Superfine Grinding Induced Amorphization and Increased Solubility of α-Chitin

Abstract As the most common structure of chitin, α-chitin is insoluble in common aquatic and organic solvents, and is very difficult to be processed due to its highly ordered crystalline structure and the large number of intermolecular and intramolecular hydrogen bonds. Amorphization of α-chitin has been proved to be a valid measure for improving its subsequent functionalization efficiency and depolymerization yield. In this study, superfine grinding (SFG) was introduced to make α-chitin amorphous, and it was found that SFG effectively reduced the particle size, changed the microstructure, and significantly reduced the crystallinity of α-chitin. Chitin with crystallinity as low as 8.39% was obtained after 60 min of SFG treatment, and the amorphous chitin became readily dissolved in 10% NaOH solution after one round of freezing-thawing process. As continuous manner could be employed, SFG might be a powerful and efficient method for preparing amorphous chitin to help its processing and modification of various applications.