Propagation Rate Coefficient of Non‐ionized Methacrylic Acid Radical Polymerization in Aqueous Solution. The Effect of Monomer Conversion

Termination Kinetics of 1‐Vinylpyrrolidin‐2‐one Radical Polymerization in Aqueous Solution

“…In aqueous solution, k p varies with monomer concentration and thus also during the course of a polymerization to high conversion, where the ratio of monomer-to-water concentration changes. Consistent with what has been found for methacrylic acid, [12] recent investigations into aqueoussolution polymerization of 1-vinylpyrrolidin-2-one (VP) in the presence of different amounts of premixed poly-(1-vinylpyrrolidin-2-one) (poly(VP)), which mimics monomer conversion, revealed that it is the ratio of monomeric VP-to-water concentration which affects k p . [15] Implementing the k p data that is available for VP polymerizations at various initial monomer concentrations and up to different degrees of monomer-to-polymer conversion, k t may be derived via SP-PLP-NIR measurements on aqueous-solution VP polymerizations over an extended concentration and conversion range and up to high pressure.…”

“…It was recently shown, that k p depends on the monomer-to-water ratio, whereas the content of high-molecular-mass polymer plays no role. [12,15] The weight fraction of VP, w VP , during polymerization to high degrees of monomer conversion, X, is represented by Equation (2):…”

“…As mentioned by Beuermann et al, [12] polymer may affect k p only under conditions of very high polymer content or in case that polymer is of low molar mass and should be better referred to as oligomeric material. Combining Equation (1) and (2) with the volume of activation for propagation of VP, DV z (k p ) ¼ À11.3 cm 3 Á mol À1 , [28] yields k p for 40 8C as a function of pressure, p, initial weight fraction of VP, and monomer conversion:…”

Propagation Kinetics in Radical Polymerization Studied via Pulsed Laser Techniques

“…This insensitivity of (bulk polymerization) k p toward the degree of monomer conversion must not hold in solution polymerizations, as has been demonstrated for MAA polymerizations in aqueous solution, [11] where k p was observed to increase toward higher degrees of monomer conversion. This effect may also be adequately understood on the basis of the genuine kinetic argument that it is the friction experienced by the TS structure which controls A(k p ).…”

Solvent Influence on Propagation Kinetics in Radical Polymerizations Studied by Pulsed Laser Initiated Polymerizations

“…To study the influence of monomer conversion on k p , PLP-SEC was conducted on reaction mixtures containing different amounts of polymer from the preceding polymerization. [56,58] The experiments were carried out for methacrylic acid and N-vinyl pyrrolidone. The concentrations were chosen such that the reaction mixture mimics a polymerizing system initially containing 20 wt.-% of monomer.…”