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 atmospher ic pressure. The extent of PET thermal degradation was little affected by t he particle size, but tremendously affected by temperature between 400 and 500 degrees C. In PET catalytic cracking reactions, copper (II) chloride wa s the most active among tested catalysts. It reduced the carbonaceous resid ues and increased the percentage weight loss of PET about 3.5 times in comp arison with thermal degradation at the same reaction conditions. Considerin g the weight loss of catalyst itself during the reaction, copper (II) chlor ide was still the most effective. Mixing catalysts and PET by impregnation demonstrated higher cracking ability than physical mixing. The results of P ET catalytic cracking over copper (II) chloride demonstrated that the effec t of temperature on the percentage weight loss was similar to thermal degra dation but shortened cracking time. The optimal catalyst-to-PET weight rati o was 0.1. (C) 1999 Elsevier Science Ltd. All rights reserved.