Depolymerization of Polyester Fibers with Dimethyl Carbonate-Aided Methanolysis
Shinji Tanaka, Maito Koga, Takashi KURAGANO, Atsuko Ogawa, Hibiki Ogiwara, Kazuhiko Sato, Yumiko Nakajima
Abstract
Polyester fibers, comprising mostly poly(ethylene terephthalate) with high crystalline content, represent the most commonly produced plastic for ubiquitous textiles, and approximately 60 million tons are manufactured annually worldwide. Considering the social issues of mismanaged waste produced from used textile products, there is an urgent demand for sustainable waste polyester fiber recycling methods. We developed a low-temperature, rapid, and efficient depolymerization method for recycling polyester fibers. By utilizing methanolysis with dimethyl carbonate as a trapping agent for ethylene glycol, depolymerization of polyester fibers from textile products proceeded at 50 °C for 2 h, affording dimethyl terephthalate (DMT) in a >90% yield. This strategy allowed us to depolymerize even practical polyester textiles blended with other fibers to selectively isolate DMT in high yields. This method was also applicable for colored polyester textiles, and analytically pure DMT was isolated via depolymerization and decolorization processes.