• Macromolecular Research
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• v.12 no.5
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• pp.466-473
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• 2004

We have used FT-IR spectra to explain the effects of hydrogen bonding between chitosan and polycaprolactam (PA6). A dynamic mechanical analysis study suggested that the optimum chitosan and PA6 miscibility under the conditions of this experiment were obtained at a blending ratio of 40:60. We studied the thermal degradation of chitosan blended with PA6 (chitosan/PA6) by thermogravimetric analysis and kinetic analysis (by the Ozawa method). Dry chitosan and PA6 exhibited a single stage of thermal degradation and chitosan/PA6 blends having> 20 wt% PA6 exhibited at least two stages of degradation. In chitosan/PA6 blends, chitosan underwent the first stage of thermal degradation; the second stage proceeded at a temperature lower than that of PA6, because the decomposition product of chitosan accelerated the degradation of PA6. The activation energies of the blends were between 130 and 165 kJ/mol, which are also lower than that of PA6.

• Korean Journal of Human Ecology
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• v.1 no.2
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• pp.119-128
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• 1998

Nonwoven fabrics for diaper coverstock were treated with chitosan solution by pad-dry method. Two chitosans of different molecular weigh(Mw) with similar degree of deacetylation(DDA) were used: Mw 1,800(chitosan oligomer, DDA 84%). Effect of chitosan treatment on the mechanical properties was investigated using KES-FB system. Primary hand values were calculated from mechanical properties using the same equation as the men's suiting equation with minor modification, and total hand values were calculated using new KN-5LNW equation for nonwoven fabrics developed by Kawabata et al. Increase in chitosan treatment concentration increased B, 2HB, WT, LT and RC, and decreased WC continuously. Chitosan treatment affected other mechanical properties regardless of molecular weight. Considering primary hand values obtained from mechanical properties, it was found that chitosan of Mw 180,000 and chitosan oligomer provided softer, smoother, and more bulky at below 0.05% and above 0.5% treatment concentration respectively. Samples treated with 1.0% chitosan oligomer solution, and 0.01％ chitosan solution of Mw 180,000 showed the best total hand values. (Korean J Human Ecology 1(2):119∼128, 1998)

• Journal of the Korean Home Economics Association
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• v.43 no.2
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• pp.115-126
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• 2005

Environmentally and human compatible chitosan were pretreated on cotton fabrics which were then dyed with 100% persimmon juice. The chitosan concentration was 1% and the chitosan types were high molecular weight chitosan (1980cps), low molecular weight chitosan (18첸), chitosan oligomer and water soluble chitosan. The properties of the fabric surfaces, the dyeabilities, the color fastnesses, the antibacterial activities, the strengths, the elongations and the drape stiffnesses were evaluated. The properties of the chitosanpretreated, persimmon juice-dyed cotton fabrics (CLP) were compared to those of the untreated (CN), chitosan treated (CL) and persimmon juice-dyed fabrics (CP). The results were as follows. The fibers extruded from the surface of CN decreased on CP. The air between the fibers within CN were substituted by chitosan solution or persimmon juiceand decreased within CLP according to SEM observations. The effects of chitosan treatment, the chitosan molecular weights and the degrees of deacetylation of chitosan on the dyeabilities of the persimmon juice-dyed cotton fabric were not distinct. The curing after chitosan padding improved the dyeabilities of CLP compare to noncuring. The strengths of CP decreased and those of CL increased, compared to those of CN. The strengths of CLP were greater than those of CP. The elogations of CP and CL were greater than those of CN. The strengths and elongations of CLP were greater than those of CN. The chitosan treatments improved the strengths but not the elongations. The drape stiffnesses of CL, CP and CLP were greater than those of CN. The antibacterial activites of chitosan pretreated, persimmon juice-dyed cotton fabrics against Staphylococcus aureus were increased by more than 98% by persimmon juice.

• Microbiology and Biotechnology Letters
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• v.26 no.4
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• pp.338-344
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• 1998

New type of chitosan derivatives, chitosan-g-MAP, were synthesized by graft copolymerization of mono (2-methacryloyl oxyethyl) acid phosphate (MAP) into chitosan, in order to solubilize chitosan in water. Ceric ammonium nitrate was used as an initiator for graft copolymerization. The optimal conditions for graft copolymerization were determined on the basis of reaction temperature, time, and the concentration of initiator and monomer. The reaction conditions for the highest percentage of grafting were as follows: an initiator concentration, 3.5${\times}$10$\^$-3/ M; monomer concentration, 0.19 M; and reaction temperature, 40$^{\circ}C$ The reaction rate reached the maximum value after 4 hrs of reaction. Antifungal activity was tested against Candida albicans, Trichophyton rubrum and Trichophyton violaceum by using chitosan-g-MAP and two other chitosan samples which have degree of deacetylation of 70% (DA-7) and 90% (DA-90). Their antifungal activities were investigated in weak acidic range. Maximum antifungal activity of them was observed at pH 5.75. Chitosan-g-MAP inhibited thoroughly the growth of Candida albicans and Trichophyton violaceum. Howerver, DA-70 and DA-90 showed higher antifungal activities on Trichophyton rubrum than that of chitosan-g-MAP.

