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  • 1
    Digitale Medien
    Digitale Medien
    Characterization and application of radiation grafted membranes in waste treatment (2000)
    Springer
    Czechoslovak journal of physics 50 (2000), S. 297-308 
    Details
    ISSN: 1572-9486
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Ionic membranes were prepared by radiation-induced grafting of acrylic acid onto low density polyethylene films. To elucidate the possibility of practical use, a study has been made for the characterization of the grafted and chemically treated membranes. The selectivity of such prepared membranes towards the chelation or complexation of different alkali metals was investigated, to find that the higher affinity is observed for K+, Na+ and Li+ ions compared to other alkali metals used. The metal uptake percent was determined using different techniques: flame photometer and X-ray fluorescence (XRF). The uptake of metal from its feed solution by the grafted membrane increased as the degree of grafting increased, i.e., it is directly proportional to the content of functional carboxylic acid groups in the graft copolymer. As a consequence, the electrical conductivity of metal feed solution decreased during such process of metal chelation by the membrane. The higher the grafting degree of membrane, the lower the electrical conductivity of metal feed solutions observed. The changes in thermal properties of the prepared membranes were investigated and characterized using differential scanning calorimeter (DSC), and thermal gravimetric analysis (TGA). The thermal stability of these membranes increased with a degree of grafting due to the formation of crosslinked network structure via hydrogen bonding. Furthermore, such stability is enhanced for the alkali-treated membranes even at high elevated temperatures. The prepared membranes showed a great promise for possible use in the recovery of uranium from zirconium in their wastes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1022898926567
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  • 2
    Digitale Medien
    Digitale Medien
    Radiation-induced graft polymerization of acrylic acid onto fluorinated polymers. I. Kinetic study on the grafting onto poly(tetrafluoroethylene-ethylene) copolymer (1992)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 1969-1976 
    Details
    ISSN: 0887-624X
    Schlagwort(e): radiation grafting ; kinetic and properties ; acrylic acid and fluoro polymer ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Direct radiation-induced grafting of aqueous acrylic acid (AAc) onto poly(tetrafluoroethylene-ethylene) (ET) film has been studied. The effect of grafting conditions such as monomer concentration, exposure dose, dose rate, and film thickness on the grafting yield was investigated. The dependence of the grafting rate on monomer concentration was found to be 1.2 order. The dependence of the grafting rate on dose rate was found to be 0.6 order regardless of the film thickness. The relationship between the grafting rate and film thickness gave a negative first-order dependence. The results suggest that the grafting process is mainly controlled by monomer diffusion, and it was concluded that this grafting system proceeded by the front mechanism. The swelling behavior increases linearly with degree of grafting. The electrical conductivity and mechanical properties for the trunk and grafted polymer were investigated at different irradiation doses in air and under vacuum irradiations. © 1992 John Wiley & Sons, Inc.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1992.080300920
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  • 3
    Digitale Medien
    Digitale Medien
    Radiation-induced graft polymerization of acrylic acid onto fluorinated polymers. II. Graft copolymer-metal complexes obtained by radiation grafting onto poly(tetrafluoroethylene-ethylene) copolymer (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 527-533 
    Details
    ISSN: 0887-624X
    Schlagwort(e): radiation grafting ; acrylic acid and fluoro polymers ; polymer-metal complexes ; properties ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A study has been made on the graft copolymers obtained by radiation-induced grafting of acrylic acid onto poly(tetrafluoroethylene-ethylene) (ET) films. The conversion of the graft copolymer into metal acrylate copolymer complex was carried out by treatment with different metal salts. Such a prepared graft copolymer-metal complex was confirmed by different methods: IR, UV spectrometry, degree of coloration, and x-ray fluorescence. Some selected properties of the graft copolymer-metal complexes such as electrical conductivity, swelling behavior, and mechanical properties were investigated. The influence of metal complexes in the graft copolymers was determined and compared with the grafted films. The possibility of the practical uses for such prepared graft copolymer-metal complexes was discussed and determined. It was assumed that such materials may be of great interest in the field of semiconducting materials in addition to their applicability as cation-exchange membranes. © 1993 John Wiley & Sons, Inc.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1993.080310225
