Monomer Recycling of Waste Poly (Ethylene Terephthalate) and its Life Cycle Assessment

Etsu Yamada*,**, Kotonaga Matsui**, Yasuro Fuse* and Akira Oku**
* Center for Environmental Science,
** Department of Chemistry and Material Technology,
Kyoto Institute of Technology
+ Correspondence should be addressed to Etsu Yamada:
(Matsugasaki, Sakyo-ku, Kyoto, 606-8585 Japan)

Abstract
Alkali decomposition of poly (ethylene terephthalate) (PET) with sodium hydroxide in ethylene glycol (EG) revealed to be an efficient method for the reproduction of pure terephthalic acid (TPA) and EG from recovered PET plastic wastes. This was done under mild conditions at 180*C[Celsius degeree] for 15min. The recovered TPA and EG contain no impurities such as dyes or metals.
In this study, both the environmental loading (using inventory analysis) and cost charge concerning the reproduction of PET resin from the monomers recovered from this monomer recycling method were estimated. In comparison with the production of virgin PET resin from crude oil, this monomer recycling process can reduce environmental loading, such as energy consumption and pollution, to the extent that it can be used as a practical method for the recycling of PET plastics.

Key words: poly (ethylene terephthalate) (PET), monomer recycling of PET, terephthalic acid, ethylene glycol, life cycle assessment