Degradation of Polypropylene over Activated Carbon Catalyst

Abstract

Catalytic effects of activated carbon on degradation of polypropylene were investigated at 477∼526°C by using a fixed-bed flow system. The catalyst was effective for the C-C bond scission of the chain and the dehydrocyclization of the aliphatic fragments with relatively low molecular weight. The degradation products obtained at 502°C and with the contact time of 35.0 g-cat⋅min/g-PP were distributed among C₁∼C₁₂ fractions and contained 20 wt% of aromatics. The amount of aromatics, of which the main components were m-xylene and 1, 3, 5-trimethylbenzene, corresponded to about two-thirds of that formed in degradation of polyethylene over activated carbon. Therefore, it was evident that the dehydrocyclization was difficult to occur in degradation of polypropylene, compared with the case of polyethylene. The degradation reaction over activated carbon seems to be initiated primarily by the abstraction of hydrogen atom bound at tertiary carbon on the catalyst surface.