• Macromolecular Research
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• 제16권6호
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• pp.492-502
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• 2008

This study examined the adsorption of a synthetic cutting fluid and cutting fluid effluent on chitosan and SDS-modified chitosan, Chitosan and SDS-modified chitosan were prepared in form of beads and fibers. A series of batch experiments were carried out as a function of the initial concentration of cutting fluid, contact time and pH of the fluid. The contact angle study suggested that the SDS-modified chitosan was more hydrophobic than chitosan. The Zeta potential study showed that chitosan, SDS-modified chitosan and synthetic cutting fluid had a point of zero charge (PZC) at pH 7.8, 9 and 3.2, respectively. SDS-modified chitosan has a greater adsorption capacity than chitosan. The experimental results show that adsorption capacity of the cutting fluid on 1.0 g of SDS-modified chitosan at pH 3 and for a contact time of 120 min was approximately 2,500 g/kg. The adsorption capacity of chitosan and SDS-modified chitosan increased with decreasing pH. The Langmuir, Freundlich, and Brunauer Emmett and Teller (BET) adsorption models were used to explain the adsorption isotherm. The Langmuir isotherm fitted well with the experimental data of chitosan while the BET isotherm fitted well with the SDS-modified chitosan data. Pseudo first- and second-order kinetic models and intraparticle diffusion model were used to examine the kinetic data. The experimental data was fitted well to a pseudo second-order kinetic model. The significant uptake of cutting fluid on chitosan and SDS-modified chitosan were demonstrated by FT-IR spectroscopy, SEM and heat of combustion.

• Weed & Turfgrass Science
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• 제3권1호
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• pp.19-28
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• 2014

본 연구는 유기질 토양개량재(SOA, soil organic amendment)에서 폴리머(WSP, water-swelling polymer), 칼슘, 펄라이트 및 키토산 성분이 켄터키 블루그래스의 생장에 미치는 영향을 조사함으로 공원, 잔디구장 및 골프장 조성 시 이들 소재를 이용한 혼합개량재를 실무에 활용할 수 있는 기초자료를 얻기 위해 수행하였다. 전체 24개 처리구는 SOA 유기질개량재에 WSP 중합체, 칼슘, 펄라이트 및 키토산을 이용하여 준비하였다. 온실에서 자란 켄터키 블루그래스에서 WSP 중합체, 칼슘, 펄라이트 및 키토산 성분에 따른 잔디생존력, 피복율, 잔디밀도 및 지상부 생장을 조사한 결과 유의한 차이가 나타났다. 파종후 1주 간격으로 조사한 발아율, 잔디밀도 및 초장은 이들 성분에 따라서 경시적인 변화가 크게 나타났다. SOA 유기물개량재에서 피복율 및 잔디밀도에 대한 폴리머 효과는 WSP 중합체 혼합비율이 0~3% 사이가 적절한 것으로 판단되었다. 하지만 생존력 및 엽 생장의 경우 WSP 중합체 혼합비율은 0~6% 사이가 적절하였다. 그리고 SOA 유기질개량재에 혼합한 칼슘, 펄라이트 및 키토산 성분 중 칼슘 및 펄라이트가 일반적으로 켄터키 블루그래스의 생장에 효과적이었으며, 키토산은 효과가 거의 없는 것으로 나타났다. 켄터키 블루그래스의 생존력에 가장 효과적인 성분은 칼슘이었고, 반면 잔디밀도는 펄라이트 성분이 가장 효과적이었다. 그리고 키토산 성분은 생존력 및 잔디밀도에 거의 효과가 없는 것으로 나타났다. 켄터키 블루그래스의 지상부 엽 생장에 대한 효과는 펄라이트 > 칼슘 > 키토산 성분 순으로 나타났다. 특히 키토산 성분은 초기 발아효과는 빠르게 나타났지만, 지상부 엽 생장은 파종 3주까지 전혀 나타나지 않았다. 본 연구를 통해 나타난 이러한 결과는 향후 실무에서 식재층 지반 조성 시 적용할 수 있는 모래+토양개량재 혼합구 조건에서 추가 생육검정 실험을 통해 이들 성분을 이용한 토양개량재의 개발 및 실무 응용에 활용하는 것이 바람직하고 판단되었다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1998년도 봄 학술발표회 논문집
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• pp.329-333
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• 1998

