• Journal of Microbiology and Biotechnology
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• v.25 no.6
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• pp.814-819
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• 2015

The natural crosslinking agent genipin has been applied widely in biomedicines and foods nowadays. Because of the special hemiacetal ring structure in its molecule, it can only be prepared by hydrolysis of geniposide according to biocatalysis. In this research, strategies including aqueous-organic biphasic catalysis and substrate fed-batch mode were adopted to improve the biocatalysis process of genipin. A 10 L ethyl acetate-aqueous biphasic system with geniposide fed-batch led to a satisfying genipin yield. With Fusarium solani ACCC 36223, 15.7 g/l genipin in the ethyl acetate phase was obtained, corresponding to space-time yields of 0.654 g l^-1 h^-1.

• Polymer(Korea)
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• v.35 no.1
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• pp.72-76
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• 2011

The physical properties of crosslinked poly(vinyl alcohol)(PVA) by natural dyes as crosslinking agents were investigated and a comparison was made with chemically crosslinked PVA by Polycup 172. It was found that natural anthocyanin and crocin made possible to crosslink PVA physically through the hydrogen bonding of OH in both PVA and natural dyes in the present with NaCl as a catalyst. The water swellability dramatically decreased and the physical crosslinking led to decreasing of crystallinity of PVA. The lowering of thermal stability was noticed in the physically crosslinked PVA compared to chemically crosslinked PVA due to its lower crosslink density. However even natural dyes have polysaccharides in their chain, their thermal stability was higher than uncrosslinked PVA.

• Textile Coloration and Finishing
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• v.2 no.2
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• pp.14-19
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• 1990

The setting behavior of disulfide-enriched wool and disulfide-crosslinked silk obtained by treatment with a disulfide-containing crosslinking agent, bis $(\beta-isocyanatoethyl)$ dissulfide was compared with that of untreated wool and silk under the absence and the presence of a reducing agent. Rearrangment of secondary bonds facilitated by cleavage of crosslinks as well as rearrangement of crosslinks itself seems to play an important role in the set stability.

• Fashion & Textile Research Journal
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• v.10 no.2
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• pp.260-266
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• 2008

Recently there has been a growing interest in the use of natural dyes in textile applications. Natural dyes can exhibit better biodegradability and generally have a higher compatibility with the environment. In this study, the colorants of clove were extracted with boiling water. Chitosan crosslinked cotton fabrics have been dyed with aqueous extract of clove and their dyeabilities on the fabrics were studied. Additionally the fastness to washing and light, and the effects on antimicrobial properties were also investigated. Cotton fabrics were treated with a crosslinking agent epichlorohydrin in the presence of chitosan to provide the cotton fabrics the dyeing properties of natural dye(clove) by the chemical linking of chitosan to the cellulose structure. This process was applied by means of the conventional mercerizing process. The chitosan finishing and durable press finishing of the cotton fabrics occurred simultaneously in the mercerization bath. The dyeability(K/S), which was obtained by CCM observation, remarkablely became increased when the crosslinked chitosan concentration was higher. The hue value indicated reddish yellow with increasing the crosslinked chitosan concentration. And the color fastness to washing and light was the almost the same. The chitosan treated cotton fabrics showed very high activities with almost 100% reduction.

• Textile Coloration and Finishing
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• v.20 no.3
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• pp.8-17
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• 2008

For the purpose of standardization and practicability of natural dyeing, the mordanting and dyeing properties of turmeric was studied. In this study, the colorants of turmeric were extracted with boiling water. Chitosan-crosslinked cotton fabrics was dyed with aqueous extract of turmeric and their dyeabilities on the fabrics were studied. Additionally the fastness to washing and light were also investigated. Cotton fabrics were treated with a crosslinking agent epichlorohydrin in the presence of chitosan to provide the cotton fabrics the dyeing properties of natural dye(turmeric) by the chemical linking of chitosan to the cellulose structure. The chitosan finishing and durable press finishing of the cotton fabrics occurred simultaneously in the mercerization bath. The dyeability(K/S), which was obtained by CCM observation, remarkably became increased when the crosslinked chitosan concentration was higher. Dyeability of turmeric was improved on chitosan-crosslinked cotton fabric rather than only cotton fabric, while the saturated dyeing time was 20minutes at $60^{\circ}C$. The hue value indicated greenish yellow with increasing the crosslinked chitosan concentration. And the color fastness to washing and light was almost the same.

• Elastomers and Composites
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• v.35 no.4
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• pp.303-310
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• 2000

Low temperature retraction characteristics were investigated on the cured natural rubber with various ratios of crosslinking agents, filler and additives. The cured natural rubber product was elongated about 200% at $-40^{\circ}C$ for 24 hours and then retracted. In a definite range, the retraction was increased as the sulfur to accelerator ratio increased and as the filler contents decreased. The retraction was maximum for a definite range of amount of accelerators, plasticizer and activator. Adding some peroxide additively retraction characteristics improved and curing time got longer.

