Thermal and catalytic decomposition of polyethylene and polypropylene

Abstract The decomposition of polyethylene and polypropylene over HZSM-5 zeolite catalyst and a catalyst modified with orthophosphoric acid (PZSM-5) have been compared. The gaseous and liquid products depend on the polymer type, its structure, on the catalyst, its acidity and steric effect. The gaseous products contain a large C3 fraction, while the liquid products from both polymers contain mainly aromatic hydrocarbons. Catalytic decomposition increases the amount of gaseous products, lowers the liquid fraction, and changes the composition of these products compared to uncatalytic decomposition.