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Sulfidic linkages that are formed during the vulcanization process of natural rubber (NR) are unstable at a higher temperature and can be reversed into conjugated diene. To overcome such issue and to build a compound that is hostile to inversion and with increasing service life, anti‐reversion agent (ARA), for example, N,N′‐4,4′‐diphenylmethyene bismaleimide (BMDM), is added into the formulation. This work explains the conjugation reaction mechanism of conjugated diene and BMDM by means of gas chromatography–mass spectrometry and Fourier transform infrared spectroscopy. The first phase of this study is associated with the change in ARA dosage keeping ZnO dosage the same. It is observed that 5 phr of BMDM and 2 phr ZnO combination (ARA4) shows lowest reversion at 160°C. The modulus value at 300% elongation increased 12% by the incorporation of BMDM as compared to the compound of no BMDM (ARA1). The second part is all about keeping BMDM dosage the same at 5 phr level and varying ZnO phr by 3, 4, and 5. From the overall results, it is observed that at a suitable dosage of BMDM and ZnO (5 phr BMDM and 3 phr ZnO combination [ARA5]), least reversion can be achieved and vulcanizates containing optimized BMDM and ZnO show better retention properties after aerobic aging as compared to ARA1.

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In this study, solution grade styrene-butadiene rubber (SSBR) compound was prepared by partial replacement of silica with lignin. The compounds were designed and optimised using an L9 orthogonal array (using Taguchi method) targeting 'magic triangle'. Cure rate index (CRI), reinforcement index (RI) and hysteresis loss (loss tangent at 60°C) were considered as the responses. Thermo-gravimetric analysis and Differential scanning calorimeter is used to assess thermal degradation and intramolecular reactivity of lignin. Morphological analysis of the composites has instituted the fact that above 20% replacement of synthetic silica by lignin results in re-agglomeration of filler particles due to inferior dispersion. Response analysis through ANOVA coupled with an experimental study on physico-mechanical and dynamic-mechanical properties has manifested that SSBR with 58% vinyl content with 40:10 silica: lignin compounded at 160°C with 10% silane coupling agent (SCA) with respect to silica at factorial levels furnished a 'magic triangle' optimised tyre tread compound.

Hysteresis characteristics of high modulus low shrinkage (HMLS) polyester tire yarn and cord were evaluated to determine “specific work loss,” which indicate its heat generation characteristics. Test parameters were selectively chosen, considering the service conditions of high-speed passenger radial tires in which HMLS polyester tire cords are predominantly used. Specific work loss was found to increase exponentially with the increase in extent of stress relief. Dynamic property of this yarn and cord was also studied to determine “loss tangent (tan δ),” which influences rolling resistance of tires in service. A good correlation has been found between specific work loss of hysteresis test (a slow speed test) and tan δ of dynamic test (a high-speed test). Dynamic property of polyester dipped cord was investigated for a wide range of temperatures (100–180 °C) and frequencies (5–25 Hz). Tan δ at 100 °C was found to be relatively low and its magnitude remained at the same level for a wide range of frequencies. This is a favorable condition for the high-speed passenger radial tires, made out of HMLS polyester tire yarn. Microstructure of HMLS polyester yarn was analyzed. Crystallinity is around 43% (measured by Wide angle x-ray scattering); crystal width and long period are 61 and 142 Å, respectively.