**2.2 Advantages of plastic pyrolysis over other recycling methods**

Pyrolysis of waste PET plastic is a more sustainable way of waste management as it creates value. The residue from the tertiary recycling method can be further treated to produce secondary raw material. The advantages of pyrolysis are:


**Figure 3** shows the different stages in the chemical degradation process. It starts with the initiation step which involves homolytic breaking down of the carbon to carbon bonds either by random or end chain scission. The result is two radicals and it leads to propagation which is the hydrogen transfer reaction either by intra or intermolecular forming and unzipping leading to unstable free radicals. Then the final step termination of the free radicals forming unreactive materials.
