Seeded emulsion polymerization of butylacrylate: “Zero‐one or pseudo‐bulk?”

Abstract

The kinetics of the emulsion polymerization of butyl acrylate at 20 "C in Smith-Ewart interval 111 were investigated using a redox initiator system peroxodisulfatebisulfite-copper. The aim of this work was to obtain more basic knowledge about the kinetic behavior of the butyl acrylate system. Monomer conversion into polymer was based on gravimetrically calibrated online densitometry. The experimentally obtained conversion versus time curves for these seeded reactions were fitted by a linear regression procedure (slope and intercept) as well as by a nonlinear regression procedure based upon zero-one kinetics. The conclusion is that the emulsion polymerization of butyl acrylate may reflect zero-one kinetics up to a particle size of approximately 130 nm. The rate coefficients for entry and exit can be obtained fairly accurately with the slope and intercept procedure and with the nonlinear regression method if the propagation rate coefficient is accurately known. However, this is not the case. Therefore the development of universal procedures for obtaining the propagation rate coefficients is essential, since this parameter is of paramount importance in all further model calculations concerning emulsion polymerization.x exp [-20 f 2 x 1 O~/ R T ] (40 "C --7 0~x 2 ) k = 107.4*0.4 P Acta Polymer., 47,441-449 (1996) 0 VCH Verlagsgesellschafi mbH, D-69451 Weinheim, 1996

Emulsion and miniemulsion polymerizations with an oil‐soluble initiator in the presence and absence of an aqueous‐phase radical scavenger

“…The k p value calculated by this equation is 4198 L mol −1 s −1 for 40 °C, at least an order of magnitude higher than the value used by most researchers. With this value, the system appears to be 0–1 rather than pseudobulk, as shown by Zirkzee et al25 Beuermann et al26 and Lyons et al27 measured k p for BA by PLP analysis. Their data have been fitted as k p = 1.8 × 10 7 exp(−17,400/ RT ).…”

Semibatch emulsion polymerization of butyl acrylate. I. Effect of monomer distribution

“…The average radical number can be simply obtained from the overall rate of reaction as where k p is the propagation rate constant, and N a , Avagadro's number. It has been shown before that, for BA, k p values reported in the literature are very spread out 14, 15. Taking k p = 4900 L mol −1 sec −1 at 50°C,14 the steady‐state radical number, n ss , is calculated and shown in Table IV for most sets.…”

Unseeded semibatch emulsion polymerization of butyl acrylate: Bimodal particle size distribution

“…28 For BA emulsion polymerization, the exit rate was reported to be appreciable so that particles contained one or zero radicals from early in the reaction. 21,24 Monomodal PSDs were observed for a few latexes examined from the batch experiment series reported previously. 21 Thus, the occurrence of bimodal PSDs in BA semibatch emulsion polymerizations can be attributed to the secondary nucleation brought about by addition of monomer emulsion feed.…”