Tire tread rubber compounds with ternary system filler based on carbon black, silica, and metakaolin: Contribution of silica/metakaolin content on the final properties

Abstract

Carbon black and high performance silica have been widely employed as binary system filler in tire tread formulations. This study evaluated the total and partial substitution of silica by metakaolin (MK) on the properties of tread rubber composites. Dynamic mechanical thermal analysis and abrasion tests were conducted as typical assessments of tire tread performance: rolling resistance (fuel consumption), wet traction (safety), and abrasion (durability). Further the energy spent by the equipment during the processing of formulations was also analyzed, as well as rheological and mechanical properties. A significant reduction of rolling resistance was obtained with 75% and 100% of silica substitution by MK, which could lead to lower heat buildup in tire tread applications, without showing negative effects on wet traction, although abrasion showed undesired results. The substitution of silica by MK also lowered energy demanded for processing. No major changes were observed in vulcanization parameters and mechanical properties, which is interesting considering the fact that MK is nonreinforce filler.

Evaluation of silane effect as a coupling agent for metakaolin

“…5 MK (Figure 3), on the other hand, showed no significant difference between the experiments with and without silane, giving rise to two hypotheses: the first is that no reaction occurred between silane and MK and the second is that there was also agglomerate breakage, but the equipment was not sensitive enough to identify it. In our previous work, 11 we found that the Payne effect of MK is lower than that of silica, which means MK agglomerates have lower interaction energy, making them more brittle.…”

“…where μ is the crosslink density, V r is the volume fraction of rubber in the swollen sample (equation (5)), V 0 is the molar volume of the solvent (106.29 mL mol −1 for toluene), and χ is the Flory–Huggins interaction parameter between the solvent and the elastomer (0.405 11 ):…”

“…In the case of MK, the specific effect of silane bis(triethoxysilylpropyl)tetrasulfide (TESPT) (Si69) is not completely known. Since our previous study 11 suggested a coupling effect of Si69 in MK, the objective of this article is to verify and elucidate this effect based on the rheometric properties, crosslink density, and morphology of tire tread compounds, drawing a parallel with the known coupling effect of silane in silica in these composites.…”

“…As such, the silicate surface had to be modified with alkyl ions to make the filler compatible with the matrix. In addition, in our previous study, 11 in which we investigated the ternary filler system using CB, silica, and metakaolin (MK), some of the results showed that silane might have affected the interaction between MK and the polymer, influencing the mechanical properties of the final composite.…”

Effect of Gear Pump Extrusion Processing on the Properties of Fiber Reinforced Rubber Composites

“…The larger the tan δ value is, the better the wet skid resistance. The tan δ at 60 • C is used to characterize the rolling resistance of the composite [28,29]. The higher the tanδ value is, the higher the rolling resistance.…”