Hydrogenated acrylonitrile–butadiene rubber (HNBR) is widely used in automotive and sealing applications due to its oil resistance and mechanical durability; however, its long-term performance is significantly influenced by the curing chemistry. Sulfur vulcanization offers superior elasticity but restricted thermal stability, while peroxide curing improves heat resistance at the expense of flexibility. In this study, we investigate hybrid sulfur–peroxide curing to integrate these benefits. The hybrid pathway encompasses competitive and sequential processes, such as partial radical quenching and accelerator oxidation, resulting in a dual crosslink network. Dynamic mechanical, thermal, and temperature scanning stress relaxation (TSSR) evaluations demonstrate that hybrid systems provide precise modulation of the operational temperature–frequency range, broaden the glass-transition relaxation, and control stress dissipation. The coexistence of sulfur and C–C crosslinks results in a heterogeneous structure characterized by diverse crosslink densities and bond energies, leading to numerous relaxation modes and an optimal blend of elasticity, strength, and thermal stability. Microscopy confirms the absence of phase separation, indicating that hybrid vulcanization is a viable approach for producing robust, high-performance HNBR elastomers.

This study investigates the effects of renewable chopped cellulose fiber (CCleF) on the physical and mechanical properties, oil resistance, and thermal-oxidative aging behavior of acrylonitrile-butadiene rubber (NBR), aiming to determine the optimal filler content. CCleF/NBR composites with varying CCleF loadings were prepared and systematically characterized through analyses of vulcanization behavior, three-dimensional morphology, mechanical properties, thermal-oxidative aging, and oil resistance. The results indicate that the composite with 3 phr CCleF exhibits uniform fiber dispersion and optimal overall performance, showing enhanced processability, a reduced vulcanization time, and improved physical and mechanical properties. After thermal-oxygen aging, the composite demonstrated superior stability: the percentage change in tensile modulus, rebound resilience, and DIN abrasion decreased significantly by 13.73, 49.82, and 74.9%, respectively, while the aging coefficient reached 0.86. Notably, this composite also exhibited excellent oil resistance, with a volume expansion rate of 7.24%, which is 13.1% lower than that of unfilled NBR. Correspondingly, the tensile product’s retention rate decreased by 37.72%, while rebound resilience and abrasion resistance improved. This study demonstrates that incorporating 3 phr CCleF is a practical approach to achieving high-performance NBR, providing a material basis for its use in demanding environments such as the petrochemical industry.

This study explores the application of thermo-oxidative reclaimed ground tire rubber (RGTR) in natural rubber (NR)/styrene butadiene rubber (SBR) composite, focusing on its impact on morphology, mechanical properties, rheological behavior, vulcanization characteristics, aging resistance, tear strength and abrasion resistance. The findings revealed that RGTR enhances the tear strength and abrasion resistance of NR/SBR composites while maintaining comparable tensile strength, elongation at break, and modulus. The incorporation of RGTR reduced Mooney viscosity of the NR/SBR composites and improved flowability. It also shortened the vulcanization time and enhanced vulcanization efficiency. The NR/SBR composites with RGTR loadings below 60 phr exhibited optimal performance, achieved a maximum tear strength of 93.77 N/mm and improved abrasion resistance. However, higher RGTR content led to increased agglomeration, as evidenced by scanning electron microscopy (SEM), which showed finer dispersion at lower RGTR contents and larger aggregates at higher loadings. These findings demonstrate the potential of RGTR as a sustainable additive for enhancing specific properties in NR/SBR composites, contributing to both performance optimization and waste tire management.

Ground sugarcane bagasse (GSB), an agro-waste rich in lignocellulosic components, was studied as a sustainable bio-filler in natural rubber (NR) tread compounds to lessen reliance on petroleum-derived carbon black (CB). A control formulation with 45 phr CB was compared to hybrid formulations with 40, 35, and 30 phr CB mixed with 5, 10, and 15 phr GSB. Tensile strength 13.1 MPa, elongation at break 700%, and hardness 67 Shore A were all optimally balanced by the compound containing 10 phr GSB (S2), while also exhibiting good cure behavior and thermal stability. Improved tire performance characteristics were confirmed by a dynamic mechanical study, which showed that tan δ at 60 °C decreased by 8.0% (resulting in lower rolling resistance) and increased by 3.9% (improving wet traction) at 0°C. The Payne effect showed improved filler dispersion as a result of GSB partially replacing CB. The results show that appropriately dispersed GSB can partially reinforce NR, enhancing energy efficiency and sustainability. However, larger GSB loadings decrease modulus, tear strength, and abrasion resistance due to lower interfacial adhesion and the presence of micro-voids. According to this study, pulverized sugarcane bagasse shows promise as an environmentally friendly filler for green tire applications, promoting the circular economy and lowering the carbon footprint of rubber compounding.

The need to recycle elastomeric waste requires studying its viability in industrial applications. This study investigates the feasibility of recycling elastomeric waste by analyzing whether virgin ethylene-propylene-diene monomer (EPDM) can be replaced by blends of virgin EPDM and thermomechanically and microwave devulcanized EPDM (EPDMd) in industrial applications from the perspective of environmental degradation. Two types of samples were examined: conventional EPDM used to roof membranes, and EPDM blended with different amounts (20, 40, and 50 phr) of EPDMd. Samples were subjected to natural aging in coastal and mountainous environments. Results show that mechanical properties decline with higher EPDMd content and, to a lesser degree, with prolonged outdoor exposure. The coastal climate proved more aggressive than the mountainous one when EPDMd content exceeded 40 phr. Zinc stearate (ZnSt₂), a byproduct of vulcanization, was found to influence the evolution of the mechanical behavior. The combined analysis of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), abrasion tests, and thermogravimetric analysis (TGA) provided insights into the degradation processes of these elastomeric blends.