Development of recyclable rubber compounds using sustainable additives

The processing of rubber waste is growing in commercial interest, although vulcanized rubber remains difficult to recycle due to the incorporation of new additives and the strong interactions between rubber and fillers. This creates a significant challenge for effective rubber waste management, as current recycling methods often remain inadequate. Therefore, there is an urgent need for innovative approaches to prevent environmental pollution and promote sustainable solutions. Optimizing the self-healing and recyclability of rubber materials presents one promising avenue in this context. This study aims to develop more environmentally responsible solutions in the rubber materials domain by modifying epoxidized natural rubber with bio-based curatives, additives, and fillers to incorporate recyclability features. The research activity involves the preparation of rubber compounds containing oil-based, bio-based, and waste-derived fillers, followed by curing and processing. Mechanical, compositional, morphological, and thermal characterizations are performed for each formulation. Finally, self-healing and recyclability protocols are implemented to evaluate the reuse and recycling potential of the prepared compounds. The developed compounds showed self-healing capability in all conditions studied. The results obtained for almost all formulations are comparable, indicating that the self-healing efficiency is maintained regardless of the filler, especially at short exposure times and high temperatures. In contrast, regarding the recycling efficiency, all formulations maintained good mechanical and thermal properties, even after three recycling cycles, demonstrating satisfactory structural integrity and stability. The proposed approach supports the development of the circular economy and environmental sustainability by promoting the design of materials with enhanced durability and extended life cycles through multiple reuse and recycling processes.