• Fashion & Textile Research Journal
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• v.10 no.3
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• pp.377-384
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• 2008

For the purpose of standardization and practicability of natural dyeing, the mordanting and dyeing properties of gallnut was studied. In this study, the colorants of gallnut were extracted with boiling water. Chitosan crosslinked cotton fabrics were been dyed with aqueous extract of gallnut and their dyeabilities on the fabrics were studied. Additionally, the fastness to washing and light were also investigated. Cotton fabrics were treated with a crosslinking agent epichlorohydrin in the presence of chitosan to provide the cotton fabrics the dyeing properties of natural dye(gallnut) by the chemical linking of chitosan to the cellulose structure. The chitosan finishing and durable press finishing of the cotton fabrics carried out simultaneously in the mercerization bath. The dyeability(K/S), which was obtained by CCM observation, remarkably increased as the concentration of chitosan was high. Dye ability of gallnut showed higher toward chitosan treated cotton than controlled cotton fabric under condition at $60^{\circ}C$, for 20 min. The hue value indicated reddish yellow with increasing the crosslinked chitosan concentration. And the color fastness to washing and light was the almost the same.

• Journal of the Korean Applied Science and Technology
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• v.29 no.1
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• pp.13-18
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• 2012

A die casting mold releasing agent was prepared from aqueous mixture of powdery carbon black and water soluble natural polymeric materials such as xanthan gum(X-gum) and carboxymethyl cellulose(CMC), which were used as thickening agent as well as curing agent with aldehydes. The suitable concentration of natural polymers for stable dispersion of carbon black in water was 0.25 wt% of X-gum or 1.0 wt% of CMC. When CMC was used less than 1 wt%, the final carbon black disperion showed a rapid phase separation. The adhesion of carbon black releasing agent on glass plate was improved with the amount of crosslinking agent, glutaraldehyde and chain extender, oligosaccharide. However, the affinity of carbon black releasing agent prepared with X-gum was stronger than that with CMC on glass plate. The final carbon black mold releasing agents prepared under our mixing conditions can be applied to the production of castings of high quality with good workability and without worthening evironmental situations.

• Journal of Adhesion and Interface
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• v.9 no.2
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• pp.8-15
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• 2008

Microcapsules have been widely used in cosmetics and pharmacology as controlled delivery devices of various active materials. Chitosan is the second most plentiful natural biopolymer with biocompatibility and nontoxicity. The chitosan microcapsules were prepared by the water-in-oil (W/O) emulsion method using glutaraldehyde as a crosslinking agent. Span80 was used as an emulsifier, and mineral oil was used as a medium material. Perfectly spherical microcapsules were obtained in the size range of $2{\sim}10{\mu}m$. The effects of emulsifier concentration and stirring speed on the average particle size and distribution were investigated. Encapsulation and release behavior of the microcapsules with different amount of the crosslinking agent (glutaraldehyde), different chitosan contents and different emulsifier concentration conditions were also investigated. The release rate of riboflavin was controlled by the crosslinking density of the chitosan and amount of emulsifier in the preparation of the microcapsule.

• Journal of Chest Surgery
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• v.44 no.3
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• pp.197-207
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• 2011

Background: In cardiac surgery, especially in the reconstruction of vascular structures and intracardiac defects, glutaraldehyde has usually been used as the reagent for fixing porcine or bovine pericardial tissues. But the well-known problem of calcification or cytotoxicity of glutaraldehyde motivates the search for a replacement. The aim of this study is to investigate the physical, mechanical, and biochemical characteristics of bovine pericardial tissues fixed with genipin, which is known to be a less toxic and more natural fixing reagent. Materials and Methods: Bovine pericardial tissues were fixed with different concentrations and conditions of glutaraldehyde and genipin. To determine the physical, mechanical, and biochemical differences among different concentrations and conditions, we divided the tissue into 18 groups by concentration, the addition of organic solvents, and the timing of adding the organic solvents, and compared the characteristics of each group. Results: Tensile strength, physical activity, and thermal stability tests revealed that the tissues fixed with glutaraldehyde were better with regard to mechanical strength and biochemical durability. However, the difference was not significant statistically. Conclusion: Genipin can be used as an alternative crosslinking agent for pericardial tissue, considering given its physical, mechanical, biochemical characteristics and low cytotoxicity comparable to glutaraldehyde. However, further studies are needed on the immune reaction and the long term changes in genipin-fixed tissues in the human body.