Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    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
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022898926567
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Kinetic study of preirradiation grafting of acrylic acid onto poly(tetrafluoroethylene-perfluorovinyl ether) copolymer (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 597-604 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A kinetic study has been made on the preirradiation grafting of acrylic acid (AAc) onto poly(tetrafluoroethylene-perfluorovinyl ether) (PFA) film. The effect of grafting conditions was investigated. The dependences of the grafting rate on preirradiation dose and monomer concentration was found to be of the order of 0.5 and 1.3, respectively. The final degree of grafting was found to increase with dose and monomer concentration. However, it decreases as the grafting temperature increase. The overall activation energy for the graft polymerization was calculated from Arrhenius plots to be 5.6 kcal/mol. The activation energy for this grafting system was found to be independent of preirradiation dose used in the range from 10 to 100 kGy. The relationship between the grafting rate and film thickness gave a negative first-order dependence. The results suggest that the grafting proceeds by radical mechanism with bimolecular termination of growing chain radicals. It was reasonable concluded that this grafting proceeds from the surface to the center of film with progressive monomer diffusion through the grafted layer which swells in the monomer solution.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170220309
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Membranes obtained by preirradiation grafting of acrylic acid onto poly(tetrafluoroethylene-perfluorovinyl ether) (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 3673-3685 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Some properties of the membranes obtained by preirradiation grafting of acrylic acid onto poly(tetrafluoroethylene-perfluorovinyl ether) copolymer (PFA) films have been investigated. The dimensional change caused by grafting and swelling behavior, water uptake, electrical conductivity, and mechanical properties of the grafted films were found to increase as the grafting proceeds. The influence of the preparation conditions (such as preirradiation dose, monomer concentration, grafting temperature, and film thickness) on those properties was studied. These properties were found to be dependent mainly on the degree of grafting regardless of grafting conditions, except at higher monomer concentration (〉40 wt %). The electric conductivity and mechanical properties for the membranes obtained at higher AAc concentrations were lower than those obtained at lower ones. Analysis by x-ray microscopy of the grafted films revealed that the grafting begins at the part close to the film surface and proceeds into the central part with progressive diffusion of monomer to give finally homogeneous distribution of the electrolytes in the whole bulk of the polymer. The membranes show good electrochemical and mechanical properties which make them acceptable for practical use as cation-exchange membranes.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170221205
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Preirradiation grafting of N-vinyl-2-pyrrolidone onto poly(tetrafluoroethylene) and poly(tetrafluoroethylene-hexafluoropropylene) films (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 493-502 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preirradiation grafting of N-vinylpyrrolidone (NVP) onto poly(tetrafluoroethylene) (PTFE) and poly(tetrafluoroethylene-hexafluoropropylene) (FEP) films was investigated. The influence of grafting parameters such as preirradiation dose, monomer concentration, and grafting temperature on the rate and grafting yield was studied. Different solvents were used for diluting the monomer and it was found that the aqueous monomer solution at a concentration of 80 wt% was suitable for this grafting system. However, the graft polymerization of NVP in benzene terminated within a short time without significant grafting yield. The dependence of the grafting rate on preirradiation dose and monomer concentration was 1.2 and 1.07 order, respectively, for grafting onto PTFE films and 1.1 and 1.2 order, respectively, for grafting onto FEP films. Arrhenius plots for grafting onto PTFE films showed a breaking point at ca. 35°C and the overall activation energies were calculated as 23.6 and 9.0 Kcal/mol below and above 35°C, respectively. For grafting onto FEP films, however, no break was observed in the Arrhenius plots; the overall activation energy was 11.9 Kcal/mol. The swelling behavior and electric resistance of the grafted materials were investigated.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170220219
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    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
    Keywords: radiation grafting ; vinyl acetate ; fluoropolymer ; DTA ; mechanical properties ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: 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.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210330308
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    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
    Keywords: graft copolymerization ; radiation ; PP ; vinyl acetate ; N-vinylpyrrolidone ; DSC ; properties ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: 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.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1995.210360108
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Study on radiation grafting of acrylic acid onto fluorine-containing polymers. II. Properties of membrane obtained by preirradiation grafting onto poly(tetrafluoroethylene) (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 26 (1981), S. 3871-3883 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Some properties of the membranes obtained by the preirradiation grafting of acrylic acid onto poly(tetrafluoroethylene) (PTFE) film have been studied. The dimensional change by grafting and swelling, water uptake, electric conductivity, and mechanical properties of the grafted PTFE films were measured and were found to increase as the grafting proceeds. These properties were found to be dependent mainly on the degree of grafting regardless of grafting conditions except higher monomer concentration (80 wt %). The electric conductivity and mechanical properties of the membranes at 80 wt % monomer concentration is lower than those at a lower monomer concentration. The results suggest that the membranes obtained at 80-wt % acrylic acid solution have a somewhat heterogeneous distribution of electrolyte groups as compared with those prepared at a monomer concentration less than 60 wt %. X-ray microscopy of the grafted films revealed that the grafting begins at the part close to the film surface and proceeds into the center with progressive diffusion of monomer to give finally the homogeneous distribution of electrolyte groups. The membranes show good electrochemical and mechanical properties which make them acceptable for the practical uses as cation exchange membrane.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1981.070261132
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    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
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: 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.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1989.070380704
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Radiation-induced oxidative degradation of isotactic polypropylene (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 26 (1981), S. 1361-1372 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Gas evolution, oxygen consumption, and change of mechanical properties were studied for the γ-ray irradiation of isotactic polypropylene from 60Co under various conditions, such as vacuum, air, and oxygen at room temperature. For irradiation under vacuum, G(H2) = 2.9 and G (CH4) = 0.09; the G values for other gases were very small. In the presence of oxygen, G(H2) was the same, and the G values for other hydrocarbons were two times those under vacuum. The G values of oxidative products and oxygen consumption were G(CO2) = 2.5, G(CO) = 1.1, and G(O2) = 50 at oxygen pressure of 500 torr and were dependent on oxygen pressure. With irradiation under vacuum at 2-3 Mrad, mechanical properties scarcely changes immediately after irradiation but degrade gradually with storage time in air at room temperature.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1981.070260427
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Radiation grafting of acrylic acid onto fluorine-containing polymers. I. Kinetic study of preirradiation grafting onto poly(tetrafluoroethylene) (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 26 (1981), S. 3117-3124 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Preirradiation grafting of acrylic acid onto poly(tetrafluoroethylene) film was studied. The trapped radicals formed upon irradiation are able to induce graft polymerization under appropriate conditions. The influence of the grafting conditions were analyzed kinetically. The grafting reaction begins close to the film surface and proceeds into the center with progressive monomer diffusion through the grafted layer. The dependences of the grafting rate on preirradiation dose and monomer concentration were found to be 0.2 and 1.1 order, respectively. The overall activation energies for this grafting were calculated to be 15.2 and 4.8 kcal/mol below and above 35°C, respectively. The relationship between the grafting rate and film thickness gave a negative first-order dependence.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1981.070260925
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...