Particle Formation in Vinyl Chloride Emulsion Polymerization. Experimental Study

Abstract

Particle formation in vinyl chloride emulsion polymerization has been investigated by means of ab initio and seeded experiments. A series of ab initio polymerizations was run in order to obtain reliable data regarding the dependence of the particle number on the emulsifier (SDS and SDBS) concentration, as well as to analyze the effect of the initiator concentration, stirring rate, and monomer-to-water ratio upon the particle number and the polymerization kinetics. Seeded polymerizations carried out at different concentrations of seed latex and surfactant made it possible to quantitatively evaluate the influence of these factors on the onset and extent of secondary particle formation.

Particle Formation in Vinyl Chloride Emulsion Polymerization: Reaction Modeling

“…6 We begin by addressing the modeling of particle growth by polymerization and then focus on the more-intricate subjects of particle formation and particle size distribution.…”

“…In contrast, to obtain good agreement in runs A21, A20, A17, and A19, the value of fk d given in Table 4 must be multiplied by a factor of 1.5. This change in the kinetics seems to be correlated with the transition observed in the N- [SDS] curve that was identified in the experimental part: 6 the first and the second set of experiments correspond, respectively, to the parts of the curve before and after the sudden increase in particle number. To explain this observation, one could invoke an effect of [SDS] on the rate of initiation and, indeed, the factor of 1.5 is consistent with the dependence of fk d on [SDS] that was measured by Neelsen et al 68 However, note that the latter authors found a continuous increase of fk d with [SDS], whereas our results suggest an abrupt variation of fk d .…”

“…1,2 The objective of the present work is to contribute to the development of this type of mechanistic model of emulsion polymerization and, more particularly, to the modeling of particle formation and particle size distribution (PSD) in the emulsion polymerization of vinyl chloride (VCM). Experimental results on the kinetics of polymerization and particle formation have been reported in a previous publication (see the first part of this series of papers 6 ). Here, we will focus on the modeling of this system.…”

“…The result, depicted in Figure 9, is a plausible PSD with a value of N within the range of those typically observed in this system (see, e.g., Figures 3 and 4 in the first part of this series of papers 6 ).…”

Role of electrolytes in the preparation of nanoparticles via the emulsion polymerization of vinyl pivalate

“…To obtain diameter sizes below 0.1 lm, it is necessary to use a large amount of surfactant in the polymerization system [1][2][3]. Most experiments regarding emulsion and miniemulsion polymerizations use the surfactants to study the growth mechanism.…”