Kinetic Study of the Free Radical Copolymerization of Methyl Methacrylate with 2-Perfluorooctyl Ethyl Methacrylate by Quantum Computational Approach

Abstract

Fluorinated copolymers with perfluoroalkyl side chains have widespread use in applicationsrequiring superior technology due to their unique surfacial properties. Kinetic analysis of copolymerization offluorinated acrylates with conventional acrylates is necessary to synthesize such copolymers efficiently.However, kinetic investigation of such reactions are limited in the literature due to the experimentaldifficulties. In this study, the kinetics of copolymerization of methyl methacrylate with 2-perfluorooctyl ethylmethacrylate in toluene medium using AIBN initiator was investigated using quantum chemistry postulates asan alternative to experimental methods. Reaction rate constants (kp) for propagation were determined usingtransition state theory. A terminal effect models were used to examine four different addition reactionsinvolving monomeric and dimeric radicals and monomers for both self- and cross-propagation. Reactant andproduct conformations were optimized with a DFT method using PBE0 function. The Evans-Polanyi relationshipwas used to calculate the rate of self- and cross-propagation of monomers. The results showed that thereactivity ratio of 2-perfluorooctyl ethyl methacrylate was found to be higher than that of methylmethacrylate. In addition, it was observed that the reaction conditions caused the random polymer structuredue to the different rate constants in self and cross propagation.