Relative reactivities in vinyl copolymerization

Abstract

From data in the literature on relative rates of copolymerization it has been possible to evaluate two constants, Q and e, characteristic of an individual monomer, which appear to account satisfactorily for its behavior in copolymerization. The constant Q describes the “general monomer reactivity” and is apparently related to possibilities for stabilization in a radical adduct. The constant e takes account of polar factors influencing copolymerization.

Copolymerization of ethylene and vinyl acetate at low pressure: Determination of the kinetics by sequential sampling

“…Equation (2-5) can be rearranged to: Except for the arrangements made in conneetion with the specific parameters arising from the experiments described in this thesis, equation (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) corresponds with integrated forms derived by other investigators (refs. 1, 11, 12, 13).…”

“…Combination with k 11 • P 1 Q 1 exp(-e 1 2 ) , where the assumption is made that the "charge" on the double bond of a monoroer equals that on the end group of the radical of the same monoroer, leads to: -20) and (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21) The product of reactivity ratios ~ • r 1 r 2 is an excellent measure of the alternation tendency in vinyl copolymeri- values of other monomars will repreaent the polarity on the double bond induced by a certain substituant. Q 0 only depends on r 2 = k 22 tk 21 and requires no adjustment owing to differences in double bond polarity.…”

“…8, 9) made the following assumptions (expressed in the nomenclature used here) for ethylene (a) -vinylacetate "head-to-tail" (b) -vinylacetate "head-to-head" ( c) : (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17) When m = 0 equation (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17) reduces to the conventional copolymerization equation. If penultimata effects occur or anomalous addition takes place, the P-values calculated from the conventional copolymerization equation should be dependent on the initial monomer feed composition.…”

Prediction of Monomer Reactivity in Radical Copolymerizations from Transition State Quantum Chemical Descriptors

“…For example, the assumption that permanent electric charges exist on all the species involved, including hydrocarbons, is very unlikely. Moreover, the assumption that the polarity of a monomer being identical to that of the corresponding radical derived from that monomer is under debate [1,[3][4][5] .…”

“…Alfrey and Price [4] assumed that the parameter Q may reflect the general reactivity of a monomer (or a radical), that is, the energetic property or the thermodynamic property, as it governs reactivity in all chemical processes. In addition, the parameter e may reflect the supposed permanent electric charge resulting in mutual attraction or repulsion between the two monomers (or radicals).…”