Mehrdad Seifali Abbas-Abadi - Polymerization Engineering, Iran Polymer and Petrochemical Institute (IPPI), Tehran, Iran
Mehdi Nekoomanesh Haghighi - Polymerization Engineering, Iran Polymer and Petrochemical Institute (IPPI), Tehran, Iran
Hamid Yeganeh - Polymerization Engineering, Iran Polymer and Petrochemical Institute (IPPI), Tehran, Iran

Plastics have the big share of the municipal wastes in many countries and the waste plastics are bringing about a serious environmental problem [1]. Polypropylene (PP) is used inseveral markets, for instance, in food packaging, medical bags, computer components, automotive industry, pipes and generalcontainers. This versatility of PP is due to its good chemical resistance and its low density (good relation properties/weight). PP has a relatively high melting pointcompared with other similar polymers, thus being useful to contain hot substances. This material represents nowadays 22% of the thermoplastics’ market, with a strong increase since 1983 [2-3]. Thermal degradation of polymers has great interest as an alternative source of energy or chemical rawmaterials, as well as it contributes to the solution of environmental problems [4]. Pyrolysis is generally defined asthe controlled burning or heating of a material in the absence of oxygen [5] whereas Catalytic pyrolysis can improve the product selectivity and reduce the energy input [6].Liquefaction of waste plastics has been undertaken by several investigators, involving reactions in autoclave hightemperature and pressure reactors in the presence of hydrogen, or a hydrogen donor such as tetralin or oil and/or the presenceof catalysts [7]. The goal of this study is to investigate the different carrier gases effect on the products yield of polypropylene catalytic degradation