Evaluation of individual rate constants from the chain-length distribution of polymer samples prepared by intermittent (rotating sector) photopolymerization—2. The copolymerization system styrene-methyl methacrylate

Kinetics of the Aqueous-Phase Copolymerization of MAA and PEGMA Macromonomer: Influence of Monomer Concentration and Side Chain Length of PEGMA

“…There is considerable experimental evidence [37][38][39] showing that, in many copolymerization systems, propagation depends on the nature of the monomer and on the last two units of the growing chain. This is referred to as penultimate model.…”

Solvent Effects on the Rate Constant of Chain Propagation in Free Radical Polymerization

“…This system should be expected to behave rather like pure styrene for two reasons: ®rstly, the average k p in this system is very similar to that observed in pure styrene [17]; secondly, this copolymerization system is nearly an azeotropic one leading to a copolymer which has a composition very close to the composition of the comonomer system (1:1). Because k p for radicals ending in methyl methacrylate units is nearly four times that for radicals ending in styrene units, the overall population of radicals is governed by the latter ones (75±85%, depending on the model applied) [17].…”

“…Because k p for radicals ending in methyl methacrylate units is nearly four times that for radicals ending in styrene units, the overall population of radicals is governed by the latter ones (75±85%, depending on the model applied) [17]. This expectation is also widely re¯ected in the k p data observed: toluene, anisole, methyl isobutyrate, bromobenzene, benzene, mesitylene, and 1,2-dichloroethane as solvents are of negligible in¯uence on k p , whereas slightly increased k p values (somehow in contradiction to the results obtained for styrene polymerization) are observed for acetonitrile and dimethyl formamide as solvents.…”

“…Eight standards with narrow molecular weight distribution (polystyrene and poly(methyl methacrylate), respectively) were used for the construction of the calibration curves for the analysis of polystyrene and poly-(methyl methacrylate) samples; for the poly-co(styrene-methyl methacrylate), a calibration curve was calculated based on a linear combination of the calibration curves for polystyrene and poly(methyl methacrylate) as in Ref. [17]. The molecular weight distribution curves were ®nally analysed for their points of in¯ection by numeric differentiation and looking for the position of the maximum of the ®rst derivative.…”

Photopolymerization: A Review

“…The copolymerization of styrene-diethylfumarate photoinitiated by benzil [42] was studied at 25 C and 60 C. Copolymer compositions were obtained using 13 C-NMR. Individual rate constants have been evaluated [43] from the chain-length distribution of polymer samples of styrene-co-MMA prepared by intermittent photopolymerization. Individual rate constants have been evaluated [43] from the chain-length distribution of polymer samples of styrene-co-MMA prepared by intermittent photopolymerization.…”