Rubber/silane reactions and grafting rates investigated by liquid-state NMR spectroscopy

Interactions between butadiene rubber (BR) and polysulfide silane (TESPT) were studied by liquid state NMR spectroscopy. H-1, C-13 and DOSY spectra highlighted the presence of pre-crosslinking and grafting reactions in BR/TESPT blends mixed with dump temperatures between 155 and 180 degrees C. Pre-crosslinking induced by the sulfur release of TESPT was evidenced at high temperature. The grafting rate of silane on BR chains was quantified thanks to deconvolution of H-1 NMR signals of crude blends and H-1 spectra analysis of blends after extraction of non-grafted silane. These two methods showed similar values of grafting rates and demonstrated the influence of the dump temperature on BR/silane reactions. (C) 2016 Elsevier Ltd. All rights reserved.