Computer simulation of sulfur vulcanization

Abstract

Recent advances in polymer network modelling techniques have enabled the development of coarse-grained computer algorithms which predict polymer gelation while maintaining chemical reactivity. These computer simulations have proven to be a powerful tool in the study of network microstructure, otherwise not obtainable. Previous applications of the algorithms to irradiation and end-linking have given insight into the interconnectivity of chains and the formation of network defects. We propose modifications to this already existing and tested algorithm in order to model sulfur vulcanization. The modifications include the introduction of reactive crosslinkers off the constituent polymer backbones. The validation of the sulfur vulcanization simulation was performed with high-(Z)-poly(buta-1,4-diene) systems with TMTD employed as the crosslinker in order to assure mostly monosulfidic crosslinks. The predicted values of moduli from simulation are particularly encouraging. Upon comparison, the moduli determined from simulation varied from 1–15% for the experimental systems examined. This is accepted as very good agreement in the light of the absence of accounting for chain entanglements. The paper also reports results for network sub-structures such as dangling chain ends and intramolecular loops.