Experimental Study of a Tetrafunctional Peroxide Initiator: Bulk Free Radical Polymerization of Butyl Acrylate and Vinyl Acetate

Abstract

This investigation examines the use of a tetrafunctional peroxide initiator in the bulk free radical homopolymerization of butyl acrylate and vinyl acetate. Rate of polymerization, molecular weights and in certain cases, gel fraction data were collected for selective experiments and compared to the results obtained with a monofunctional counterpart. In order to avoid the formation of insoluble gel material, further experiments were completed with varying concentrations of a chain transfer agent. Experimental results showed that when used at identical concentrations, the tetrafunctional initiator produced a faster rate in the polymerization of both butyl acrylate and vinyl acetate compared to the monofunctional initiator. Without the use of a chain transfer agent, runs with butyl acrylate produced significant amounts of gel material isolated by Soxhlet extraction. For a particular reaction time, the tetrafunctional initiator produced higher levels of gel compared to its monofunctional counterpart. When a chain transfer agent was used, the molecular weights were determined by its concentration and in turn, initiator functionality did not have an impact. In the polymerization of vinyl acetate, similar observations were made and no discernable difference could be seen between the molecular weight results of samples produced with either initiator.