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A series of butyl acrylate (BA) and vinyl acetate (VAc) homopolymerizations in toluene was conducted to investigate the effect of solvent at different solvent and chain transfer agent (CTA) concentrations. Because the experimental determination of the individual propagation and termination rate constants for these systems is challenging, experimental observations were limited to the lumped rate constant (k p /k t 0.5 ). Differences in the lumped rate constant, at different solvent and CTA concentrations, were assumed to be attributed to the effect of solvent on the termination rate constant. Our hypothesis was that the termination rate constant k t was affected by the presence of solvent. At higher solvent concentrations, chain transfer to solvent occurs more frequently and leads to the formation of shorter chains, which move more easily and are able to terminate more quickly compared to longer chains. Thus, k t will increase, leading to a decrease in the lumped rate constant. The experimental results confirmed the presence of a solvent effect on the lumped rate constant. This effect was more pronounced in the case of VAc compared to BA solution homopolymerizations. Under the investigated conditions, increased CTA concentrations did not substantially affect the rate of BA homopolymerizations, whereas a slight synergistic effect between the CTA and solvent at higher CTA and solvent concentrations was apparent for VAc homopolymerizations.

In this study, butyl acrylate/methyl methacrylate (BA/MMA) latexes of bimodal molecular weight and particle size distribution were prepared in a multi‐step process by seeded conventional emulsion and seeded miniemulsion polymerization. For the conventional emulsion case, a BA/MMA batch copolymerization was conducted as a first step (seed generation) and was followed by a monomer addition step to ensure particle growth. In a third step, a BA/MMA pre‐emulsified mixture was added to generate a second particle population. For the miniemulsion case, a BA/MMA copolymerization was carried out as a first step (seed generation) and was followed by a monomer addition step. The addition of a BA/MMA miniemulsion served to generate a bimodal particle size and molecular weight distribution. The final latexes were coated onto a polyethylene terephthalate carrier, dried and their performance as pressure‐sensitive adhesives was evaluated using tack, peel and shear adhesion measurements. Structure‐property relationships between the adhesive properties and the weight‐average molecular weight and average particle size were examined. Even though the polymers obtained by miniemulsion showed better shear resistance, their shear resistance was low. There was no statistically significant difference in peel resistance of the polymers obtained by the two reactions. While a significant difference in tackiness between the two emulsion procedures was found when the adhesives were tested using the less sensitive, rolling ball test, no differences were found when they were tested using a loop tack test.

A study of butyl acrylate (BA) and vinyl acetate (VAc) solution homopolymerization and copolymerization in toluene was carried out. The conversion and copolymer composition were monitored using traditional techniques (gravimetry and 1 H-NMR spectroscopy) and attenuated total reflectance-Fourier transform IR (ATR-FTIR) spectroscopy with a diamond-composite probe and light conduit technology. The peak height of the characteristic absorbances of the monomer(s) during the course of the reaction was used to calculate the conversion and copolymer composition for the ATR-FTIR monitoring. The data obtained using a ReactIR™ 1000 reaction analysis system in the off-line mode showed very good agreement with data obtained using traditional techniques. The solvent effects on BA and VAc solution homopolymerizations and copolymerizations in toluene were also investigated. Improvement to model predictions was obtained by allowing the lumped constant (k p /k t 0.5 ) to vary with the solvent concentration. Experimental data and model predictions of the number-and weight-average molecular weights for the investigated systems are also presented.

Emulsion-based pressure-sensitive adhesives (PSAs) are gaining in importance due to their improved performance as well as the lower environmental impact of the emulsion polymerization process. In this study, the influence of eight emulsion polymerization variables on the final PSA properties of butyl acrylate/vinyl acetate (BA/VAc) emulsion-based PSAs was investigated (i.e., BA/VAc ratio, acrylic acid content, type and concentration of stabilizer, concentration of initiator, concentration of CTA, temperature, solids content). Final performance properties such as peel strength, shear strength, and tack were investigated on two different substrates: stainless steel and high-density polyethylene. A wide range of properties was generated ranging from very good to poor PSA performance. The screening design fulfilled its purpose in that it was used to generate a wide range of final properties. The results obtained here will be used in the decisionmaking process for further experimentation. However, for several reasons, the development of empirical models to relate the process conditions to the final product properties was not possible. In all three adhesive tests, the performance of the investigated adhesives was superior on the stainless steel substrate compared to high-density polyethylene. Most of the adhesives showed relatively high loop tack coupled with either adhesive or cohesive failure on both substrates. In most cases, peel strength was higher on stainless steel. A broad range of shear strength responses was observed: extremely high, on the order of several weeks, to zero shear strength. The chain transfer agent, which regulated the gel content of the emulsion latexes and the molecular weight of the soluble polymer fraction as well as the monomer feed composition, was suspected to be among the most influential factors affecting the final PSA performance. In addition, it was possible to obtain balanced final properties using either sodium dodecyl sulfate or poly(vinyl alcohol) as surfactant but at different concentrations.