Experimental and Mechanistic Modeling Study of Self-Initiated High-Temperature Polymerization of Ethyl Acrylate

High-temperature polymerization of acrylates involves numerous reactions. A reliable quantitative understanding of these reactions allows for producing high quality polymers and for reliably designing, optimally operating, and intensifying the processes that produce the polymers. This paper presents an experimental and theoretical study of self-initiated thermal bulk polymerization of ethyl acrylate (EA) at 140, 160, 180, 200, and 220 degrees C. It reports kinetic parameter values for five important reactions of high-temperature EA homopolymerization. Before this study, only rate coefficients for secondary-radical propagation had been reported for EA. Guided by the family type behavior of acrylates, chain transfer to monomer from secondary and tertiary radicals, beta-scission, backbiting, and monomer self-initiation reaction rate coefficients were estimated from measurements of monomer conversion and polymer average molecular weights. The resulting mechanistic model was found to predict monomer conversion and polymer average molecular weights satisfactorily over the wide temperature range. The estimated values of the EA self-initiation and chain transfer to monomer reaction rate coefficients are in good agreement with those predicted by computational quantum chemistry.