1. Dipartimento di Chimica, Materiali ed Ingegneria Chimica, Politecnico di Milano, Via Mancinelli 7, 20131 Milano, Italy;2. Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang‐Pauli Strasse 10, 8093 Zurich, Switzerland
Abstract:
Free‐radical polymerization of vinyl chloride is investigated computationally with special attention to the secondary reactions involving mid‐chain radicals (MCRs). Namely, the rate constants of backbiting, chain scission, chain transfer, and propagation reactions are evaluated using a density functional theory method. The rate coefficients of such reactions are estimated taking into account the position of the radical along the chain as well as its distance from the chain‐end. In particular 1:5, 5:1, and 5:9 backbiting are the most relevant secondary reactions, followed by the slower propagation of MCRs. Finally, a kinetic model of suspension polymerization including the investigated reactions is developed, in order to determine their impact on the quality of the final polymer.
