Performance of acid treated natural zeolites in catalytic degradation of polypropylene

The performance of several differently treated natural zeolites in the degradation of polypropylene was investigated in this study. The composition of degradation products, especially liquid fractions resulted over studied catalysts, was compared to understand the role of catalysts. The degradation was carried out with a mixture of polypropylene and catalysts at 400 degreesC. The liquid products from the catalytic degradation of polypropylene are distributed in a narrower range of carbon numbers compared with those obtained by thermal degradation. With boric and phosphoric acid treated natural zeolites, the distribution of liquid products shifted to lower numbers of carbon atoms due to the increase of pore volume and surface area. The increase of temperature accelerated the cracking of intermediate degraded fragments to lower hydrocarbons. (C) 2002 Elsevier Science B.V. All rights reserved.