Effect of Polymer Matrix on Kinetics and Mechanism of Carbene Reactions

The features of the kinetics and mechanism of the cage radical reactions initiated by carbenes in solid polymers has been considered. The low temperature reaction of arylcarbenes is their interaction in clusters with formation of biradicals (BR). The yield of BR is a measure of the distribution non-homogeneity of the carbene precursors in polymers. The reaction of BR formation is a probe to study the molecular dynamics at cryogenic temperatures. The main factor determining the kinetic non-equivalence of triplet carbenes in the low temperature reaction of the hydrogen atom abstraction is the dispersion of the cage distances between carbenes and C–H bonds of macromolecules. The strong effect of structural modifications in filled polymers on the thermal decay of carbenes has been established. The matrix effect on the mechanism of the product formation in the carbene reactions, associated with the relaxation processes, has been recognised by the polyvinylalcohol cross-linkage. The advantage of polyisoprene stabilisation against thermoxidation by the phenol grafting in carbene synthesis has been shown.