effectively inhibited the homopolymerization process and higher grafting yield was obtained. It was found that the graft polymerization proceeded successfully in presence of methanol/water mixture (30/70 wt %), and much higher degrees of grafting were obtained as compared with those in the presence of other diluents used here. The influence of irradiation atmosphere (air, N 2 gas, and vacuum) on the grafting process was investigated. The dependence of the grafting rate on MAA concentration was found to be of orders 2.9 and 0.72 in the presence of 0.5 wt % Mohr's salt or 0.5 wt % FeCl 3 , respectively. This grafting system proceeds by the front mechanism. Investigation of mechanical properties, electrical conductivity, and swelling behavior of the grafted films revealed that such a copolymer could be acceptable in practical use as a cation‐exchange membrane.