DEGRADATION OF PURE AND WASTE PVC AND PET IN THE PRESENCE OF MODIFIED POROUS CATALYSTS

The catalytic degradation of pure and mixed polymers such as poly-(vinylchloride) (PVC) and poly-(ethylenterephthalat) (PET) was followed by thermal analytical method (TA) and was performed in a laboratory batch system (LBS) using modified ZSM-5, MCM-41 and hydrotalcites based catalysts. In degradation of PET, the acidic H-ZSM-5 resulted in less liquid products and more gaseous components than the other, transition metal containing catalysts. The degradation of PVC takes place in two steps, the first is the departure of HCl at about 300 oC followed by formation of aromatic hydrocarbons. Minimal residue could be obtained over Fe,Mg,Al-hydrotalcites and mixed oxide catalyst. From the results obtained it can be concluded that not only the catalyst structure but also the polymer structure determines the activity of a micro- or mesoporous material in the catalytic degradation of plastics or plastic wastes. Therefore, different optimal conditions (catalyst and reaction temperature) can be applied for each plastics studied (pure, mixed and waste) in thermal treatment. Keywords: plastic pyrolysis, porous catalysts, degradation, polymer waste, PVC, PE