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

- Quantification of TESPT grafting on butadiene rubber by liquid-state NMR spectroscopy.
- Grafting and pre-crosslinking reactions are favored by the temperature increasing.
- Grafting rates were measured thanks to deconvolution or after free silane extraction.

Interactions between butadiene rubber (BR) and polysulfide silane (TESPT) were studied by liquid state NMR spectroscopy. 1H, 13C and DOSY spectra highlighted the presence of pre-crosslinking and grafting reactions in BR/TESPT blends mixed with dump temperatures between 155 and 180 °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 1H NMR signals of crude blends and 1H 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.

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