Material Separation from Polyester/Cotton Blended Fabrics Using Hydrothermal Treatment

Mei Matsumura; Jun Inagaki; Ryo Yamada; Natsuko Tashiro; Katsuya Ito; Mitsuru Sasaki

doi:10.1021/acsomega.3c09350

Material Separation from Polyester/Cotton Blended Fabrics Using Hydrothermal Treatment

ACS Omega. 2024 Mar 4;9(11):13125-13133. doi: 10.1021/acsomega.3c09350. eCollection 2024 Mar 19.

Authors

Mei Matsumura¹, Jun Inagaki², Ryo Yamada³, Natsuko Tashiro³, Katsuya Ito⁴, Mitsuru Sasaki^{5

6}

Affiliations

¹ Tsuruga Films Technology Center, Toyobo Co., Ltd., 10-24 Toyo-cho, Tsuruga, Fukui 914-8550, Japan.
² Frontier Materials Technology Center, Toyobo Co., Ltd., 2-1-1 Katata, Otsu, Shiga 520-0292, Japan.
³ Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.
⁴ Innovation Division, TOYOBO Co., Ltd., Osaka Umeda Twin Towers South,1-13-1 Umeda, Kita-ku, Osaka 530-0001, Japan.
⁵ Institute of Industrial Nanomaterials, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.
⁶ International Research Organization for Advanced Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.

Abstract

The production of textile products is increasing annually, and most of them are disposed of after use without recycling. One of the reasons for the low recycling percentage of discarded textile products is the difficulty of recycling as a single material as these products are produced from a combination of two or more materials. Therefore, a technology to separate materials is necessary to improve the recycling percentage of textile products and to build a sustainable recycling industry. The aim of this study was to separate the most common combination of materials, such as cotton/polyester, in an environmentally friendly technique using hydrothermal treatment with only water. Herein, the optimal treatment conditions for blended fabrics in a high-pressure reactor were studied. Moreover, cotton could be separated by treating the fabrics at 220 to 230 °C for 10 min while maintaining the shape of the fabrics. Additionally, polyester showed a melting point, confirming that polyester could be separated without decomposition into monomers, unlike common chemical recycling. The strength of the separated cotton and the molecular weight of the polyester were evaluated, and a kinetic analysis of the changes due to the treatment was conducted. The activation energy obtained from the Arrhenius plot was 111.8 kJ/mol for PET, which was smaller than 142.6 kJ/mol for cotton. This indicates that the decrease in the molecular weight of PET is more likely to occur than the change in the strength of cotton, suggesting the possibility of separating the materials from the kinetic analysis.