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  • 1
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2605-2612 
    ISSN: 0887-624X
    Keywords: complex formation ; PEO ; copolymer ; phenolic resin ; hydrogen bonding ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Comb copolymers formed from acrylamide and poly(ethylene-glycol) methacrylate macro-monomer (PAM-co-PEG) were compared to poly(ethylene oxide) (PEO) with respect to hydrogen bond complex formation with water-borne phenolic resins. The behaviors of the two types of high molecular weight polyethers were similar. Complex formation gave a transient increase in viscosity followed by precipitation. Copolymers with pendant PEG chain lengths ≥ 9 formed complexes with phenolic resin whereas PEG homopolymer with a molecular weight of 2000 did not form a complex. For both copolymer and high molecular weight PEO, the tendency of the complex to precipitate increased when the pH was decreased from 7 to 4. Acridine orange, a cationic dye, bound to the phenolic resin and, after the addition of PEO, yielded visible complex gels with diameters about 20 μm. © 1995 John Wiley & Sons, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 19 (1998), S. 241-246 
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly(2-methoxy-4-vinylphenol), polyMVP, and poly[(sodium 4-styrenesulfonate)-co-(2-methoxy-4-vinylphenol)], poly(SSS/MVP), were synthesized by radical polymerization using Vazo-64 or tributylborane as initiator. Poly(3,4-dihydroxystyrene) and poly[(sodium 4-styrenesulfonate)-co-(3,4-dihydroxystyrene)] were obtained by demethylation of polyMVP and poly(SSS/MVP) using HBr and trimethylsilyl iodide, respectively. (Co)polymer structures were confirmed by 1H and 13C NMR spectra. About 30 wt.-% gel formed in the polyMVP polymerizations, whereas only a small amount (0.5 mol-%) of gel formed in the copolymerizations.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 54 (1994), S. 805-813 
    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: The synthesis of polyacrylamide (PAM) graft poly(ethylene oxide) (PEO) has been investigated and the reaction conditions were varied by gamma irradiation to optimize polystyrene latex flocculation by the copolymers. The effects of the gamma ray dosage, the PEO chain length, the ratio of PEO to PAM, and the crosslinking degree of copolymer were studied. The most effective flocculant was obtained by exposing a mixture of 1.2 wt % PAM (Mw = 5 × 106) and 0.94 wt % PEO (Mw = 5000) to 816 krad of gamma radiation. The resulting copolymer contained 24 wt % PEO. Crosslinking to give insoluble gels was an undesirable side reaction increased with γ-ray dose and decreased with PEO addition. The most effective flocculants contained more than 15 wt % PEO with little crosslinking. The grafting behavior of triblock copolymer, poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (EmPnEm, where m and n are oxyethylene and oxypropylene unit, respectively), onto PAM by gamma radiation was also studied; grafting occurred but effective flocculants were not obtained. © 1994 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1042-7147
    Keywords: colloidal silica modification ; electrostatic stabilization ; radical grafting ; hydrosilylation ; steric stabilization ; 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
    Notes: Colloidal silica sols having a narrow dispersity, prepared by the ammonia-catalyzed hydrolysis of Si(OEt)4, were functionalized by reaction with vinyltrimethoxysilane (H2C=CHSi(OMe)3) or methacryloxypropyltri-methoxysilane (H2C=CMeCO2(CH2)3Si(OMe)3. The electrostatically stabilized colloids were stable in acetone and dimethylformamide. Radical polymerization of methyl methacrylate in the presence of either type of functionalized particle led to particles with surfacegrafted poly(methyl methacrylate) (PMMA). The efficiency of polymer grafting was shown to be related to the nature of the functional groups. The PMMA-modified, sterically stabilized particles were colloidally stable in solvents ranging from acetone to toluene but unstable in water or hexane. The vinyl functionalized silica was alternatively reacted with HSiMe2-terminated silicones in a platinum-catalyzed hydrosilylation. The resultant sterically stabilized particles were stable in hexane. It was thus possible to convert the unmodified silica to organo-functionalized silica and finally to polymer-grafted silica while maintaining colloidal stability. During the course of these modifications, the mechanism for colloidal stability changed from electrostatic to steric stabilization.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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