COMPUTER-SIMULATION OF SULFUR VULCANIZATION

Recent advances in polymer network modelling techniques have enabled t he development of coarse-grained computer algorithms which predict pol ymer gelation while maintaining chemical reactivity. These computer si mulations have proven to be a powerful tool in the study of network mi crostructure, otherwise not obtainable. Previous applications of the a lgorithms to irradiation and end-linking have given insight into the i nterconnectivity of chains and the formation of network defects. We pr opose modifications to this already existing and tested algorithm in o rder to model sulfur vulcanization. The modifications include the intr oduction of reactive crosslinkers off the constituent polymer backbone s. 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 pre dicted values of moduli from simulation are particularly encouraging. Upon comparison, the moduli determined from simulation varied from 1-1 5% for the experimental systems examined. This is accepted as very goo d agreement in the light of the absence of accounting for chain entang lements. The paper also reports results for network sub-structures suc h as dangling chain ends and intramolecular loops.