Modeling and experimental studies of emulsion copolymerization systems. I. Experimental results

Abstract

A systematic experimental and modeling study of several emulsion copolymerization systems has been performed, and will be reported in a series of papers. Ten binary and three ternary copolymerizations involving styrene, methyl methacrylate, butyl acrylate, butadiene, vinyl acetate, acrylic acid, and ethylene were studied varying polymerization temperature, monomer composition, water to monomer ratio, initiator and emulsifier concentrations. Conversion, particle size, copolymer composition, and gel content were measured at several reaction times. The goal of this series of papers is to assess our quantitative understanding of emulsion copolymerization expressed in the form of a comprehensive mathematical model applied to monomers widely used in industry. In this first paper of the series, a global comparison of the experimental results is made. It is observed that the gel content is higher in systems containing butyl acrylate and butadiene, and smaller in systems containing methyl methacrylate. Larger particle numbers are obtained for lattices containing acrylic acid and butadiene. It is also shown that, for most of the systems, integration of the simple Mayo–Lewis equation is adequate to explain the drift in copolymer composition observed experimentally. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2360–2379, 2001

Modification research on the peel strength of the acrylate emulsion pressure‐sensitive adhesives

“…As we know, when a BA-rich monomer mixture is polymerized in the absence of a crosslinker, a gel is formed by a chain-transfer mechanism, and it involves two steps: (1) branch radical formation via either intramolecular chain transfer by back-biting or intermolecular chain transfer to polymer due to the presence of labile hydrogen in the BA unit of the polymer chains [19][20][21] and (2) gel formation through combination termination between the branched polymer radicals. The result was consistent with the work of Araujo et al, 23 24 For the latex prepared with St, the gel content was lower than that of its MMA counterpart. The result was consistent with the work of Araujo et al, 23 24 For the latex prepared with St, the gel content was lower than that of its MMA counterpart.…”

The Effect of Chain Transfer Agent Level on Adhesive Performance and Peel Master‐Curves for Acrylic Pressure Sensitive Adhesives

“…[19] In addition, the inclusion of MMA in acrylate copolymerisations has been shown to reduce the levels of branching [20] and to reduce the level of gel. [21] We suggest that the data presented in Table 1 show that increasing the level of copolymerised EHA results in higher gel contents through higher levels of intermolecular chain transfer to polymer as a result of an overall increase in the tendency for chain transfer to polymer. In addition, we suggest that the gel contents presented in Table 1 also reflect the competing influence of MMA where the increasing level of copolymerised MMA serves to moderate the tendency for chain branching and gel formation as a result of the increasing EHA level.…”

Reactivity ratios and monomer partitioning in the microemulsion copolymerization of vinyl acetate and butyl acrylate

“…A material balance for monomer 1 yields the following equation17: with f 1 = f 10 at X = 0. Deriving eq.…”