Study of the crosslink density, dynamo-mechanical behaviour and microstructure of hot and cold SBR vulcanizates

Vulcanizates of hot and cold styrene-butadiene rubber (SBR) were prepared with five different cure systems based on sulphur, 2-mercaptobenzothiazole disulphide (MBTS) and tetramethylthiuram disulphide (TMTD). The degree of crosslinking was investigated by swelling in benzene and stress-strain analysis. Thiol-amine chemical probes were employed to determine the type of crosslinks in the sulphur vulcanizates, and their dynamic-mechanical properties and thermal stability were studied in both the raw (non-crosslinked) and crosslinked state. The butadiene microstructure and the total unsaturation were determined by Raman spectroscopy. The influence of the crosslink density and the type of crosslink formed on the measured properties is discussed.