Tennis ball recycling through the use of selective dissolution and green solvent

This thesis work wants to analyse an innovative and sustainable approach for recycling the components of a tennis ball. Tennis balls are designed in a way that are non-biodegradable and of single use, especially at professional level. In addition, their production alone is not an eco-friendly process, since the nylon used is a petroleum-based product and the rubber comes from plantations that threaten plant biodiversity. Despite the great standardization achieved in the production of tennis balls, according to the International Tennis Federation, the heterogeneity of coupled materials and the nature of the chemical bonds established, make the separation of components in their pure form extremely complex to achieve. This technological gap, linked to the scarcity of scientific information in literature, represents the main obstacle towards a real closing of this product life cycle. The proposed process relies on selective dissolution and precipitation techniques to clean rubber. The solvent employed is the most effective among those evaluated in terms of sustainability and operational conditions. This methodology aims to optimize the properties of recovered raw materials while mitigating the environmental impact of the recycling process. The advantages and limitations of the process will be discussed. Following the process, several analyses were performed, including Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Infrared Fourier Transform Spectroscopy (FT-IR), compressive and tensile tests. The results obtained show that the proposed process is effective in separating the main component of the tennis ball, while preserving the main structural and mechanical characteristics of the recovered materials. Rubber and pulverized felt (mostly polyamide) recovered are suitable for new applications, offering a sustainable solution for the recycling of tennis ball and contributing to the exploitation of resources in a perspective of circular economy.