Characterization and recyclability analysis of motorcycle helmets. The Dainese case

Nowadays, in industrialized countries, the environmental sensitivity of industrial production is increasingly widespread. Therefore, it is essential to study the life cycles of products to understand their environmental impact and try to reduce it with new strategies that promote the circular economy. In this study is analysed, the recyclability of the fundamental components of a motorcycle helmet, produced by the Dainese company, world leader in the production of protective devices. Motorcycle helmets are mainly composed of polymeric and composite materials, so there is a huge production of these materials, which corresponds to a large impact on the environment caused by the accumulation of waste in landfills. In fact, helmets are not recycled so at the end of their life they are usually disposed in landfills or dispersed into the environment. To proceed with the analysis of recyclability, a representative helmet, the K1, was selected among the various helmets produced, because its impact in terms of volumes produced and sold is the largest of the company. In the first part of this work, the K1 is mechanically disassembled into all its components and the different materials present are distinguished and weighed. This first analysis shows that the main materials, that represent more than 80% of the helmet, are ABS (acrylonitrile butadiene styrene) PC (polycarbonate), EPS (expanded polystyrene) and PU+PES (polyurethane and polyester). After grinding the disassembled components, uncontaminated ABS, PC and EPS can be obtained through selective dissolution. The materials obtained are processed by injection moulding, which allows to obtain samples of recycled material that are thermally and mechanically characterized using TGA, DSC, FTIR, GPC, tensile and impact tests. All these processes are repeated for other K1 helmets, that have undergone an aging process in order to simulate the life cycle of the helmets. While PU and PES are subjected to various chemical processes of glycolysis, in order to find the optimal process parameters in terms of temperatures, catalysts, reagents, which allow to obtain a liquid polyol, one of the raw materials used to create a new polyurethane foam. Recycled polyols were analyzed using different instruments such as FTIR, Brookfield viscosimeter, Titrator, HPLC and GPC. While the new polyurethane foams were characterized using compression and thermal conductivity tests. The results of this study show that it is possible to create a recovery process for the materials present in motorcycle helmets, which can be successfully recycled and their properties remain such that they can be reuse either in the helmet or for other purposes.