Distribution Of Fillers In (X)IIR And SSBR Blends

The distribution of filler in IIR/SSBR blends as well as in BIIR/SSBR blends was analyzed both qualitatively and quantitatively. In addition, effects of filler distribution on the performance of blends are investigated.First, Buty 301 and SSBR 4526-0 were used as rubber matrix and high structured carbon black (N234) and silica (Vulkasil N)with different silanization degree were chosen as fillers to investigate the change in filler distribution and rubber property with respect to the amounts of filler and the blend ratio of rubber compound. Afterwards, blends of Buty 301 and BUR X2 were used to study the distribution of carbon black N234 in the rubber blends, influence on processing properties, mechanical properties as well as dynamic properties for the rubber compound were also investigated.The results indicated that with the increase of carbon black content, the Mooney viscosity, the maximum and the minimum torque increased significantly while the curing time was shortened. The rubber blend did not show obvious advantage over the unblended ones in basic mechanical properties. Payne effect characterization showed that the interaction between fillers in IIR is stronger than that in SSBR, which was in good consistence with the result shown by bound rubber content measurement that the interaction between SSBR and filler was stronger than that in IIR. Thus a qualitative conclusion can be made that the carbon blank tended to distribute in SSBR phase. The results from DMA results indicated that for the blend rubber consisting of IIR and SSBR with similar polarity and Mooney viscosity, carbon black N234 tended to distribute more in the SSBR phase with higher degree of unsaturation. The above results were in good consistence with the characterization results from RPA and bound rubber measurement.In silica filled system, the addition of coupling agent can improve the dispersion of silica and enhance the interaction between filler and rubber. It can also make the Mooney viscosity, curing characteristics, basic mechanical properties as well as the interaction between filler and rubber present a more regular change. Meanwhile, the quantitative results of silica distribution showed that the silica distributes more easily in SSBR phase just like carbon black.The co-vulcanization characteristic of BIIR/SSBR system was better than IIR/SSBR blend system. The results of the bound rubber showed that in the compounded rubber, carbon black combined easily with BⅡR, which was different from the distribution of carbon black in vulcanized rubber calculated by DMA. The basic mechanical properties for the BIIR/SSBR blend rubber were similar to those for a single rubber but much better than those for IIR/SSBR blend rubbers. Addition of BⅡR can not only improved the wet skid resistance but also lowered the rolling resistance. Especially, when the BIIR/SSBR was 70/30 and the carbon black content was 45 phr, the wet skid resistance and the rolling resistance was well balanced and the vulcanizate had better mechanical properties.