Fibers, chitin/chitosan

Imoto, Y, Ichikawa, N., Chirachanchai, S. and Rartwatanaseii, T. (2009) Chitin/chitosan fiber-reinforced diene rubber compositions, their manufacture, and pneumatic tires using the compositions. Jpn. Kokai Tokkyo Koho, JP 2009001671 A 20090108. 

Keywords Blends Chitin Chitosan Fibers Hydrogels Tissue engineering Wound dressing... 

Contrary to chitin, chitosan is a relatively soluble biopolymer. The solution properties of a chitosan depend on its average DD and the distribution of the acetyl gronps along the main chain [146]. Various solvents and processes for spinning chitosan fibers have been developed [138, 147, 148]. In recent years, chitin/chitosan fiber spinning process and their novel applications have been continnously studied. 

We used the crosslinked chitosan fiber (hereafter called ChF) in this experimental study. ChF was fabricated by Fuji Spinning Co., Japan. Fig.l shows the unit molecular structure of chitosan which was transformed from chitin by deacetylation. Chitin is a natural biopolymer which is contained in the shell of arthropods. Chitosan was crosslinked to make an adsorbent with acid, alkaline, and chemical proofs. The fabrication method of ChF was presented elsewhere.[S,6]. 

USE Deacylated chitin, chitosan, used in water treatment in photographic emulsions in improving the dyeability of synthetic fibers and fabrics. 

The molecular weight of chitosan is another important property that determines its suitability for a particular application. It determines the viscosity of its solution and the strength of chitosan fiber and film. The molecular weight of chitin and chitosan depends on its source and deacetylation conditions [time, temperature, and concentration of NaOH], respectively [1, 4]. Molecular weight of chitosan determined by various methods such as viscometry [28], gel permeation chromatography [29] and light scattering spectrophotometry [30]. 

Tokura, S. and Nishi, N. (1982) Preparation and properties of alkyl-chitin fibers, in Chitin Chitosan (eds S. Hirano and S. Tokura), Proceedings of the Second International Conference on Chitin and Chitosan, Japanese Society of Chitin Chitosan, Tattori, Japan, pp. 244-247. 

Masuda, M. and Yokota, N. (2006) Mixture yarns for clothing with antibacterial properties and tender handle, comprising yarns containing chitin fibers or chitosan fibers and antibacterial woven and knitted fabrics therefrom. Jpn. Kokai Tokkyo Koho, JP 2006225785 A 20060831. 

FIGURE 20.2 Changing of blood pressure by intake of high salts and dietary fibers in rats, o, , normotensive rats a, a, SHRSP o, a, alginic acid diet , a, chitosan diet. (From Okuda, H. et al., J. Chitin Chitosan, 2, 49, 1997.)... 

Hypercholesterolemia is an important risk factor for cardiovascular disease. The hypocholester-olemic action of chitosan can be explained to be due to the decrease in cholesterol absorption and interference with bile acid absorption, a mechanism similar to those of dietary fiber constituents. Here, the cholesterol-lowering effects of chitin, chitosan, and their derivates are reported based on animal and clinical studies. 

Agboh OC, Qin Y (1997) Chitin and chitosan fibers. Polym Adv Technol 8 355-365... 

Agboh, O. C. and Quin, Y. (1997). Chitin and chitosan fibers. Advances in polymer technology 8, 355. 

Other researchers in addition to Hirano have extensively studied the production of various chitin, chitosan, their derivatives, and composite fibers with other polymer materials, since 1994. Their spinning solution, coagulating solution, and polymer materials used in the dope are summarized in Table 12.3. Rathke and Hudson s review concerning chitin, chitosan, and their derivatives covers all of the reported information up to 1994 [24]. 

Mechanical properties of chitin, chitosan, and their derivatives are reported up to 1994 in Rathke and Hudson s review paper [24]. Table 12.4 shows the mechaiucal properties of various fibers based on chitin and chitosan obtained between 1994 and 2004. 

Chitosan is called the last biomass of the twentieth century, and is a material that waits further development as an extraordinary biomaterial in the twenty-first century. Chitin and chitosan, derived from shellfish waste, continue to be underutilized resources. We believe that to further their development as a resource, that there are needs for products of intermediate value easy to produce and which capitalize upon the unique features of chitin and chitosan. Fibers and films based on chitin or chitosan have considerable promise for medical textile applications. The commercialization of chitosan-based hemostatic bandages, such as Hemcon , represents a significant accomplishment in gaining the acceptance of chitosan as a biomaterial. 

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