Effect of the network topology on the tensile strength of natural rubber vulcanizate at elevated temperature

The influence of network topology on tensile strength at elevated temperature of natural rubber compounds vulcanized with different systems was studied. The tensile strength behavior of natural rubber at high strain is attributed to the capacity to crystallize on stretching. Variation of this property with the temperature and/or crosslink density was related, not only with the nature of the crosslinks, but also with their spatial distribution. In this sense, measurements of the freezing point depression of cyclohexane imbibed in the rubber matrix were used to evaluate the spatial distribution of the crosslinks.