• The Research Journal of the Costume Culture
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• v.12 no.6 s.53
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• pp.999-1009
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• 2004

Chitin is a derived product from the shell of shrimp or crab. Chitosan, a deacetylated product of chitin, has widely been used in the biomedical sector, food industry, and textile industry. Chitosan exhibits fiber-forming property under certain conditions. Nonwoven fabrics made of chitosan fibers may have diverse applications in the industry. Previous studies have revealed that the dye uptake properties of natural dyestuffs improved by the chitosan pretreatment on the fabric specimens. In this case, fabric specimen is coated with acidic salt form of chitosan, which is different from the pure chitosan, since the coating process employes coating with the acidic solution of the chitosan and subesquent drying. In this study, chitosan nonwoven fabric samples were prepared from chitosan sample having deacetylation degree of $100\%$ and molecular weight of 650,000. Chitosan nonwoven fabrics maintain the form of $-NH_2$ end-group. These in turn exhibit higher dye uptake ability than the fabrics coated with chitosan acidic solutions do.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.2
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• pp.477-483
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• 1999

The effects of chitin and chitosan on the contents of plasma and liver lipids and the fecal excretion of neutral and acidic steroids were investigated in rats fed with atherogenic diet. Dietary chitin did not affect plasma total cholesterol, LDL cholesterol and HDL cholesterol, while chitosan diet de creased total cholesterol and LDL cholesterol. Plasma content of triglyceride was reduced signif icantly by chitin diet but not by chitosan. Increases in fecal weight were observed in rats fed with either chitin or chitosan, and the increase was greater with chitosan than with chitin. Dietary chitosan resulted in an increase of fecal excretion of neutral steroids without any changes in the excretion of acidic sterols. Putting the results together, dietary chitosan reduces plasma cholesterol probably due to the reduction of cholesterol absorption. The decrease in plasma triglyceride level by dietary chitin requires further research to understand the mechinism.

• Fashion & Textile Research Journal
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• v.8 no.5
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• pp.577-584
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• 2006

The binding of heavy metal ions onto cross-linked chitosan in dilute aqueous solution has been investigated as a function of pH (4.0 and 7.0), agitation period (10-180min) and concentration of various metal cations (5, 10, 50 and 100ppm). In order to obtain adsorbents that are insoluble and stable, and prevent the dissolution loss of chitosan into an acidic aqueous solution, chitosan flakes were cross-linked with epichlorohydrine (ECH) and its adsorption behavior was compared with that of the non cross-linked chitosan. An advantage of ECH is that it does not eliminate the cationic amine functional group of chitosan. In terms of adsorption ratio, the chitosan cross-linked at an ECH was inferior to original chitosan and was found that chitosan has a selectivity much remarkable than the cross-linked chitosan in low concentrated metal solutions. However, no significant decreases in the adsorption ratios were observed between the cross-linked ECH-chitosan and the non cross-linked chitosan concerning the adsorption of $Ni^{2+}$, $Co^{2+}$, $Pb^{2+}$ and $Zn^{2+}$ acidic solution.

• Korean Chemical Engineering Research
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• v.52 no.3
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• pp.355-359
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• 2014

Recently, many chemicals produced from renewable resources such as lignocellulosics, micro-algae and marine macro-algae, were introduced to chemical industry. Chitin/chitosan is secondly abundant feedstock on Earth. It is easily obtained from crusraceans' shells such as crab, shrimp and insects. In this work, we performed the acidic-hydrothermal hydrolysis to produce levulinic acid from chitosan using statistical approach. By design of response surface methodology, the effect of reaction temperature, catalyst amount, and reaction time and their reciprocal interactions were investigated. As a result, higher reaction temperature and catalyst amount increased the higher concentration of levulinic acid. However, reaction time did not caused large increase of levulinic acid after some reaction period. Levulinic acid of 2.7 g/L produced from chitosan in the optimized condition of reaction temperature of $175^{\circ}C$, sulfuric acid of 2.4% and reaction time of 40.7 min.

