Using TEMPO oxidation to tailor deacetylation of carboxyl beta-chitin nanofibers from squid pen

Key Words:MEDIATED OXIDATION; CHITOSAN; ACID

Abstract:2,2,6,6-tetramethylpiperidine-1-oxyl-radical (TEMPO) oxidation is a classical method to obtain carboxyl chitin nanomaterials, but when the traditional TEMPO/NaBr/NaClO (TBN) oxidation system was oxidizing beta-chitin, it was only suitable for beta-chitin with a degree of deacetylation (DD) of 1%. Herein, the high yield carboxyl beta-chitin nanofibers (CO-ChNFs) were successfully prepared from squid pen beta-chitin with partially deacetylated (DD: 5-30%) using the TEMPO/NaClO/NaClO2 (TNN) oxidation system. The results show that the DD of purified beta-chitin has a great impact on the yield of CO-ChNFs, and the yield is as high as 98% when the DD of beta-chitin was 11%. XRD results showed that beta-chitin undergoes slight of beta-alpha transformation after TNN TEMPO oxidation, and the 010 crystal planes are arranged more closely. AFM characterization suggests that thus prepared CO-ChNFs have a diameter of 2-6 nm and a length in the micrometer range. The proposed preparation method breaks through the previous limitation of TEMPO oxidation for beta-chitin, and will facilitate the in-depth research and application of carboxyl beta-chitin nanofibers.

Volume:29

Issue:16

Translation or Not:no