The apparent rate constant model for kinetics of radical chain copolymerization: Chemical‐controlled process

Abstract

In this article the kinetics of chemical-controlled radicalchain copolymerization have been reduced to pseudohomopolymerization kinetics by introducing the apparent rate constants. The methods for the determinations of the values of the apparent rate constants, mode oftermination, and the methods for the calculation of molecular weights and distributions are proposed. The data required for these determinations and calculations are simply obtained by the usual steady-state method. According to the traditional kinetics along with the definitions of the apparent rate constants, these apparent rate constants as functions of traditional rate constants, monomer compositions, and copolymer compositions are derived. Further utilizing the theoretical expressions obtained, we show that the apparent rate constants are the general rate constants for both radical chain homo-and copolymerizations. The bulk radical copolymerizations of methyl methacrylate and styrene at various monomer feed compositions at 60°C are used to test the proposed model. The empirical apparent rate constants obtained are described well, by the following expressions, l/k," = -0.132 X IO-'(FIlf) + 0.428 X lo-' (Fdf) and kp/(k,")' = -0.138 x 104(F,/jl)2 + 0.354 X 104(F1F2/fif2) -0.114 X 104(F2/f)'and the mode oftermination based on the combination termination is p = 0.997 F l + 0.398 Fz + 0.039 (FIF,)) where k," and k? denote the apparent rate constants of propagation and termination, respectively. The termfi(= 1 -f2) stands for the mole &action of sytrene in the monomer soldtion fed. F, is the copolymer composition produced atfl. p is the mode of termination.

Modeling and experimental studies of aqueous suspension polymerization processes. 1. Modeling and simulations

“…The apparent rate constants are then used to model the copolymerization as a pseudo-homopolymerization system. Detailed examples of this approach are available in the literature (Hamielec and MacGregor, 1983; Kuo and Chen, 1981; Kuo et al, 1984).…”

Modeling of imperfect mixing and its effects on polymer properties

“…The copolymerization systems are modeled with a pseudohomopolymerization approach based on the instantaneous property method (Hamielec and MacGregor, 1983;Kuo et al, 1984). A set of apparent rate constants is calculated from the instantaneous monomer and copolymer properties.…”

Scale-Up Studies on Styrene−Butyl Methacrylate Copolymerization Reaction

“…The relative ease of copolymerization of styrene with butyl methacrylate has made the latter the most favoured monomer when compared to other methacrylates and acrylates to be used with the former monomer. Copolymerizations of styrene with methyl acrylate, methyl methacrylate, − butyl acrylate, , and acrylonitrile , have been studied in both emulsion and suspension modes. The effect of reaction conditions on the rate of the copolymerization reaction has been thoroughly examined.…”