• Textile Coloration and Finishing
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• v.14 no.3
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• pp.26-33
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• 2002

Dyeing properties and crosslinking effect of bifunctional reactive dyes on chitosan fiber were investigated to improve the stability of chitosan fiber against the mild acidic solution and the wet processing. Chitosan fibers were crosslinked with epichlorohydrin for comparing purpose, and dyed with C. I. Reactive Red 194, C. I. Reactive Blue 50, and the reactive dye having two $\alpha$-bromoacrylamide groups at various concentrations. The initial dyeing rates of reactive dyes are rapid and chitosan fibers absorb the relatively large amount of dyes. The chitosan fibers dyed with these dyes show the low degree of swelling and the low solubility in 1 % acetic acid solution and also represent the higher thermal stability The reactive dye with two $\alpha$-bromoacrylamide groups shows higher crosslinking effect than other dyes.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.529-529
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• 2012

Dispersion of carbon nanotubes in biocompatible media are of particular interest for diverse biomedical and nanomedicine applications. Various biomolecules and biopolymers such as DNA, proteins, poly L-lysine, starch, gelatin, steroid biosurfactants, and chitosan have shown capability for the effective dispersion of carbon nanotubes in water. Chitosan has demonstrated capacity for effective dispersion of single-walled carbon nanotubes (SWCNTs) in acidic medium and it also showed tendency to preferentially disperse smaller diameter nanotubes. Chemical functionalizations of chitosan enable its solubility in neutral pH water by reducing the intra and inter molecular hydrogen bonding. Herein, we present a neutral pH water soluble chitosan derivative, chitosan-hydroxyphenyl acetamide (CHPA), obtained by functionalizing the amino groups of chitosan with 4-hydroxyphenyl acetic acid, as an efficient biocompatible dispersant for debundling and solubilization of SWNTs in neutral aqueous solutions. Various process conditions for individual dispersion of SWCNTs are analyzed based on optical absorption and Raman spectroscopy.

• Journal of Fashion Business
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• v.11 no.5
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• pp.51-63
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• 2007

Chitosan, a natural cationic macromolecular material, has been known for its moisturizing and healing effect due to the coating action based on strong ionic bonding when the chitosan is treated on hair strands. In this study, the acidic aqueous chitosan solution was prepared to treat healthy hair, and damaged hair due to bleaching, relatively thin hair and thick hair specimens. The chitosan treatment effect was reviewed by comparing spectrophotometric and mechanical characteristics of the chitosan treated and untreated specimens. Electrostatic voltage was somewhat reduced after the chitosan treatment. Smoothly coated surface was observed, in the SEM images, especially for damaged hair specimens. The values of breaking strength, which is one of the indicators of the internal characteristics of hair, was high in the case of chitosan treated samples. The values of elongation was also high in the case of chitosan treated samples, which proves the chitosan treatment effect. The friction force, one of the indicators of surface characteristics, was reduced for the case of chitosan treated samples.

• Microbiology and Biotechnology Letters
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• v.22 no.6
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• pp.643-645
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• 1994

Chitin and chitosan has been almost neglected until 1960s, although they are the second largest biomass on earth. Their major use were as a natural flocculant for waste-water treatment, and partially used in the areas of food, feed industry, cosmetics and medicine. Possible sources of chitin among biomass were tested, and antibacterial activity and viscosity-concentration relation- ship of diluted acidic solution were examined.

• Journal of Fashion Business
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• v.10 no.2
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• pp.18-26
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• 2006

In this study, the effects of chitosan pre-treatment on the mordanting effect and dyeability were investigated in the dyeing using Japanese pagoda tree. The chitosan treatment effects were evaluated mainly focused on the colors after dyeing of cotton and nylon fabrics which were treated with acidic aqueous solution of chitosan. In the case of chitosan untreated fabrics, the mordanting effects on the cotton and nylon were insignificant and the dyeability was very low. Regardless of the mordant types(Al, Sn, and Fe), the dyed fabrics exhibited almost identical yellowish colors. In the case of chitosan treated fabrics, dark colors were obtained compared to the case of chitosan untreated and ${\Delta}E$ values were increased significantly. In cotton fabrics, the most excellent result was obtained under the condition of unmordanted and chitosan treated fabrics. This verifies the fact that routin coloring matters establish direct linkages with the chitosan components, which exhibit cationic nature, easily. In nylon fabrics, the effects of mordanting treatment and chitosan treatment are so insignificant that the routin coloring matters are presumed to establish direct dyeing with the nylon molecular chains.

• Journal of Biomedical Engineering Research
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• v.10 no.1
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• pp.59-66
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• 1989

The Applicability of chitin or chitosan microsphere as means to achieve sustained release of p-aminosalicylic acid(PAS) has been examined. The microsphere of chitin or chitosan containing PAS were prepared by coacervation in acidic aqueous system in range of pH 2.0-4.0. The dissolution test of PAS from polymeric drug system was carried out in vitro test. The dissolution rate of PAS from the microsphere with chitin was significanthly lower than that from the microsphere with chitosan.The dissolution rate of PAS from the microsphere was decreased with increasing of concentration of chitin and chitosan. The sustained release of PAS from the microsphere was more effective at pH 1.2 than pH 6.8.