Recycling of Waste Poly(Ethylene Terephthalate) with Naphthalene and Neutral Water

Abstract The waste poly(ethylene terephthalate) (PET) powder dissolution/reprecipitation was carried out in a batch operation at atmospheric pressure at various temperatures ranging from 180–220°C at temperature intervals of 10°C. Particle sizes of the waste PET ranged from 50–512.5 µm and operation time, which ranged from 30–90 min, were optimized. Dissolution/reprecipitation of the waste PET was carried out in naphthalene (solvent) and neutral water (nonsolvent), respectively. Dissolution/reprecipitation of the waste PET was increased with operation time and temperature. Dissolution/reprecipitation of PET was decreased with increase in the particle size of the waste PET. The waste PET particle size and agitator speed required for complete recycling of the waste PET were also optimized. Analyses of the waste PET and the recycled PET collected after the reprecipitation process was undertaken by determination of various physical properties. The operation applied at lesser time and with cheaper solvent/nonsolvent, resulted in excellent quality of the recycled PET collected after the reprecipitation process. This process of recycling of the waste PET has an industrial significance due to most economical operation for commercialization.