Estimation of Free Radical Polymerization Rate Coefficients Using Computational Chemistry

This study explores the application of computational chemistry to estimate free radical polymerization rate coefficients. The Evans-Polanyi relationship is combined with computed heats of polymerization to estimate copolymerization reactivity ratios for many vinyl monomer pairs, focusing on acrylates, methacrylates and styrene, with accuracy assessed by comparison to experimental values. The effect of different optimization approaches on the values of thermodynamic properties is explored, and it is concluded that a combination of conventional optimization and relaxed potential energy scans was most effective at identifying global minima. The difference between thermodynamic properties calculated using the harmonic oscillator treatment and a hindered rotor model is evaluated for methyl methacrylate polymerization.