• Korea-Australia Rheology Journal
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• 제14권1호
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• pp.1-9
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• 2002

Steady and dynamic shear properties of two hydrophobically modified alkali soluble emulsions (HASE), NPJI and NPJ2, were experimentally investigated. At the same polymer concentration, NPJ1 is appreciably more viscous and elastic than NPJ2. The high hydrophobicity of NPJ1 allows hydrophobic associations and more junction sites to be created, leading to the formation of a network structure. Under shear deformation, NPJ1 exhibits shear-thinning behaviour as compared with Newtonian characteristics of NPJ2. NPJ1 and NPJ2 exhibit a very high and a low level of elasticity respectively over the frequency range tested. For NPJ1, a crossover frequency appears, which is shifted to lower frequencies and hence, longer relaxation times, as concentration increases. Three different surfactants anionic SDS, cationic CTAB, and non-ionic TX-100 were employed to examine the effects of surfactants on the rheology of HASE. Due to the different ionic behaviour of the surfactant, each type of surfactant imposed different electrostatic interactions on the two HASE polymers. In general, at low surfactant concentration, a gradual increase in viscosity is observed until a maximum is reached, beyond which a continuous reduction of viscosity ensues. Viscosity development is a combined result of HASE-surfactant interactions, accompanied by constant rearrangement of the hydrophobic associative junctions, and electrostatic interactions.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2010년도 춘계학술발표회 논문집
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• pp.193-193
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• 2010

이전의 연구에서 우리는 선응집 기술을 적용한 중질탄산칼슘의 크기에 따른 수초지의 물성을 평가하였다. 이때 선응집 기술이 적용된 충전물의 입도와 분포를 측정하기 위해 light diffraction spectroscopy (LDS) 가 사용되었다. 경질탄산칼슘과 양이온성 고분자의 흡착 현상을 알아보기 위한 이번 연구에도 LDS가 사용되었으며, 일회성으로 입자의 크기와 분포를 측정하는 것에서 더 나아가 시간의 흐름에 따라 응집체의 형성과 파괴, 재성장을 관찰할 수 있는 도구로서 역할 하였다. 본 연구에서 우리는 세 가지 경우로 나누어 경질탄산칼슘의 응집 현상을 관찰하였다. 첫째로 경질탄산칼슘에 흡착되는 양이온성 고분자의 특성, 분자량과 전하밀도, 을 달리하여 응집체의 성장과 파괴를 관찰하였다. 둘째, 양이온성 고분자로 중질탄산칼슘을 응집시켜, 경질탄산칼슘 응집체의 경우와 입도와 전단 안정성 등을 비교하였다. 마지막으로 나노 크기의 실리카 투입이, 마이크로 크기의 경질탄산칼슘 응집체가 강한 전단에 의해 파괴되었을 때, 응집체의 전단 안정성이나 재성장 측면에 도움을 주는지 관찰하였다. 내첨용 충전물로써 경질탄산칼슘의 사용이 전 세계적으로 늘고 있는 시점에서 양이온성 고분자 첨가에 의한 경질탄산칼슘의 응집 현상을 관찰하는 것은 일반적인 제지 공정에서 경질탄산칼슘의 거동을 이해하는데 도움이 될 뿐만 아니라, 내첨용 충전물 첨가에 따른 종이의 강도 저하 방지를 위한 선응집 기술의 적용에도 도움이 될 수 있을 것으로 생각한다.

• 펄프종이기술
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• 제41권4호
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• pp.65-72
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• 2009

We investigated the effect of polyelectrolyte types in Layer-by-Layer multilayering and furnish combination on physical properties of paper. Handsheets were made from pulp fibers with different polyelectrolytes composition, and their density, formation, tensile strength, strain, tear strength and burst strength were evaluated. The density of handsheet was slightly decreased by polyelectrolyte multilayering. Formation did not show a significant change, but all mechanical properties were increased by polyelectrolyte multilayering. Remarkable improvement in tensile and tear strengths was obtained when pulp fibers were treated with cationic starch and poly styrene 4-sulfonate. Irrespectively of final ionicity of pulp fiber, tensile index, strain and tear strength of paper could be improved simultaneously by polyelectrolyte multilayering.