The major classes of antimicrobial agents for textiles include organo-metallics, phenols, quaternary ammonium salts, and organo-silicones. These finishes should be durable, have selective activity towards undesirable organisms, be compatible with other finishes and dyes, and be nontoxic to man [1]. Chitosan, as a deacetylated derivative of chitin, is a natural, non-toxic and biodegradable polymer. Chitosan is also known as an antimicrobial polysaccharide due to antimicrobial action of the amino group at the C-2 position of the glucosamine residue.(omitted)

• 폴리머
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• 제39권3호
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• pp.480-486
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• 2015

조직과 장기 유착은 외과적 수술 후 부작용으로 자주 발생된다. 이러한 조직 유착을 방지하기 위하여 유착부위에 장벽을 형성하여 장기 유착을 방지할 수 있는 온도감응성 하이드로젤 유착방지제를 제조하고자 하였다. 폴록사머, 키토산과 표피성장인자를 가지고 온도감응성 키토산 하이드로젤을 제조하였다. 제조한 키토산 하이드로젤은 인체 내 온도와 유사한 $35^{\circ}C$에서 졸-젤 전이현상을 보였고, 1분 이내에 빠르게 젤화되었다. 키토산 하이드로젤은 표피성장인자를 7일 동안 천천히 방출하였고, 마우스모델에서 평가한 결과 조직 유착 방지를 효과적으로 하는 것을 확인하였다. 온도 감응성과 항균성을 갖는 키토산 하이드로젤이 장기 부착의 증가와 표피성장인자를 천천히 방출하는 유착방지제로서 유용하게 사용될 수 있다.

• Korea-Australia Rheology Journal
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• 제12권3_4호
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• pp.175-179
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• 2000

Rheological properties of chitosan solutions were investigated as a function of polymer concentration. The viscosity curves for chitosan solutions consisted of two distinct viscosity regions, the Newtonian zero-shear viscosity (η$_{0}$) region and the shear rate dependent apparent viscosity (η$_{app}$) region. The shear rate dependence of viscosity was more clearly observed at higher chitosan concentrations. The critical coil overlap parameter (C＊〔η〕) was determined to be approximately 3.2 from a plot of zero-shear specific viscosity η$_{sp,0}$ vs coil overlap parameter (C〔η〕), which was lower than C〔η〕4.0 reported for other random coil polysaccharides. It was also found that the slope of η$_{sp,0}$ vs C〔η〕 was 3.9 at concentrated C〔η〕>C＊〔η〕domain, while 1.2 at dilute C〔η〕$_{0}$ ${\gamma}$/${\gamma}$$_{0.8}$ relation.ion.n.n.

• Macromolecular Research
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• 제14권4호
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• pp.461-465
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• 2006

Two types of injectable system using thermosensitive chitosan (chitosan-g-NIPAAm), hydrogel and microparticles (MPs)-embedded hydrogel were developed as drug carriers for controlled release and their pharmaceutical potentials were investigated. 5-Fluorouracil (5-FU)-loaded, biodegradable PLGA MPs were prepared by a double emulsion method and then simply mixed with an aqueous solution of thermosensitive chitosan at room temperature. All 5-FU release rates from the hydrogel matrix were faster than bovine serum albumin (BSA), possibly due to the difference in the molecular weight of the drugs. The 5-FU release profile from MPs-embedded hydrogel was shown to reduce the burst effect and exhibit nearly zero-order release behavior from the beginning of each initial stage. Thus, these MPs-embedded hydrogels, as well as thermosensitive chitosan hydrogel, have promising potential as an injectable drug carrier for pharmaceutical applications.

