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  • 1
    Electronic Resource
    Electronic Resource
    Calculations on the Polymerization Process of Some 1,1-Disubstituted Cyclopropanes: I. The Initiation Step (1998)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1998 (1998), S. 1397-1402 
    Details
    ISSN: 1434-193X
    Keywords: Polymerization process ; Ab initio calculations ; 1,1-Disubstituted cyclopropanes ; Polymerization enthalpies ; Transition state ; Energy barriers ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ab initio calculations on the initial steps of the polymerization process of 1,1-dicyano-, -difluoro- and -di-methyl-substituted cyclopropanes are presented. Polyme-rization enthalpies determined by model calculations show the thermodynamic feasibility of the process. The reaction mechanism of the first step is further discussed by considering initiation by various species such as Hq, OHq, and CH3q (q = +, 0, -). Transition structures and energy barriers are obtained for all species, allowing discussion of the reaction mechanism and an estimation of the kinetic feasibility. The Hartree-Fock structures at the 6-31+G(d, p) level have been fully optimized and electron correlation has been introduced at the MP2 level for some selected reaction mechanisms.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    A theoretical approach to the thermochemistry of the polymerization of some derivatives of the monomers CH2=X (X = CH2, NH, O) (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Theory and Simulations 6 (1997), S. 729-739 
    Details
    ISSN: 1022-1344
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In this work, we have calculated the thermodynamic parameters of the polymerization of some derivatives of the species CH2=X (X = CH2, NH, O), using ab initio methods of quantum chemistry and the usual formalism of statistical thermodynamics. It is shown that the Gibbs functions ΔGp°(l, c) corresponding to CH2=NOCH3, CNCH=NCN, CF2=O and all the percyano derivatives are largely positive which indicates that the spontaneous (radical or ionic) chain polymerization of these monomers is thermodynamically prohibited.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mats.1997.040060404
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  • 3
    Electronic Resource
    Electronic Resource
    A theoretical approach to the thermochemistry of radical and anionic polymerizations of various unsaturated monomers (1996)
    Weinheim : Wiley-Blackwell
    Macromolecular Theory and Simulations 5 (1996), S. 269-289 
    Details
    ISSN: 1022-1344
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In this work, we have calculated the thermodynamic parameters of the first steps of the free radical and anionic polymerizations of various unsaturated monomers, using ab initio methods of quantum chemistry. The enthalpies and entropies of polymerization were estimated assuming that they correspond to those of the model reaction A = B(p) + HABAH(p′) → HABABAH(p′) where p and p′ stand for the physical state of the considered species. The enthalpies of polymerization were rationalized using the equation ΔH0p = -ΔΣ NABEAB + SE(A = B) + SE(HABAH) - SE(HABABAH) where NAB is the number of A — B bonds, EAB the corresponding bond energy, - ΔΣ NABEAB the variation of the sum of the bond energy terms, and SE(X) the thermodynamic stabilization energy of compound X. The preferential mode of polymerization of each monomer was derived from the enthalpies of the initiation and initial propagation steps of the two types of polymerization. Thus, we were able to make some comments concerning the feasibility of the polymerization of the monomers under consideration.
    Additional Material: 12 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mats.1996.040050208
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