Improvement of Carbon Black Material and Reduction of Tire Rolling Resistance for Benefits of Green Environment

Abstract

Carbon black is the major filler used in rubber compounds. The extent of carbon black in tire compounds is of the order of 60-70 phr (parts per hundred) this large amount of filler leads to filler-filler interaction and results in extensive hysteresis losses. In spite of numerous efforts put forward to replace carbon black partly by silica the efforts were not very fruitful because all the parameters needed to be satisfied, hence the efforts could not meet the desired criteria. Therefore, of late there is a change in strategy of using carbon black itself as the key filler but in a modified form that will reduce the filler-filler interactions. The impact of filler on rubber compound properties is greatly influenced by its dispersion and distribution nature into the rubber matrix which is greatly dependent on the affinity of filler towards the rubber molecules. Filler with improved affinity towards rubber molecules leads to higher filler -rubber interaction resulting improved filler dispersion and reduce the propensity of filler network formation in the rubber matrix.  As low filler-filler interaction and high filler-polymer interaction of modified carbon black results lower extent of filler network, lower extent of hysteresis energy is lost on application of cyclic deformation on the rubber compounds. Thus, tire made up with such types of rubber compounds would have lower hysteresis energy loss during service and would lead to lower tire rolling resistance. 

In the present research work an attempt has been made to functionalize carbon black by treating with benzyl tri ethyl ammonium chloride for enhancement of carbon black interaction with rubber molecules. Such treatment causes improved dispersion of carbon black and reduces the inter-aggregates interaction of carbon black in rubber matrix.  The compounding of benzyl tri ethyl ammonium chloride treated carbon black was carried out with natural rubber system as well synthetic rubber system such as solution styrene butadiene rubber system. It is observed that due to reduction of re-agglomeration of carbon black aggregates the filler - filler interaction was reduced significantly, leading to lower Payne effect and lower hysteresis loss. As lower hysteresis loss at 60oC temperature of rubber compounds is a measure of tire rolling resistance, thus functionalization of carbon black by benzyl tri ethyl ammonium chloride results lowering of tire rolling resistance and reduces the emission of greenhouse gases by vehicles benefiting the environment.

Keywords; carbon black modification, filler-filler interaction, dispersion, hysteresis, rolling resistance