A novel cascade organosolv degumming method for preparation of hemp fibers using glycolic acid and ethanolamine

In an attempt to implement eco-friendly degumming for preparation of hemp fibers. This study developed a cascade organosolv degumming method employing the advantages of both organic acids and organic bases without using any inorganic alkaline reagents. Compared with the degumming process using only glycolic acid (GA) or ethanolamine (ETA), the cascade degumming improved the hemicellulose and lignin removal rates by 20.1% and 139.8%, respectively, under low temperature and short reaction time. Moreover, this work reduced the GA concentration from 20–10%. The FTIR result showed that GA mainly acted on removal of G-type lignin, while ETA mostly removed S-type lignin. In addition, the FTIR and solid-state 13 C NMR results showed that the esterification induced by GA was eliminated by ETA in the cascade degumming process. Although the hemp fibers of the cascade degumming exhibited slightly lower tensile strength, the cascade degumming contributed to finer hemp fiber diameter (10.09 dtex) than the alkaline degummed fibers (12.66 dtex). Thus, the cascade degumming has favorable effects in removing gum components and achieving better fiber separation.