• Bulletin of the Korean Chemical Society
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• 제34권8호
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• pp.2441-2445
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• 2013

Chitosan non-woven fabrics were acetylated to improve their antimicrobial properties. The active chlorine content, antimicrobial properties, storage stability, and surface properties of acetylated chitosan non-woven fabrics were investigated. The active chlorine content of the fabrics increased upon reduction of the degree of the acetylation or increase in sodium hypochlorite concentration. Acetylated chitosan non-woven fabrics showed powerful antimicrobial activity by efficiently killing Escherichia coli and forming a growth inhibition zone for Staphylococcus aureus. Furthermore, scanning electron microscopy observations demonstrated that the acetylated chitosan non-woven fabrics were not damaged in sodium hypochlorite solution.

• 방사선산업학회지
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• 제7권1호
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• pp.51-54
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• 2013

Chitosan is a useful natural polymer material in many application fields such as biomaterials, water-treatment, agriculture, medication, and food science. However, the poor solubility limits its application. In this study, the effects of radiation on chitosan were investigated using gamma ray and electron beam irradiation. The chemical structure and molecular weight analysis show similar degradation effects of chitosan powder in both gamma ray and electron beam irradiation. However, the radiation irradiated chitosan in $H_2O$ has a lower molecular weight, since the hydroxyl radicals attack the glycosidic bonds. This effect is more clearly shown in the electron beam irradiation results.

• Bulletin of the Korean Chemical Society
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• 제24권9호
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• pp.1303-1307
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• 2003

The low molecular water-soluble chitosan nanoparticles (LMWSC-NPs) were prepared, which was modified with hydrophilic and hydrophobic moieties to evaluate the potential for pharmaceutics application. The synthesis of LMWSC-NPs was identified by FT-IR and $^1H$-NMR spectra. Also, we measured the photon correlation spectroscopy (PCS), transmission electron microscope (TEM) and atomic force microscope (AFM) to investigate the characteristics and morphology of the LMWSC-NPs. At the PCS measurement, the more increase the number of substitutive group, the more decrease the positive charge of LMWSC-NP surface. From the results of TEM and AFM, spherical morphologies were observed, and their sizes were 30-150 nm. Resultantly, LMWSC-NPs prepared in this experiment will be expected as a suitable device for the drug targeting system.

• Journal of Pharmaceutical Investigation
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• 제31권4호
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• pp.233-239
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• 2001

Local drug delivery by using biocompatible polymers has been developed in the treatment of periodontitis for many years. In the field of dental therapy, doxycycline is usually a first choice because of its broad-spectrum antibiotic activity. The strip releases antibiotics for a week, and the polymer should be degradable after a week. In this study, we prepared and evaluated the chitosan strips and nanoparticle strips containing doxycycline hydrochloride, and studied their antiacterial activity, dissoultion, and degrability in vitro. The weight of cast strip containing a 5 mg of doxycycline hydrochloride and a 45 mg of chitosan polymer was $57.67{\pm}0.17\;mg$. The release rate of doxycycline hydrochloride from the strip was measured by HPLC. The drug released from chitosan strip and nanoparticle strip was shown to be $50\;{\mu}g/mL$ in first 24 hours. In antibacterial test showed growth inhibitory activity after 24 hrs anaerobic incubation. In vitro degradability showed demolished weight of $93.74{\pm}0.08%$ chitosan strip, $82.48{\pm}1.29%$ chitosan nanoparticle strip, $2.47{\pm}1.99%$ polycarprolactione strip (control). These results showed that, with this doxycycline hydrochloride strip, it is feasible to obtain a sustained release of the drug within the periodontal pocket for seven days which may be improve for local drug delivery system for treatment of periodontal disease.