Treatment of SMC composite waste for recycling as reinforcing fillers in thermoplastics

Needs for recycling thermoset composite materials are considerably increasing. Unfortunately, such materials are particularly difficult to recycle due to their crosslinked nature. In this paper, we focus on the case of Sheet Moulding Compounds (SMC), which consist of an unsaturated polyester filled with glass fibres and calcium carbonate. We consider the possibilities of mechanical treatments allowing to obtain ground fractions that could be used as fillers for the reinforcement of thermoplastics. Two processes are described and compared with an existing industrial one. Finally, optimised fractions of SMC waste are introduced into polypropylene, leading to promising results in term of mechanical properties.