Radiation grafting of acrylic and methacrylic acids onto poly(tetrafluoroethylene‐hexafluoropropylene‐vinylidene fluoride) TFB films

Abstract

SYNOPSISA study has been made for the preparation of membranes by the direct radiation grafting of acrylic and methacrylic acids onto poly ( tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride) TFB films. The appropriate reaction conditions were selected under which the graft polymerization was carried out successfully. In this grafting system, ammonium ferrous sulfate ( Mohr's salt), ferric chloride, and cuppric chloride were used as inhibitors to minimize the homopolymerization of acrylic acid and methacrylic acid. Also, the effect of monomer concentration on the rate of grafting was investigated. The dependence of the grafting rate on monomer concentration was found to be of the order of 1.1 and 1.0 for acrylic acid and methacrylic acid, respectively. This grafting system was proceeded by a front mechanism. Some selected properties of the grafted films such as swelling behavior, dimensional change, and mechanical and electrical properties were investigated. It was found that the grafted membranes possess good hydrophilic properties that may make them promising in some practical applications. 0 1993 John Wiley & Sons, Inc.I NTRO DUCT10 N Fluorine-containing polymers are appropriate in preparing membranes for separation processes because of their good thermal, mechanical, and chemical resistance. The hydrophobic character of the fluoropolymers can be overcome by radiation-initiated grafting of hydrophilic monomers onto these polymers.'-" The nature and morphological peculiarities of the trunk polymers as well as the grafting reaction parameters affect the membrane properties of the grafted films. The most important applications of these synthetic membranes are in industrial mass separation processes such as micro-, ultra-, and hyperfiltration, electrodialysis, and gas separation. However, a considerable amount of research is being conducted to develop membranes for many other uses such as enzyme reactors, electrochemical power sources, and ion-selective electrodes and for the controlled release of active agents in the medical * To whom correspondence should be addressed. Many studies were carried out in our laboratories devoted to the search for new and improved membrane compositions using almost every available polymeric materia1.'2-23 The preparation and selected properties of neutral, cationic, and anionic membranes obtained by radiation-initiated grafting of hydrophilic monomers onto different trunk polymers using the direct and postradiation techniques were investigated. These grafted membranes showed great promise for practical applications.In the present study, the preparation and properties of membranes obtained by direct radiationinduced graft polymerization of acrylic and methacrylic acid solutions onto TFB films were investigated. The effect of grafting conditions on the grafting process and inhibition of homopolymerization was investigated. Some selected properties of the graft films such as water uptake, dimensional changes, electrical conductivity, and mechanical properties were investigate...

Synthesis and characterization of acrylic acid‐grafted hydrocarbon and fluorocarbon polymers with the simultaneous or mutual grafting technique

“…This is attributed to the point at which the graft penetrates through to the center of the film from both sides, creating a pathway by which the conducting species can travel through the thickness of the copolymer. The results support the accepted stepwise grafting front theory 10 for the formation of this class of copolymers. It can be seen from the figures that the breakthrough grafting point is dependent more on the chemical nature of the polymer film (whether fluorocarbon or hydrocarbon) than on its thickness.…”

“…The grafting solutions were made with different concentrations of acrylic acid (10,20, and 30 vol %) with demineralized water as a diluent. The grafting solution was purged with nitrogen, and the samples were irradiated at 166 Gy h Ϫ1 for 60 h to a total dose of 10 kGy.…”

Physicochemical investigation of radiation‐grafted poly(acrylic acid)‐graft‐poly(tetrafluoroethylene–ethylene) copolymer membranes and their use in metal recovery from aqueous solution

“…Meanwhile, the physical properties, such as the swelling behavior in water and dimensional change, were studied previously. 8 …”

Radiation‐Induced Graft Copolymerization of Styrene into Tetrafluoroethylene‐Hexafluoropropylene‐Vinylidene Fluoride (THV) Terpolymer Films

“…To the best of our knowledge, only two articles have been published on the radiation grafting into THV polymers. These articles describe the radiation‐induced grafting of acrylic acids and N ‐vinylpyrrolidone, respectively, into THV films 15, 16…”