Modeling poly(vinyl alcohol)‐stabilized vinyl acetate emulsion polymerization. II. Comparison with experiment

Abstract

SYNOPSISThe mathematical model presented in Part I, accommodating the emulsion polymerization of vinyl acetate stabilized with poly (vinyl alcohol), predicts experimental conversion and particle size data with reasonable accuracy. Model predictions of measurable variables exhibit sensitivity to variables affecting either primary ungrafted particle nucleation or flocculation kinetics, but are relatively insensitive to variables affectingpoly (vinyl alcohol) grafting reactions and the resulting primary grafted particle concentration. Semibatch simulations indicate that independent increases in the vinyl acetate, poly(viny1 alcohol), and initiator levels all increase the primary grafted particle population. It is unlikely, however, that this population exceeds the ungrafted counterpart under most commercial polymerization conditions. This relative insignificance of grafting during particle nucleation is also noted in literature data simulations where, with appropriate parameter adjustments, the model predictions agree well with the batch, thermal initiation data. 0 1993 John Wiley & Sons, Inc.

Modelling the semi-batch vinyl acetate emulsion polymerization in a real-life industrial reactor

“…The 7-m 3 reactor is continuously stirred. The use of a polymeric emulsifier affects the kinetics of the reaction and the mechanism of stabilization of the particles [20,21]. It also increases the rate of thermal decomposition [23,24].…”

“…As the objective of this model was to show the influence of the polymerizable surfactant, other aspects, such as the balance of the number of particles, were modelled less rigorously. Gilmore et al [20,21] presented, in 1993, the first model in which grafting onto the polyvinyl alcohol backbone during nucleation was considered. Arau´jo and Giudici [22] developed a model intended for optimization, considering a non-polymerizable emulsifier.…”

Poly(vinyl acetate‐co‐dibutyl maleate) latex films in the presence of grafted and post‐added poly(vinyl alcohol)

“…They concluded that the presence of a large monomer/H 2 O interface area is essential for PVOH grafting to create a PVOH‐stabilized acrylic latex. Gilmore et al7, 8 used mathematical modeling to explore the kinetics of VAc emulsion polymerization in the presence of PVOH. They inferred that grafting in the nucleation stage is not very important.…”

Semicontinuous emulsion polymerization of vinyl acetate: Effect of ethoxylation degree of nonionic emulsifiers

“…Polymer films obtained from the latices prepared in the presence of poly(vinyl alcohol) re-sulted in higher tensile strengths than of those prepared with only nonylphenol ethoxylates, presumably due to the formation of a reinforcing poly(vinyl alcohol) structure. 22 Gilmore et al modeled poly(vinyl alcohol)-stabilized semicontinuous VAc emulsion polymerization 23 and compared their model with experimental findings. Their model suggests that, when the molar ratio of VAc to poly(vinyl alcohol) is high, physical adsorption of poly(vinyl alcohol) onto the latex particle is a more important process than is grafting.…”

“…Their model suggests that, when the molar ratio of VAc to poly(vinyl alcohol) is high, physical adsorption of poly(vinyl alcohol) onto the latex particle is a more important process than is grafting. 23 In our work, the effect of the ethoxylation degree of ethoxylated nonylphenol nonionic emulsifiers in the semicontinuous emulsion polymerization of the VAc monomer in the presence of 88% of a hydrolyzed poly(vinyl alcohol) colloid stabilizer was examined to determine the effect to the final latex viscosity, average polymer molecular weight, polymer grafting degree, latex surface tension, and surface free energy of the dried films.…”