- Journal of the Turkish Chemical Society Section A: Chemistry
- Vol: 3 Issue: 3 Special Issue
- UNDERSTANDING THE BEHAVIOUR OF SULPHUR-CENTRED RADICALS DURING POLYMER SELF-HEALING
UNDERSTANDING THE BEHAVIOUR OF SULPHUR-CENTRED RADICALS DURING POLYMER SELF-HEALING
Authors : Isa Degirmenci, Michelle L. Coote
Pages : 707-720
Doi:10.18596/jotcsa.287305
View : 3 | Download : 1
Publication Date : 2017-01-08
Article Type : Other
Abstract :High-level ab initio molecular orbital theory calculations have been used to study self-healing mechanism of materials based on thiuram disulfides and their derivatives (S=C(Z)S–SC(Z)=S, for Z = CH 3 , NEt 2 , N(Et)CH 2 CH 2 OH, Ph, Bz), and the effects of these Z-substituents on their efficacy. The relative contributions of cross-over and reversible addition fragmentation chain transfer reactions were ascertained, and the likelihood of chain-breaking side reactions was assessed. To rationalize the results, the various stabilization energies of the radicals and closed-shell species were also evaluated. The study revealed that the self-healing mechanism of thiuram disulfides follows predominantly the cross-over reaction because of the high energies of intermediate radicals in the chain transfer mechanism. Based on the study, the most effective self-healing materials are predicted to contain amines as Z-groups, while those containing benzyl and its derivatives are most likely to undergo side reactions.Keywords :