Researching The Influence Of Processing On Bound Rubber Of SBR’s System

Bound rubber used to call ‘rubber gel’, which formed by the interaction between fillers and polymer molecule. These parts of rubber cannot be extracted by the solvent like benzene or toluene. There are a lot of classical rubber theories derived from the phenomenon of bound rubber. What is more, it plays a significant role in guiding the tire rubber processing so as to develop a tire with less volume loss and lower rolling resistance. In this article, the SBR was selected as the matrix, which firstly was filled by varying types of Carbon black(N220,N330,N550,N774) with various degree of particle structure. The influence of filler structure both on the amount of bound rubber and the mechanical properties of SBR vulcanization had been studied. It showed that there was a significant 37.4% of bound rubber from the SBR/N774 to SBR/N220, reaching by 38.2%. The relevant of SBR/N220 vulcanization got the best mechanical property with 30.4MPa in tensile strength. In addition, the rheological behavior of the rubber-filler system was observed through RPA2000 and DMA devices, which would give us well detail about the modulus and the tanδ’s changing track. Not surprisingly, the SBR/N220 vulcanization had the least value of tanδmax, which was 0.88, and large magnitude of Payne effect. Besides, the processing of rubber and filler maxing was carried out under specific situations, such as the various maxing time and the different rotational speed. Likewise, the effect of rotating speed and maxing time on the mechanism and rheological charateristics of SBR/N220 system had been studied through some lab equipments, like RPA 2000. The mechanical property of the composite kept rising from 21.7MPa of 20 rpm to 30.4MPa of 40 rpm. At the same time, the amount of bound rubber reached the maximum- 32.5%. The magnitude of Payne effect showed the same tendency of the amount of bound rubber, which sensitively reflected the interaction between filler and rubber chain and the state of the network. Apart from the filler of carbon black, the silica, as becoming more popular filler among the tire industry, had been studied. Similar to SBR/Carbon black system, while the bound rubber was 40.7% with 30 rpm, the vulcanization had the best both mechanical and rheological properties, like 22.94 MPa of tensile strength and least value of tanδmax – 0.92. For the maxing time, the vulcanization of SBR/WCB got the best properties, 23.58 MPa of tensile and 0.88 of tanδmax, at 15 min of maxing time with 43.9%. In the end, the effect of the amount of coupling agent(Si69) on the bound rubber formed and the properties of SBR/Silica system had been studied. This experiment part on one hand showed the effect of coupling agent on modifying the filler. On the other hand, it to some degree proved the bound rubber theory on reinforcing the rubber vulcanization system. The result showed that the bound rubber amount arrived by 41.8% with 5 phr Si69, and the tentile strength rised by 21.98 MPa.