• Journal of the Korean Home Economics Association
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• v.42 no.3
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• pp.145-158
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• 2004

Experimental conditions for evaluating chitosan antibacterial activities were established. The chitosan antibacterial activities were measured against the Staphylococcus aureus and evaluated for their application to antibacterial textile finishing. The strain of Staphylococcus aureus used in this experiments was KCTC 1916. The chitosan antibacterial activities were estimated from the bacterial densities or ％reduction of bacteria in chitosan solutions and bacterial culture mixtures after incubation under specific conditions. Six parameters as follows were evaluated to optimize the experimental conditions for measuring antibacterial activities. The different combinations of mixtures according to the different ratios of chitosan solutions to the bacterial cultures showed different antibacterial activities. However, the chitosan antibacterial activities could be evaluated by comparing the data obtained from the same combinations of mixtures. The solvent influence on the chitosan solution antibacterial activities could be eliminated using control solution containing the same concentration of acetic acid. The initial pH of the chitosan -bacterial mixtures also affected the chitosan antibacterial activity; at a higher pH, higher activity in terms of ％reduction of bacteria was observed. In case of the bacterial solution without either the acetic acid or chitosan, the initial pH of the solution did not significantly affect bacterial growth. The ％ reduction of bacteria increased when contact times of bacteria with chitosan in the chitosan -bacterial mixture were expended upto 24 hours. However, the chitosan antibacterial activities could be successfully evaluated at contact time 0 where the chitosan-bacterial mixture was plated immediately after mixing and incubated to measure the bacterial number to 24 hours. Evaluating ％reduction of bacteria in the test mixtures after incubation were not changed when the inoculated bacterial concentrations were 2.3${\times}$10$\^$0/ml to 2.3${\times}$10$\^$6/ml. The optimal range of incubation time of the petri-Dish after plating the chitosan-bacterial mixture was 24 to 72 hours depending on the antibacterial activities of the test solutions.

• Food Science of Animal Resources
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• v.24 no.1
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• pp.1-7
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• 2004

The effects of chitosan dipping treatments with different molecular weights on the meat quality of Hanwoo(Korean Cattle) beef during refrigerated storage were investigated. The beef(M. Semimembranosus) were dipped in 0.5% chitosan(in 1% acetic acid) with two different molecular weights(Mw=150 and 600 kDa) for 5 min and stored at $1^{\circ}C$(90% RH). The pH was significantly(p<0.05) higher in chitosan(600 kDa) group than in the other groups. The L＊ value for 3 days was significantly(p<0.05) higher in chitosan (600 kDa) group, but it was not significantly(p>0.05) different after 6 days. The a＊ value of day 0(before storage) was not significantly(p>0.05) different among the treatment groups, however the a＊ value of day 12 was significantly(p<0.05) higher in chitosan(150 kDa) group. The metmyoglobin(%) was significantly(p<0.05) lower in chitosan(600 kDa) group. The total bacterial counts of day 0(before storage) were significantly(p<0.05) lower in chitosan(600 kDa) group, but during storage, the chitosan(150 kDa) group was effective in antibacterial activity. The chitosan(l50 kDa) group had significantly(p<0.05) lower shear force than the other groups over time.

• 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.

• Journal of Nutrition and Health
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• v.30 no.7
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• pp.770-780
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• 1997

This study was performed to investigate the effect of chitosan and NOCC from different sources and of different molecular weights on lipid metabolism. Sprague-Dawley rats were blocked into 26 groups according to body weight, and were raised for 4 weeks. Cadmium chloride was given at the level of 0 or 400 ppm in diet. Various chitosan and NOCC sources were given at the level of 0%(w/w) of diet. Total serum cholesterol and serum triglyceride concentrations were little affected by chitosan and NOCC supplements. However, HDL-cholesterol concentration and HDL : total cholesterol ratio were increased , and liver lipid, cholesterol , and triglyceride concentration were decreased by chitosan and NOCC supplements. The cholesterol and lipid lowering activity depends on fiber sources(crab and shrimp); type (chitosan and NOCC); and molecular weight(low , medium , and high). Among cadmium-free groups, chitosan-fed groups showed greater activity than NOCC -fed groups in lowering cholesterol and lipid levels, and greater fecal excretion of lipids and bile acids. Crab chitosans were more effective in cholesterol and lipid lowering activity than shrimp chitosans. The group fed high molecular weight crab chitosan showed the highest fecal excretion of lipids and bile acids. This indicated that high molecular weight crab chitosan was most effective in interfering with cholesterol and lipid absorption.

• 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.

• Fashion & Textile Research Journal
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• v.5 no.5
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• pp.529-538
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• 2003

Chitosan should be satisfied a certain Mw range for the final application, Low molecular weight chitosan(LMWC) can be acquired by depolymerizing high molecular weight starting chitosan. Using $H_2O_2$ in depolymerizing chitosan is very effective and reproducible in controlling Mw of resulting LMWC. However, $H_2O_2$ can break glycoside linkage of chitosan and oxidize some $-NH_2$ groups in chitosan. It has been reported that decrease in DA(degree of deacetylation) of LMWC prepared by $H_2O_2$. However, any quantitative data of decrease in DA has not been reported yet. In this study, DA of initial chitosan and DA of $H_2O_2$ treated chitosan were measured and the change in DA of chitosan upon $H_2O_2$ treatment were investigated. Change in DA was very different upon $H_2O_2$ treatment condition. LMWC also showed DA change upon time passage. Pre-swelling treatment of initial chitosan and low ratio of $H_2O_2$/chitosan prevented a decrease in DA significantly. Yellowing of LMWC was detected upon time passage, however, decrease in DA was minimal (around 1%).