What are the key limitations of using recycled rubber in high-performance applications?

Using recycled rubber in high-performance applications faces several key limitations. Firstly, the mechanical properties of recycled rubber are generally lower than those of virgin rubber. The recycling process, especially mechanical grinding, can cause chain scission and degradation of the rubber, reducing its tensile strength, elasticity, and tear resistance. Secondly, recycled rubber often contains impurities and contaminants that can negatively affect its performance. These impurities may include fillers, additives, and other materials that were present in the original rubber product. Thirdly, the devulcanization process, while aimed at breaking down the cross-linked network, may not completely restore the original properties of the rubber. The devulcanized rubber may still have a lower molecular weight and a different cross-link density compared to virgin rubber. Fourthly, the variability in the composition of recycled rubber can make it difficult to control its properties and ensure consistent performance. Recycled rubber often comes from a mix of different rubber products with varying formulations, leading to batch-to-batch variations. Fifthly, the odor and color of recycled rubber can be undesirable for some applications. The recycled rubber may retain the odor of the original rubber product, and its color may be inconsistent or unattractive. Sixthly, the aging performance of recycled rubber may be inferior to that of virgin rubber. The recycled rubber may be more susceptible to oxidation and degradation over time, leading to a shorter service life. For example, while recycled rubber can be used in asphalt pavements, its use in high-performance tires is limited due to its lower mechanical strength and durability compared to virgin rubber.