The Green Rebirth of Silicone Waste: Recent Advances in Recycling Technologies

In silicone polymers, more than 90% of the main chain skeletons are linked by Si-O-Si bonds, with organic groups attached to the side chains and terminal groups. These polymers possess both organic and inorganic properties, exhibiting excellent resistance to high and low temperatures, good insulation, and weather resistance. They are widely used in aerospace, biomedical, electrical, transportation sectors and so on. Traditional methods for synthesizing silicones, such as carbon thermal reduction, have led to a sharp increase in global CO2 emissions. Consequently, developing technologies for the efficient degradation and recycling of small siloxane molecules from waste silicone polymers has become a research hotspot in the silicone industry. This paper explores the technical selection and research progress of physical recycling methods such as mechanical grinding, ultrasonication, and irradiation, as well as chemical recycling methods including pyrolysis and acid–base catalysis, in the field of silicone recycling. This holds significant practical implications for achieving a closed-loop cycle for silicones and reducing carbon emissions in the industry.