Thermal degradation and catalytic cracking of poly(ethylene terephthalate)

The percentage weight loss of poly(ethylene terephthalate) (PET) by thermal degradation and catalytic cracking reactions was investigated at atmospheric pressure. The extent of PET thermal degradation was little affected by the particle size, but tremendously affected by temperature between 400 and 500 degrees C. In PET catalytic cracking reactions, copper (II) chloride was the most active among tested catalysts. It reduced the carbonaceous residues and increased the percentage weight loss of PET about 3.5 times in comparison with thermal degradation at the same reaction conditions. Considering the weight loss of catalyst itself during the reaction, copper (II) chloride was still the most effective. Mixing catalysts and PET by impregnation demonstrated higher cracking ability than physical mixing. The results of PET catalytic cracking over copper (II) chloride demonstrated that the effect of temperature on the percentage weight loss was similar to thermal degradation but shortened cracking time. The optimal catalyst-to-PET weight ratio was 0.1. (C) 1999 Elsevier Science Ltd. All rights reserved.