TY - JOUR
T1 - Turning Vulcanized Natural Rubber into a Self-Healing Polymer
T2 - Effect of the Disulfide/Polysulfide Ratio
AU - Hernandez Santana, Marianella
AU - Grande, Antonio
AU - Dierkes, W.
AU - Bijleveld, Johan
PY - 2016
Y1 - 2016
N2 - A self-healing sulfur vulcanized natural rubber (NR) is here reported using the common ingredients in a traditional NR formulation. The dynamic character of the di- and polysulfide bonds naturally present in covalently cross-linked rubbers was found to be responsible for the healing ability and the full recovery of mechanical properties at moderate temperatures provided the material was employed in a nonfully cured starting state. Results show that a compromise between mechanical performance and healing capability can be reached by tailoring the amount of sulfur, the cross-linking density, and the disulfide/polysulfide ratio. The healing efficiency was found to depend on the postcuring storage time, the time between damage creation and re-establishment of mechanical contact, and the actual healing time. Furthermore, a dedicated electron spin resonance (ESR) test allowed establishing the underlying healing principle based on temperature-induced free sulfur radicals. The main observations presented here can serve as the basis for the design and preparation of other self-healing polymers with long-term durability based on di-/ polysulfide bridges and other reversible moieties
AB - A self-healing sulfur vulcanized natural rubber (NR) is here reported using the common ingredients in a traditional NR formulation. The dynamic character of the di- and polysulfide bonds naturally present in covalently cross-linked rubbers was found to be responsible for the healing ability and the full recovery of mechanical properties at moderate temperatures provided the material was employed in a nonfully cured starting state. Results show that a compromise between mechanical performance and healing capability can be reached by tailoring the amount of sulfur, the cross-linking density, and the disulfide/polysulfide ratio. The healing efficiency was found to depend on the postcuring storage time, the time between damage creation and re-establishment of mechanical contact, and the actual healing time. Furthermore, a dedicated electron spin resonance (ESR) test allowed establishing the underlying healing principle based on temperature-induced free sulfur radicals. The main observations presented here can serve as the basis for the design and preparation of other self-healing polymers with long-term durability based on di-/ polysulfide bridges and other reversible moieties
KW - Vulcanized natural rubber
KW - Degree of curing
KW - Self-healing
KW - Disulfides, Polysulfides
KW - Elastomer
KW - Time dependence
KW - Electron spin resonance
U2 - 10.1021/acssuschemeng.6b01760
DO - 10.1021/acssuschemeng.6b01760
M3 - Article
SN - 2168-0485
SP - 5776−5784
JO - ACS Sustainable Chemistry and Engineering
JF - ACS Sustainable Chemistry and Engineering
ER -