Theory and Applications of Thiyl Radicals in Polymer Chemistry

Abstract

Sulfur-centered radicals are important intermediates in radical-based polymerization processes, such as thiol-ene, thiol-yne, and certain free-radical polymerizations. They are also important in the repair mechanism of certain classes of self-healing materials. This chapter outlines these applications, with a special emphasis on their mechanistic aspects, as clarified by computational chemistry. Based on a review of the literature, we outline structure-reactivity considerations in reagent design for these processes, explain why sulfur-centered radical addition reactions are so reactive despite their thermodynamic unfavorability, and clarify the mechanism by which dithiuram-based self-healing polymers undergo reshuffling. © 2019 Elsevier Inc. All rights reserved.