Thermal and Morphological Properties of Polyurethane Foams Prepared from Microwave-assisted Glycolyzed Products of PET Bottles Wastes

Polyethylene terephthalate (PET) waste from post-consumer soft drink bottles was depolymerized under microwave energy instead of conventional heating with diethylene glycol (DEG) at the molar ratio between PET and DEG of 1:4 in a modified domestic microwave oven at the irradiation power of 600 W. Zinc acetate, sodium carbonate and sodium bicarbonate were used as a catalyst at 0.5% by weight of PET. It was reported that replacement of conventional heating with microwave energy shortened the chemical reaction time significantly. Polyurethane foams were then successfully prepared from the glycolyzed products by reacting them with polymeric diphenylmethane diisocyanate and polyethylene glycol as a chain extender. Thermal and morphological properties of the prepared polyurethane foams were then studied. It was found that the thermal behavior of the prepared foams was similar while their morphology was affected by the catalyst used. The most uniform cell structure was observed when the glycolyzed product that used sodium bicarbonate as a catalyst was used to prepare polyurethane foam.