Thermal depolymerization (TDP) is the process of converting a polymer into a monomer or a mixture of monomers,[1] by predominantly thermal means. It may be catalyzed or un-catalyzed and is distinct from other forms of depolymerization which may rely on the use of chemicals or biological action. This process is associated with an increase in entropy.
For most polymers, thermal depolymerization is chaotic process, giving a mixture of volatile compounds. Materials may be depolymerized in this way during waste management, with the volatile components produced being burnt as a form of synthetic fuel in a waste-to-energy process. For other polymers, thermal depolymerization is an ordered process giving a single product, or limited range of products; these transformations are usually more valuable and form the basis of some plastic recycling technologies.[2]