Mathematical model for the bulk polymerization of styrene using the symmetrical cyclic trifunctional initiator diethyl ketone triperoxide. I. Chemical initiation by sequential decomposition

Abstract

In this study, we experimentally and theoretically investigated the use of the symmetrical cyclic trifunctional initiator diethyl ketone triperoxide (DEKTP) in the bulk polymerization of styrene. The experimental study consisted of a series of isothermal batch polymerizations at different temperatures (120 and 130 C) with different initiator concentrations (0.005, 0.01, and 0.02 mol/L). A mathematical model was developed to predict the evolution of the reacting chemical species and the produced molecular weight distributions. The kinetic model included chemical and thermal initiation, propagation, transfer to the monomer, termination by combination, and reinitiation reactions. The simulation results predict the concentration of diradicals, monoradicals, and polymeric chains, characterized by the number of undecomposed peroxide groups. The experimental results showed that at reaction temperatures of 120-130 C, initiation by DEKTP produced an increase in the polymerization rates (R p 's) and average molecular weights, depending on the initiator concentration, due to sequential decomposition. The mathematical model was adjusted and validated with the experimental data. The theoretical predictions were in very good agreement with the experimental results. Also, an optimum initiator concentration was observed that achieved high R p 's and high molecular weights simultaneously. For polymerization temperatures of 120-130 C, the optimum concentration was 0.01 mol/L.

Solution styrene polymerizations performed with multifunctional initiators

“…[1][2][3][4][5][6][7] However, application of multifunctional initiators is predominantly performed in styrene polymerizations, mainly in bulk and solution processes. 1,[8][9][10][11][12][13][14][15] Multifunctional initiators can be defined generically as chemical compounds that contain more than one unstable chemical function (normally azo or peroxide) and therefore can generate more than two free radicals when they decompose (usually thermally). The number of radicals generated and the rate of decomposition can depend on the reaction stage, operation conditions, and chemical properties of the unstable groups.…”

“…Since the late 1980's, several studies have been published regarding the use of multifunctional initiators in different polymerization processes, including characterization and applications of the obtained polymer materials and the mathematical modeling of the reaction system, although the vast majority of these studies has been focused on the PS production. [8][9][10][11][12][13][14][15] Since the beginning of the 21 st century, experimental and modeling studies related to the use of multifunctional initiators (bi, tri, and tetrafunctional molecules) in polymerization processes have been extended to other styrene, 8,[12][13][14][27][28][29] methyl methacrylate (MMA), 5,6,30 vinyl V C 2015 Wiley Periodicals, Inc. chloride, 31,32 vinyl acetate, 7,33 and styrene/MMA copolymerization systems. 6,34 Despite that, it seems correct to say that the commercial use of multifunctional initiators in free radicals polymerization reactions is related primarily to styrene bulk polymerization reactions.…”

Experimental and theoretical study of the use of multifunctional initiators in the high impact polystyrene bulk process

“…The medium cis ‐PB was provided by Dynastol Elastómeros S.A de C.V., México ( ). Cyclic initiators DEKTP and PDP were synthesized and characterized as in our previous work .…”

Mathematical modeling of molecular weight distribution in miniemulsion polymerization with oil‐soluble initiator

“…Hence the solution of the MWD is usually a challenging task and several numerical methods have been proposed for this purpose in the literature over the last four decades, including the method of moments associated with a distribution, for example, Schultz-Flory, 5,6 Pearson-type I, 7 or log-normal 8 distribution; Monte Carlo simulation; [9][10][11] probability generating functions; 12 numerical fractionation; 13,14 orthogonal collocation technique; [15][16][17] and direct numerical integration method. [18][19][20][21][22][23] Besides providing the MWD directly (with no need of function inversion), direct numerical integration method also reduces the loss of information during the solution step. The use of this method for MWD of free-radical polymerization was first proposed by Chaimberg and Cohen in 1990, 19 together with the use of continuous variable approximation (CVA) and quasi-steady state assumption (QSSA) for the radicals.…”