Enhancing the sustainability of rubber materials: Dual benefits of wet mixing technology and recycled rubber's honeycomb reinforcement structure.

Abstract

The world's three leading tire manufacturers have proposed specific timelines for using recycled materials. For instance, Michelin targets an increase in the proportion of sustainable materials in tires to 40 % by 2030 and aims to produce 100 % of its tires from bio-based, renewable, or recyclable materials as of 2050. In such a context, this study introduced wet mixing technology to apply recycled rubber (RR) in highly wear-resistant tire tread compounds. This technique leverages the rubber's inherent crosslink density to enhance the mechanical performance of final products. The results indicated that wet mixing effectively addressed the high viscosity issue of RR. In the traditional dry mixing method, physical blending typically results in large particle sizes and suboptimal performance. In contrast, wet mixing reduced the rubber's hysteresis loss by 75 % and improved its rebound performance by 35.6 % at 23 °C, 60 °C, and 100 °C compared to traditional dry mixing. DIN volume abrasion was also reduced by 23.3 %. Remarkably, Akron abrasion nearly doubled its effect. Additionally, wet mixing regulated aggregate structure and formed a densely packed honeycomb-like structure within RR. Incorporating RR using wet mixing demonstrates noticeable advantages in carbon black/natural rubber/RR composite materials. This approach also presents a viable path to sustainable development in the rubber manufacturing industry.