One-Step Preparation of Chitin Nanofiber Dispersion in Full pH Surroundings Using Recyclable Solid Oxalic Acid and Evaluation of Redispersed Performance.

This study proposed an efficient and economical preparation pathway from purified chitin to nanofibers that can be dispersed in full pH surroundings. Recyclable oxalic acid was applied to prepare chitin nanofibers in a mild environment along with concurrent modifications of the carboxylic groups on the surface. Pretreatment with oxalic acid significantly improved the mechanical disintegration of chitin into nanofibers, the length of nanofibers reached ∼1100 nm, and the crystallinity and thermal stability of the chitin were basically unchanged with mild treatment. Oxalic acid can be reused many times with a high recovery of over 91%. Most importantly, the obtained nanofibers can be fabricated into films and hydrogels with certain mechanical properties, which can be redispersed into nanofibers using mild mechanical treatment. This method not only produces nanofibers in a green, reusable system but also provides a reference for the potential application of chitin nanofibers in commercial transportation and wide applicability.