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  • 4
    Digitale Medien
    Digitale Medien
    Radiation-induced graft polymerization of acrylamide I. Preparation conditions and gel determination for polyethylene-grafted films (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 1933-1942 
    Details
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Radiation-induced graft polymerization of acrylamide (AAm) onto low-density polyethylene(LDPE) film has been investigated. The appropriate reaction conditions at which the graft polymerization was carried out successfully were selected. It was observed that the grafting process was enhanced remarkably by using distilled water as diluent. In this grafting system ammonium ferrous sulphate (Mohr's salt) was used as inhibitor to minimize the homopolymerization of AAm and the suitable concentration of such inhibitor was found to be 3 wt %. The dependence of the grafting rate on the monomer concentration was calculated to be 2.9 order, regardless of the irradiation atmosphere (N2 gas or under vacuum). When the radiation grafting process was carried out under vacuum, higher degrees of grafting were obtained as compared to those in nitrogen gas or in air atmosphere. Network structure was formed in the graft copolymer and the gel formation was determined in the p-xylene-extracted grafted films. Results showed good evidence that the grafting process takes place by the front mechanism.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1986.080240815
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  • 5
    Digitale Medien
    Digitale Medien
    Preparation and properties of cationic membranes obtained by radiation grafting of methacrylic acid onto PTFE films (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 38 (1989), S. 1229-1242 
    Details
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: 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 % FeCl3 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, N2 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 % FeCl3, 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.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/app.1989.070380704
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  • 6
    Digitale Medien
    Digitale Medien
    Preparation and some properties of hydrophilic membranes obtained by radiation grafting of methacrylic acid onto fluorinated polymers (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 41 (1990), S. 2637-2647 
    Details
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Hydrophilic membranes were prepared by direct radiation grafting of methacrylic acid (MAA) onto poly(tetrafluoroethylene-perfluorovinylether) copolymer (PFA) and poly(tetrafluoroethylene-hexafluoropropylene) copolymer (FEP) films followed by alkaline treatment to confer ionic character in the graft copolymer. Addition of 0.5 wt % FeCl3 to the monomer solution effectively inhibited the homopolymerization process and higher grafting yield was obtained. The graft copolymerization of MAA was carried out in presence of methanol/water mixture (30/70 wt %) in nitrogen atmosphere irradiation. The dependence of the grafting rate on MAA concentration was found to be 0.63 and 0.94 order for PFA and FEP films, respectively. This grafting system proceeds by the front mechanism in which the monomer diffuses through the already grafted layer formed initially. Some selected properties of the graft copolymers were investigated. It was found that the grafted membranes possess good mechanical, electrical, and hydrophilic properties which may make them promising in some practical applications.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/app.1990.070411111
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  • 7
    Digitale Medien
    Digitale Medien
    Investigation of radiation grafting of vinyl acetate onto (tetrafluoroethylene-perfluorovinyl ether) copolymer films (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 33 (1994), S. 285-291 
    Details
    ISSN: 0959-8103
    Schlagwort(e): radiation grafting ; vinyl acetate ; fluoropolymer ; DTA ; mechanical properties ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: A study has been made of radiation-induced grafting of vinyl acetate (VAc) on to (tetrafluoroethylene-perfluorovinyl ether) copolymer (PFA). Effects of grafting conditions such as inhibitor and monomer concentrations and irradiation dose on the grafting yield were investigated. In this grafting system, ammonium ferrous sulphate (Mohr′s salt) was added to the monomer-solvent mixture to minimize the homopolymerization of VAc and the most suitable concentration was found to be 2.0 wt%. It was found that the dependence of the initial grafting rate on monomer concentration is of the order 1.5. The degree of grafting tends to level off at high irradiation doses due to the recombination of formed free radicals without initiating graft polymerization. Some properties of the prepared graft copolymer such as swelling behaviour, electrical conductivity, thermal and mechanical properties were also investigated. The electrical conductivity was improved by hydrolysis of poly(vinyl acetate) in the grafted chains to their respective vinyl alcohols. The tensile properties were improved by grafting; however, the elongation percent decreased. The DTA data showed thermal stability of such graft copolymers for temperatures up to 300°C, but stability decreased at higher temperatures.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pi.1994.210330308
