Effect of the degree of acetylation on the physicochemical properties of α-chitin nanofibers.

The effective utilization of abundant α-chitin resources for materials engineering applications requires methods for controlling the physicochemical properties of α-chitin nanofiber (NF) dispersions. Herein, the relationship between the degree of acetylation (DA) of α-chitin and the physicochemical properties of α-chitin nanofibers (α-ChNFs) was investigated. α-Chitin with different DAs was prepared by varying the deacetylation treatment time.

Non-catalytic conversion of chitin into Chromogen I in high-temperature water.

The non-catalytic conversion of chitin into N-acetyl-ᴅ-glucosamine (GlcNAc) derivatives such as 2-acetamido-2,3-dideoxy-ᴅ-erythro-hex-2-enofuranose (Chromogen I) was investigated in high-temperature water at 290-390 °C and 25 MPa with a reaction time of 0-180 min. High-temperature water treatment is a promising method for chitin conversion as it does not require the use of any additional organic solvents or ionic liquids. A semi-batch reactor was developed to control the reaction temperature and time.

Preparation of β-chitin nanofiber aerogels by lyophilization.

In this study, chitin nanofiber dispersions prepared in neutral and acidic pH conditions were lyophilized to produce aerogels. The effects of the freezing speed of the nanofiber dispersions and the dispersibility of the chitin nanofiber were studied. The characteristics of the aerogels were studied using scanning electron microscopy, relative surface area measurements, and compression tests.

Self-Sustaining Cellulose Nanofiber Hydrogel Produced by Hydrothermal Gelation without Additives.

We prepared a self-sustaining hydrogel from 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibers (TOCNs) via hydrothermal treatment at 160 °C. The self-sustaining hydrogels could be obtained at less than 1 wt % TOCNs without any additives. Brownish hydrogels obtained after the hydrothermal treatment could be rendered transparent by immersing them in distilled water at 5 °C.

Systematic dynamic viscoelasticity measurements for chitin nanofibers prepared with various concentrations, disintegration times, acidities, and crystalline structures.

Dynamic viscoelasticities were measured for chitin nanofiber (ChNF) dispersions prepared with various concentrations, disintegration times, acidities, and crystalline structures. The 0.05w/v% dispersions of pH neutral ChNFs continuously exhibited elastic behavior.

Effect of acidity on the physicochemical properties of α- and β-chitin nanofibers.

We have investigated whether acidity can be used to control the physicochemical properties of chitin nanofibers (ChNFs). In this study, we define acidity as the molar ratio of dissociated protons from the acid to the amino groups in the raw chitin powder. The effect of acidity on the physicochemical properties of α- and β-ChNFs was compared.

Effect of purification method of β-chitin from squid pen on the properties of β-chitin nanofibers.

The relationship between purification methods of β-chitin from squid pen and the physicochemical properties of β-chitin nanofibers (NFs) were investigated. Two types of β-chitin were prepared, with β-chitin (a→b) subjected to acid treatment for decalcification and then base treatment for deproteinization, while β-chitin (b→a) was treated in the opposite order. These β-chitins were disintegrated into NFs using wet pulverization.