Poly (ethylene terephthalate) (PET) is the most popular thermoplastic polymer. The ever-growing production and utilization of PET has led to postconsumer waste disposal problems because of its nonbiodegradability. The chemical depolymerization of PET waste is a possible remedy, as it results in some recyclable products. The aminolytic depolymerization of PET bottle waste with hydrazine monohydrate by conventional and nonconventional (with microwave irradiation) heating was carried out with simple chemicals as catalysts, such as sodium acetate and sodium sulfate. The yield of the product was optimized through variations in the time of aminolysis, the catalyst concentration, and the PET:hydrazine monohydrate ratio. The pure product obtained in good yield (86%) was analyzed by Fourier transform infrared spectroscopy, NMR, and differential scanning calorimetry and was identified as terephthalic dihydrazide. (c) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012