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  • 8
    Digitale Medien
    Digitale Medien
    Preparation and thermal characterization of graft copolymer obtained by radiation grafting of individual and binary monomer systems (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 36 (1995), S. 47-56 
    Details
    ISSN: 0959-8103
    Schlagwort(e): graft copolymerization ; radiation ; PP ; vinyl acetate ; N-vinylpyrrolidone ; DSC ; properties ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Graft copolymers were obtained by radiation-induced grafting of vinyl acetate (VAc) and N-vinylpyrrolidone (NVP) individually and in binary mixture on to polypropylene (PP) films. The effect of some grafting conditions on the grafting yield was determined. The addition of Cu2Cl2 as inhibitor to the reaction medium inhibited the homopolymerization of the comonomer. The grafting process was remarkably enhanced by using dioxan as a diluent compared with other solvents used. The addition of some inorganic salts has a great influence on the individual grafting of both monomers. The gel percent in the graft copolymer was determined; it increased as the grafting yield increased. The swelling behaviour and electrical conductivity for the grafted films slightly increased by grafting. The changes in thermal parameters such as glass transition (Tg), melting (Tm) and recrystallization (Trc) temperatures and heats of melting (ΔHm) and recrystallization (ΔHrc) of the graft copolymers were also followed by differential scanning calorimetry (DSC). These thermal parameters of PP were varied by grafting with VAc and NVP and depend on the graft yield, which reflects the change in its crystalline domains and formation of crosslinks in the graft chains. The heat of recrystallization of the graft copolymer by cooling from the molten state decreases by grafting which is a good indication of crosslink formation, since crosslinking decreases the crystallizability of the polymer matrix.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pi.1995.210360108
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  • 9
    Digitale Medien
    Digitale Medien
    Radiation grafting of MMA onto PVC films (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 41 (1990), S. 2941-2950 
    Details
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: An approach to the problem of producing poly(vinyl chloride) (PVC) graft copolymer exhibiting good mechanical properties and electrical resistance that suits its uses as an electrical insulator has been investigated. Graft copolymerization of methyl methacrylate (MMA) onto PVC using γ-radiation as initiator has been studied. PVC was chemically modified, and the effect of the change in its chemical and physical structure on its properties was investigated. In this grafting system, different solvents were tried and it was found that the most suitable diluent for the grafting of MMA onto PVC films is methanol. An appreciable improvement in tensile properties of the graft copolymer was achieved. The most suitable degree of grafting, concerning electrical insulation efficiency, was found to be near 80%. Gel determination in the graft copolymer was carried out, and a crosslinked network structure was formed. Increasing the crosslinking content in the graft copolymer leads to a decrease in the extent of swelling due to the less diffusivity of the solutions through such network structure.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/app.1990.070411131
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  • 10
    Digitale Medien
    Digitale Medien
    Radiation-initiated graft copolymerization of individual monomer and comonomer onto polyethylene and polytetrafluoroethylene films (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 39 (1990), S. 1029-1043 
    Details
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Preparation and some properties of the graft copolymers obtained by radiation-induced graft polymerization of methacrylic acid (MAA) and (acrylonitrile/MAA) comonomer onto polyethylene and polytetrafluoroethylene films, were investigated. The effect of reaction conditions, solvent, monomer, and inhibitor concentration, comonomer composition, and comonomer concentration, on the graft copolymerization process was studied. The grafting process was enhanced in the presence of comonomer (AN/MAA) as compared with individual grafting of MAA or acrylonitrile (AN). The optimum comonomer composition, at which the highest grafting yield was obtained, was found to be (80/20) wt % of (AN/MAA) comonomer. The graft copolymerization of (AN/MAA) comonomer was enhanced in presence of AN due to its higher polarity strength. The electrical and swelling properties of the graft copolymers were greatly affected by the contents of PAN and PMAA graft chains. Mechanical properties of the graft copolymers were significantly changed with the grafting yield.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/app.1990.070390502
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