• 한국의류학회지
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• 제24권3호
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• pp.385-392
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• 2000

The adsorption ability of dyes on chitin, a natural polymer was investigated for decolorization of dye wastewater. Chitin was manufactured in lab by decalcification in dilute aqueous HCI solution and deproteination in dilute aqueous NaOH solution with shrimp shells. Absorbance of residue solution of dyebaths after dye adsorptions of chitin were measured in varieties of dye concentration and dipping periods. Four kinds of dyestuffs were used, C.I.Acid Blue 29. C.I.Direct Blue 6, C.I.Reactive Orange 12 and C.I.Basic Red 18. When chtin 1g was dipped in 0.05% of dyebath with stirring, maximum adsorption ratio of each kind of dyes was exhibited as 91.6% for C.I.Acid Blue 29, 95% for C.I.Direct Blue 6, 58.2% for C.I.Reactive Orange 13 and 75.8% for C.I.Basic Red 19. It shows that chitin has better adsorption abilities of ionic dyes of acid, direct and basic dye than non-ionic reactive dye. And chitin has better adsorption abilities of anionic acid direct dyes than cationic basic dye because of the presence of nitrogen atoms. All kinds of dyestuffs used showed speedy absorption effects by chitin, so chitin can absorb much amount of dyes in 5 mimutes reach to equilibrium of adsorption in 2 hours after dipping. Basic dye was absorbed the most speedily in 5 minutes, although maximum adsorption ratio is not high. That reason can be thought that chitin surface is essentially negatively charged due to polar funtional groups.

• 대한의용생체공학회:의공학회지
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• 제15권3호
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• pp.259-264
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• 1994

혈액으로부터 헤파린을 선택적으로 제거하기 위하여 cellulose 기질에 양이온 고분자인 poly(allylamine)(PALA)을 새로운 방법으로 고정화하여 헤파린 제거제를 제조한 다음 in vitro 헤파린 용액내에서 흡착실험을 행하여, 미처리 cellulose control과의 흡착능을 비교하였다. 제조된 헤파린 제거제와 미처리 cellulose의 표면적은 각각 1.36 및 $2.56m^2$/g로 개질처리된 경우의 표면적이 약 1/2로 감소하였다. 또한 제조된 헤파린 제거제에 흡착된 헤파린의 양은 개질 방법에 따라 0.16~$0.03{\mu} g$/$cm^2$로 미처리 celluose($0.03{\mu} g$/$cm^2$)보다 월등히 우수한 헤파린 흡착능을 나타내었다.

• Bulletin of the Korean Chemical Society
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• 제26권4호
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• pp.548-552
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• 2005

The interaction between ionic surfactants and different nonionic molecules and polymers are studied using ion surfactant selective electrode. From the experimental data, critical concentrations of the interaction and binding process are evaluated. The interaction between hexadecyltrimethylammonium bromide (HTAB) with polyethylene glycol (PEG) in three molecular weights (1000, 10000 and 100000) and also schiff-bases, 2-[2-carboxyphenyl nitrilomethylidyne]-phenol (ortho CNP), 2-[3-carboxyphenyl nitrilomethylidyne]-phenol (meta CNP)and 2-[4-carboxyphenyl nitrilomethylidyne]-phenol (para CNP) with the potentiometric method were investigated using HTAB membrane selective electrode. In the case of PEG with increasing molecular weights more interaction to HTAB occurs. The electromotive force (EMF) data also showed that interaction between para CNP with HTAB is more than the other schiff-bases. It seems this case related to less space interference of COOH group for that compound. The onset of binding ($T_1$) of course is the same for three schiffbase molecules.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권6호
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• pp.516-521
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• 2005

