MECHANICAL-PROPERTIES OF CARBON-BLACK FILLED AND ENTANGLED ELASTOMERS

The stress-strain behaviour of unfilled and carbon black filled SBR 15 00 vulcanizates is investigated. Using the conformational tube model, which has been extended to filled polymer networks, three important mi croscopic quantities are estimated: the average molecular mass of the mobile network chains, the elastically effective density of polymer-fi ller contacts, and the microscopic lateral tube dimension. The values agree with previous calculations as well as experiments on typical ela stomers. The observation of a large contribution of entanglements to t he elastic modulus favors the entanglement/bound rubber model to expla in effects of carbon black on filled rubber properties. The tight coup ling between bound rubber and carbon black surface is discussed in con nection with entropic effects of disorder induced