Abstract:

The stress-strain behavior of rubber compounds is one of the key items to determine its application performance， and the different service conditions， especially the strain rate， have variable requirements for the performance of rubber compounds. The influence of tension strain rate on the stress-strain behavior of styrene butadiene rubber （SBR） vulcanizates filled with 3 kinds of carbon black was investigated from the point of view of rubber reinforcement. It was found that the stress at a given elongation of any SBR vulcanizate increases with increasing strain rate， and the more reinforcing the carbon black， the higher increment rate the stresses. For any given SBR vulcanizate， the stress increment rate decreases with the increase in strain. As the strain exceeds the critical points， such as 300%， the effect of strain rate on the rate of stress increase is becoming equivalent and independent of carbon black grades. From a filler reinforcement point of view， the tensile modulus of filled vulcanizates in the plateau region is governed by the surface activity of the carbon black. In quasi-static tension test， the networking of carbon black in vulcanizate will be gradually broken with increasing strain， which the break-up is predominantly controlled by strain rather than strain rate.

Key words: Styrene butadiene rubber vulcanizate, Carbon black, Stress-strain behavior, Surface activity, Filler networking