Effects of Crosslink Characteristics on Density and Swelling Behaviour of Expanded Natural Rubber Vulcanisates

Expanded natural rubber was vulcanised using different techniques to obtain various types of crosslinking including flexible and rigid sulphur and peroxide linkages. Stress-strain measurement based on the Mooney-Rivlin equation was utilised to determine overall crosslink density of the rubber. The expanded NR vulcanisates produced were then characterised with respect to the apparent density and swelling behaviour, these properties being found to be dependent not only on the degree of crosslinking, but also on the type of chemical structure of the crosslink. This was also a suggestion that swelling behaviour was related to apparent foam density.