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  • 1
    Electronic Resource
    Electronic Resource
    Some aspects of inverse emulsion copolymerization of acrylamide with methacrylic acid (1985)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 10 (1985), S. 199-214 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Inverse emulsion copolymerization studies of acrylamide (Am) with methacrylic acid (MAA) are reported. Aqueous monomer emulsions in toluene were prepared with a blend of two surfactants (sorbitan sesquioleate - Cl8 - terminated acrylamide oligomers). Polymerization kinetics in presence of an oil soluble initiator (AIBN) were determined at 40°C as function of MAA content and aqueous phase pH : monomer reactivity ratios have been derived as rAm = 0.58 ± 0.02, rMAA = 4.40 ± 0.10 at pH 4 and rAm = 0.56 ± 0.005, rMAA = 0.15 ± 0.03 at pH 10. Particle size and stability of inverse monomer emulsions and final latexes were found to depend upon the aqueous phase pH, as well as the intrinsic viscosities of the copolymers; this suggests differences in polymerization mechanism versus the pH.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1985.020101985116
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Inverse emulsion polymerization of acrylamide. I. Contribution to the study of some mechanistic aspects (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 427-449 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The inverse emulsion polymerization of aqueous solution of acrylamide in toluene has been studied at 40°C using a blend of surfactants as emulsifying system and oil soluble azo initiators. The azo compound partition between the phases has been measured and the effects of their nature and concentration on the polymerization kinetics have been investigated. The influence of other parameters on the kinetics and particle size of the inverse latex have also been investigated: the nature and amount of the emulsifier system, the stirring rate, and the presence of oil-soluble inhibitor. The particle-size analysis using electron microscopy or dynamic light-scattering methods showed the presence of two populations of particles in the initial monomer emulsion and in the final inverse latex: one with very tiny particles (20 nm diam) and the other with larger particles (80-400 nm diam) which is highly polydispersed. The average size of these large particles undergoes a sharp decrease at a certain percent conversion depending upon the stirring rate. The evolution of the particle size distribution may result from a balance between coalescence and dispersion of the emulsion droplets under the effect of prevailing shear rate due to agitation.Concerning the initiation process, the very low solubility of the azo compound in the aqueous solution, together with the effect of the stirring rate and the presence of an oil-soluble inhibitor on the polymerization kinetics lead to the conclusion that most of the initiaton originates from the capture of radicals or oligomeric radicals produced in the oil phase or in the interfacial layer.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1986.080240304
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Study of the thermal decomposition of potassium persulfate by potentiometry and capillary electrophoresis (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 1271-1281 
    Details
    ISSN: 0887-624X
    Keywords: potassium persulfate ; decomposition ; soap-emulsified systems ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two methods of analysis, potentiometry and capillary electrophoresis, were used to study the decomposition of potassium persulfate (KPS) in aqueous solutions. The experiments were carried out in a glass reactor equipped with continuous control of temperature and pH during the reaction. The effect of the pH on the decomposition of KPS was investigated. The rate of KPS decomposition in the presence of a variety of additives (surfactants, inhibitor, monomer-like molecules, and monomers), which are used in emulsion polymerization recipes, was also studied over the temperature range of interest. The rate of disappearance of the persulfate ion was greatly increased in the presence of hydroquinone, but changed very little in the presence of surfactants. © 1996 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 4
    Electronic Resource
    Electronic Resource
    Inverse emulsion polymerization of acrylamide. II. Synthesis and characterization of copolymers with methacrylic acid (1987)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 25 (1987), S. 1127-1161 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Inverse emulsion copolymerization studies of acrylamide (Am) with methacrylic acid (MAA) are reported. Aqueous monomer solutions were emulsified in toluene with a blend of two surfactants (sorbitan sesquioleate and C18-terminated acrylamide oligomers). Polymerization kinetics in presence of an oil-soluble initiator (AIBN) were determined at 40°C as a function of methacrylic acid content and aqueous-phase pH. Polymerization rates were found to be faster at basic pH than at acidic pH, which appeared to be related to the actual concentration of methacrylic acid in the aqueous phase. Monomer reactivity ratios have been derived as rA-M = 0.58 ± 0.02 and rM-A = 4.0 ± 0.10 at pH 4, rA-M = 0.56 ± 0.005 and rM-A = 0.15 ± 0.03 at pH 10. These differences were found to have an effect on the molecular characteristics of the copolymers. Initial emulsions and final inverse latexes displayed the same broad size distribution; under basic pH the particle size is relatively insensitive to the ionic comonomer concentration. Poor latex stability is characteristic of copolymer latexes prepared under acidic conditions. Based on these experimental results, some aspects of the polymerization mechanism are discussed.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1987.080250418
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    Paper (German National Licenses)
    Fulltext
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