Drug delivery to the lymphatic system may be important in terms of the treatment with lymphatic involvement, such as tumor metastases and immunization. Especially, drug transport via the intestinal lymphatics after oral administration has been attracted lots of interests. The purpose of this study was to prepare cyclosporin A (CSA)-loaded liposomes, with different characteristics, and evaluate their mucoadhesivity. Three liposome preparations were formulated: cationic stearylamine liposomes (SA-Lip), anionic phosphatidylserine liposomes (PS-Lip), Polymer (chitosan)-coated liposomes (CS-Lip), and characterized. The liposome preparations were found to be spherical in shape, with PS-Lip being the smallest. The liposome preparations exhibited entrapment efficiencies in the order: PS-Lip $(52.5{\pm}2.9%)$ > SA-Lip $(48.8{\pm}3.3%)$ > CS-Lip $(41.7{\pm}4.2%)$. Finally, mucoadhesive tests were carried out using rat intestine, with SA-Lip (67%) showing the best adhesive rate of the three preparations (PS-Lip: 56%, CS-Lip: 61%). These results suggest that a positive charge on the surface of drug carriers may be an important factor for the intestinal drug delivery.

• Asian Pacific Journal of Cancer Prevention
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• 제17권7호
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• pp.3061-3063
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• 2016

Exploiting the immune system to abolish cancer growth via vaccination is a promising strategy but that is limited by many clinical issues. For DNA vaccines, viral vectors as a delivery system mediate a strong immune response due to their protein structure, which could afflect the cellular uptake of the genetic vector or even induce cytotoxic immune responses against transfected cells. Recently, synthetic DNA delivery systems have been developed and recommended as much easier and simple approaches for DNA delivery compared with viral vectors. These are based on the attraction of the positively charged cationic transfection reagents to negatively charged DNA molecules, which augments the cellular DNA uptake. In fact, there are three major cellular barriers which hinder successful DNA delivery systems: low uptake across the plasma membrane; inadequate release of DNA molecules with limited stability; and lack of nuclear targeting. Recently, a polysaccharide polymer produced by microalgae has been synthesized in a form of polymeric fiber material poly-N-acetyl glucosamine (p-GlcNAc). Due its unique properties, the F2 gel matrix was suggested as an effective delivery system for immune and gene vaccinations.

• 한국응용과학기술학회지
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• 제30권1호
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• pp.96-115
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• 2013

본 연구는 항균성 코팅제의 개념과 동향파악으로 항균성 코팅제의 연구개발의 방향을 설정하는데 도움을 주기 위한 것이다. 항균제는 미생물을 제거하거나 성장을 저지하는데 사용되는 화합물이며 항균 코팅제에 함유되는 항균제용 재료는 무기물, 금속, 저분자 유기물, 천연유기물, 고분자가 있다. 항균코팅제는 생활용품, 병원용품, 산업용품, 전자제품, 의류, 건축 내장재 등의 표면의 항균성 부여에 쓰인다. 기존 항생제는 세균의 세포벽을 손상하지 않고 미생물을 침투하나 항균성 고분자는 세포막을 파괴하므로 항생제의 내성을 방지할 수 있다. 대부분의 고분자 항균제는 양이온 고분자에 초점을 맞추고 있다. 항균제의 분자설계와 코팅제 배합의 합리화로 항균제의 선택성, 내구성, 독성 문제가 개선될 것이다.

• Corrosion Science and Technology
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• 제16권4호
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• pp.187-193
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• 2017

Polymer amines are found to show distinct corrosion inhibition effects in acidic media. The functional groups of organic compounds have a wide role in the physical and chemical properties, for the inhibition efficiency with respect to steric factors, aromaticity, and electron density. The influence of $H^+$ ions and $Cl^-$ ions on the corrosion inhibitive effect of poly(p-aminophenol) for iron in hydrochloric acid was studied using electrochemical methods such as impedance, linear polarization, and Tafel polarization techniques. The experiments were conducted with and without the inhibitor, poly(p-aminophenol). The concentration range of $H^+$ ions and $Cl^-$ ions are from 1 M to 0.05 M and 1 M to 0.1 M, respectively. With the inhibitor poly(p-aminophenol), this study shows that inhibition efficiency decreases with the reduction of $H^+$ ion and $Cl^-$ ion concentrations in aqueous solution. Further, it reveals that the adsorption of an inhibitor on the surface of iron is dependent on the concentrations of $H^+$ and $Cl^-$ ions in the solution and the adsorption of inhibitor on the iron surface through the cationic form of amine.