Solvent effects in butyl acrylate and vinyl acetate homopolymerizations in toluene

Abstract

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.

Skin Development during the Film Formation of Waterborne Acrylic Pressure-Sensitive Adhesives Containing Tackifying Resin

“…There have been a few studies of waterborne PSA film formation, [25] but there is scarce knowledge of the film formation of waterborne tackifiers, even though problems with adhesive performance have been blamed on this lack of understanding.…”

“…The present work was motivated by this knowledge gap and by an appreciation of the importance of film formation in determining waterborne PSA properties. [25] In our previous research, [33] we found with magnetic resonance (MR) profiling that during the drying of an acrylic waterborne PSA film, a water concentration gradient develops. There was less water near the interface with the atmosphere, however the water level never receded from this interface.…”

“…[25] Generally it has been found that the performance of waterborne acrylic PSAs is inferior to that of their solvent-based analogues. They exhibit lower water resistance, [26] a tendency to whiten in moist atmospheres, and lower tack, adhesion and shear strengths.…”

Probing particle structure in waterborne pressure-sensitive adhesives with atomic force microscopy

“…[4] Generally, it has been found that the performance of waterborne acrylic PSAs is inferior to that of their solvent-based counterparts. They exhibit lower water resistance, [5,6] a tendency to whiten in moist atmospheres, and lower tack, adhesion and shear strengths.…”

Simultaneous free radical and addition miniemulsion polymerization: Effect of the diol on the microstructure of polyurethane-acrylic pressure-sensitive adhesives

“…After this period, the box was taken out from the solvent and drained in the dessicator for another hour. The humidified box and swollen gel were weighed (weight=W 3 ) and dried in a ventilated oven at 60 ºC overnight. Finally, the dried box and gel polymer were again weighed (weight=W 4 ).…”