Date of Award

12-1987

Degree Name

Doctor of Philosophy

Department

Chemistry

First Advisor

Dr. George G. Lowry

Second Advisor

Dr. James A. Howell

Third Advisor

Dr. H. D. Warren

Fourth Advisor

Dr. Robert E. Harmon

Abstract

The goal of this study is to present a method that gives higher conversions and molecular weights for the polymerization of vinyl benzoate than obtained in previous investigations.

Polyvinyl benzoate has benzene rings attached to the backbone chain, therefore is hard and rigid. This is a characteristic which has a large application area. However previous studies in polymerizing vinyl benzoate with bulk and solution polymerizations reported low yields and troublesome crosslinking, which has limited its application. Emulsion polymerization method has the advantage of giving high polymerization rates together with high molecular weights, and therefore was chosen as the method for polymerization for vinyl benzoate in this study.

For the most suitable laboratory synthesis of vinyl benzoate, the vinyl interchange reaction between vinyl acetate and benzoic acid was used.

In emulsion polymerizations, emulsifiers and initiators have important effects on polymerization rates and molecular weights. Therefore different emulsifier and initiator systems were tried to find an emulsion polymerization recipe that would give high conversions and high molecular weights. These efforts were successful and a recipe that gives 95% conversions in two hours at 75$\sp\circ$C is reported. However molecular weights were somewhat low and further research in studies of recipes with a decrease in the amount of chain transfer agent is suggested.

The rate studies of the emulsion polymerization of vinyl benzoate revealed that increasing the initiator concentration increased the rate as expected. However there was an uncertainty in the increase of rate with increasing emulsifier concentration. Therefore for a better understanding of the polymerization behavior of vinyl benzoate, a more detailed study is recommended to determine the relationship of the number of free radicals in the polymer particle and the functionality of the particle number, N, to the initiator and emulsifier concentrations.

To aid the studies in the physical applications of polyvinyl benzoate, its absorption spectra, refractive index increments, viscosity average molecular weights for different recipes, its cohesive energy density and its film forming characteristics are also reported.

Access Setting

Dissertation-Open Access

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