A comprehensive investigation into "controlled/living" chain growth crosslinking copolymerization including a back to basics modeling
2009
Poly, Julien | Wilson, DJames | Destarac, Mathias | Taton, Daniel
The mainstay of this description is a modeling of "controlled/living" chain growth crosslinking copolymerization (C/L CC) that is based on a simple equivalent kinetic scheme, resulting from assumptions consistent with an ideal C/L behavior. Analytical expressions of the double bond concentration according to reaction parameters are derived from the corresponding set of differential equations, and consideration of the respective values of the rate constants enables one to forecast the morphology of the branched polymers derived by C/L CC. The kinetic scheme is then enriched with a necessary distinction between intramolecular (cyclization) and intermolecular crosslinking which contribute to the formation of three-dimensional structures and to the increase of molar masses, respectively. This consideration leads to a key-equation governing C/L CC, which can be exploited in two ways. Its implicit integration coupled with a semi-empiric methodology gives an easy access to all the characteristic magnitudes of the products at complete conversion of the double bonds. An alternative approach implying a supplementary modeling of local concentration effects enables its numerical resolution. Modeled trends and predicted characteristic values are then successfully compared with experimental data which relate to xanthate-mediated radical CC. Specific reasons of dispersity related to the mechanism of CC are also discussed.
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