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  • 1
    Electronic Resource
    Electronic Resource
    Polymerization of monolayers. VI. Influence of the nature of the exchangeable ion on the tacticity of insertion poly(methyl methacrylate) (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 1681-1691 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The influence of the nature of exchangeable cations on the tacticity of poly(methyl methacrylate) (PMMA) prepared from montmorillonite-MMA adsorption complexes was investigated. The strength of ion-dipole interactions was estimated either by the value of the electrostatic interaction potential or by the value of the carbonyl-stretching frequency shift. It was shown that Pi, the percentage of isotactic triads in the polymer, increases with increasing strength of the ion-dipole interactions, while the persistence ratio and the mean length of closed isotactic (or syndiotactic) sequences remain essentially unchanged regardless of the nature of the cation. It was shown that values of Pi may vary from 0.15 for weakly interacting ions to 0.5 for strongly interacting ones, reaching at the upper limit the value calculated from the model proposed in a previous paper, thus confirming its validity.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160090910
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Polymerization of monolayers. V. Tacticity of the insertion poly(methyl methacrylate)Paper presented at the I.U.P.A.C. Macromolecular Symposium in Budapest, August 1969. (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1599-1615 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Insertion poly(methyl methacrylate) (PMMA) formed within a monolayer of monomer adsorbed on montmorillonite was studied by means of NMR spectroscopy and shown to be composed of short stereosequences with a predominant isotactic component. The stereospecificity of the insertion PMMA can be understood in terms of the organization of the monomer adsorbed on the surface of the mineral. The monolayer of monomer is assumed to be composed of monads and isotactic diads due to dipole-ion interactions between the molecules of methyl methacrylate and exchangeable cations. Results of experiments relating factors such as temperature, density of ion population of the surface, and the nature of ions are discussed. It is shown that the populations of isotactic and syndiotactic triads Pi and Ps determined experimentally in the insertion PMMA are in a reasonable agreement with values calculated from the model. It is shown, furthermore, that Pi increases with increase in the density of the ion population, in agreement with the equations derived from the model.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1970.160080913
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Polymerization of adsorbed monolayers. III. Preliminary structure studies in dilute solution of the insertion polymers (1966)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 4 (1966), S. 465-474 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Insertion poly(methyl acrylate) and poly(methyl methacrylate) were prepared from monomers adsorbed in monolayers on the surface of montmorillonite clay, both in the presence and in the absence of bifunctional crosslinkers (ethylene glycol dimethacrylate and tetramethylene glycol dimethacrylate). The insertion poly(methyl acrylate) and the crosslinked insertion poly(methyl methacrylate) and dilute-solution properties quite different from conventional polymers of these monomers, the differences including high light-scattering molecular weights combined with low viscosities, low values of the second virial coefficient, unusually large variations of the Huggins' constant k′ with the time-temperature history of the solutions, and low sedimentation velocities. These properties suggest that the insertion polymers have compact structures and are consistent with the postulate of sheetlike macromolecules. The dilute-solution properties of insertion poly(methyl methacrylate) made without crosslinker, unlike those of similarly prepared poly(methyl acrylate), were similar to those of conventional poly(methyl methacrylate). This difference in behavior is attributed to the different tendencies of the two monomers to undergo branching or crosslinking during radical polymerization.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1966.160040315
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    Paper (German National Licenses)
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