Preparation and Grafting Functionalization of Self-Assembled Chitin Nanofiber Film

Jun-Ichi Kadokawa

doi:10.3390/coatings6030027

Abstract

Chitin is a representative biomass resource comparable to cellulose. Although considerable efforts have been devoted to extend novel applications to chitin, lack of solubility in water and common organic solvents causes difficulties in improving its processability and functionality. Ionic liquids have paid much attention as solvents for polysaccharides. However, little has been reported regarding the dissolution of chitin with ionic liquids. The author found that an ionic liquid, 1-allyl-3-methylimidazolium bromide (AMIMBr), dissolved chitin in concentrations up to ~4.8 wt % and the higher contents of chitin with AMIMBr gave ion gels. When the ion gel was soaked in methanol for the regeneration of chitin, followed by sonication, a chitin nanofiber dispersion was obtained. Filtration of the dispersion was subsequently carried out to give a chitin nanofiber film. A chitin nanofiber/poly(vinyl alcohol) composite film was also obtained by co-regeneration approach. Chitin nanofiber-graft-synthetic polymer composite films were successfully prepared by surface-initiated graft polymerization technique. For example, the preparation of chitin nanofiber-graft-biodegradable polyester composite film was achieved by surface-initiated graft polymerization from the chitin nanofiber film. The similar procedure also gave chitin nanofiber-graft-polypeptide composite film. The surface-initiated graft atom transfer radical polymerization was conducted from a chitin macroinitiator film derived from the chitin nanofiber film.

Highlights

Polysaccharides are widely distributed in nature and exhibit important functions such as structural materials and energy providers [1,2]
Chitin is still an unutilized biomass resource primary because of highly crystalline and bulk structure owing to numerous intra- and intermolecular hydrogen bonds, which cause the limitation of solubility with solvents [7]
In 2002, an Ionic liquids (ILs), 1-butyl-3-methylimidazolium methylimidazolium chloride (BMIMCl, Figure 3), was found to dissolve cellulose in relatively high concentrations and this3),research opened up a cellulose new wayin for the development of a class chloride

Summary

Introduction

Polysaccharides are widely distributed in nature and exhibit important functions such as structural materials and energy providers [1,2]. The cellulose dissolution with IL-type solvents, it was considered to be of little practical value at the time because the concept of ILs had not been put forward. Figure was found to dissolve cellulose in relatively high time because the concept of ILs (BMIMCl, had not been put 3), forward. In 2002, an IL, 1-butyl-3-methylimidazolium methylimidazolium chloride (BMIMCl, Figure 3), was found to dissolve cellulose in relatively high concentrations and this3),research opened up a cellulose new wayin for the development of a class chloride Figure was found to dissolve relatively high concentrations andof this concentrations and this research opened up a new way for the development of a class of polysaccharide solvent systems [21]. Twothe types ILs, i.e., 1‐allyl‐3‐methylimidazolium bromide (AMIMBr, Figure 3) and some imidazolium dissolution of chitin with.

Representative

Preparation

Surface-initiated

10. Stress‐strain

Conclusions