Termination Kinetics of Methyl Acrylate and Dodecyl Acrylate Free-Radical Homopolymerizations up to High Pressure

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“…[38] The reactivity ratios were determined via 1 H NMR analysis of MA-DA copolymer samples to be r DA ¼ 0.70 and r MA ¼ 0.78 at 40 8C and 1 000 bar, [23] which yields as radical reactivity ratios: s MA ¼ s DA ¼ 0.74. [28] In order to reduce the number of experiments, these k t,copo (p,T ) studies have been performed only for a single monomer feed composition, f MA,0 ¼ 0.5. [23] Plotted in Figure 3 are the resulting homo-and copolymerization termination rate coefficients as a function of initial MA mole fraction for two sets of polymerization temperature and pressure conditions, 1 000 bar/40 8C and 10 bar/30 8C.…”

“…Several SP-PLP experiments may be carried out during the course of a polymerization reaction which yields the conversion dependence of k t /k p . [28] Due to the considerable fundamental and industrial interest in free-radical polymerization of systems with more than one monomer, both techniques, PLP-SEC and SP-PLP, have also been applied toward the measurement of copolymerization k p and k t (see for example ref. It is assumed that k p from PLP-SEC studies at low conversion holds up to high degrees of monomer conversion.…”

“…[24] The very simple mixing rule (Equation (4)) to be applicable requires (i) the same mechanism of termination being operative for both monomers, which seems to be the case in the plateau region of constant k t at low and moderate degrees of monomer conversion, and (ii) the concentration of radicals terminating in units i or j to be linearly related to the mole fraction f 1 . [28] Two sets of experiments were performed. It should be noted that the penultimate k t model in conjunction with the geometric mean approximation (Equation (3)) is also applicable toward estimates of cross-termination rate coefficients in acrylate-methacrylate copolymerization.…”

The RAFT Process as a Kinetic Tool: Accessing Fundamental Parameters of Free Radical Polymerization

“…Additionally, the RAFT-CLD-T method relies on accurate online determination of the polymerization rate, and given their rapid polymerization, acrylates are an attractive option for experimental validation of this procedure. Also, acrylates are used extensively in industry and complete characterization of their FRP kinetics would be advantageous as is evident from the numerous investigations of acrylate kinetics found in the literature [33,38,87,88,90,91,95,97,[119][120][121][122][123][124][125][126]. Thus, the impact of fast propagation, backbiting and midchain radical reactions on the method's ability to obtain accurately the chain length dependence of k t for both similar and disparate size radicals is investigated with the goal of aiding the experimentalist in choosing the optimum polymerization system for validating the recently introduced k s ,l t methodology.…”

Miscibility, viscosity and density of poly (ɛ-caprolactone) in acetone+CO2 binary fluid mixtures

“…Viscosity is an especially important parameter, which influences not only the rheological and flow or mixing behavior, but also the mass and heat transfer characteristics of these solutions. Viscosity is an important factor in polymerizations that influences chain termination reactions and thus reaction kinetics [3]. Perhaps a lesser-recognized additional factor is the influence of viscosity on the physical rate processes such as phase separation processes in polymer solutions [4].…”