There are three types of plastics recycling processes that use vacuum in one or more stages. 1. Mechanical recycling Mechanical recycling is the process of separating, grinding, and washing plastic waste before shredding it into flakes or melting and pressing it into pellets. Polymers do not change during this process, so they can be used again and again to create the same product or something similar. Globally, this is the most commonly used method and the simplest and most economical way to recycle plastic materials. It has a lower carbon footprint compared to other processes. Vacuum is used in the extrusion stages of this process. 2. Chemical recycling Chemical recycling is the most complex and expensive recycling process. The polymer’s chemical structures are altered and reprocessed, so the plastics can be used as virgin materials. Impurities, additives, dyes, and chemical defects are completely removed from the plastic waste. This method is less popular due to the lack of technologies that can reliably alter polymer structures on an industrial scale. Vacuum is used in the extrusion and pyrolysis stages of this process. 3. Physical recycling During physical recycling, the shredded plastic is dissolved in a solvent solution. The solvent and any impurities are then evaporated and degassed under vacuum, leaving behind only the polymers in liquid form. Unlike in chemical recycling, the polymer chains are not broken, so the plastic is not destroyed. It can therefore be retrieved and used again, without having to begin the process from scratch. This process allows types of otherwise non-recyclable plastic to be recycled. It also makes it possible to recycle mixed plastic waste, which would be difficult or nearly impossible in a mechanical process. By introducing different solvents, different polymer types can be selectively dissolved and recovered.