• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.183-183
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• 2006

Hyaluronic acid and chitosan-based poly(ethylene oxide) (HA-PEO and Chitosan-PEO) hydrogels have been employed as unique biomedical polymeric materials with properties such as bioactivity from polysaccharide, biocompatibility of HA and chitosan as well as PEO and control release of bioactive molecules from the hydrogel itself. We here examine in situ hydrogels based on hyaluronic acid and chitosan in terms of their synthesis, mechanical properties, morphologies and in vitro cellular interactions on their surface and inside. In vivo bone regeneration of HA-PEO and Chitosan-PEO hydrogels was compared with in mouse model.

• Proceedings of the Korean Fiber Society Conference
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• 1998.04a
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• pp.148-151
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• 1998

대부분의 고분자 가공공정에 있어서 가공원액(고분자 액체 또는 용융물)은 선형영역을 벗어나는 큰 크기의 변형을 받으므로 기존의 선형 점탄성 이론으로는 그 공정해석이 불가능하다. 그러므로 대변형하에서 고분자 물질의 비선형 거동 해석은 실제 공정과 관련된 공학적인 관점에서 볼 때 매우 중요한 과제라고 할 수 있다. 특히 응력완화 실험은 점탄성 액체의 비선형 완화 거동을 고찰하고 지금까지 제시된 각종 구성방정식을 평가하는데 유용하다.(중략)

• Proceedings of the Korean Fiber Society Conference
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• 1998.04a
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• pp.144-147
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• 1998

다양한 변형 양식에 대한 고분자 물질의 응답특성을 예측하기 위해서는 완화 스펙트럼 H(λ) 또는 선형 완화 탄성율 G(t)를 결정하여야 한다. 완화 스펙트럼은 연속 완화 스펙트럼과 불연속 완화 스펙트럼(혹은 이산 완화 스펙트럼)으로 구분되며, 완화 스펙트럼과 완화 탄성율을 동적 점탄성으로부터 계산할 수 있는 여러 가지 방법들이 많은 연구자들에 의해 수행되어 왔다.(중략)

• Archives of Pharmacal Research
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• v.15 no.1
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• pp.91-94
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• 1992

A convenient method for the preparation of N-aryl thiazolines 4a b, 2, 2-dichlorothiophene 5, thiazolinones 6 and 8 and 2, 6-dihydrothiopyran 2-thione 9 derivatives is described. This depends on interaction of 3, 3-dimercapto-1(4-biphenyl)-2-propen-1-one 1 with dichloroethane, amines, trichloroacetylchloride, chloroacetamide, ethylene oxide and epichlorohydrin. Antimicrobial activity of the obtained products was studied.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2008.10a
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• pp.11-12
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• 2008

Poly(ethylene oxide)(PEO) of molecular weight of 300,000 was crosslinked by UV irradiation in the presence of crosslinker. The photochemical crosslinking of PEO was enhanced by the addition of dimethacrylate crosslinkers in the film. Percent conversion of the polymer into gel as well as water absorbency were investigated gravimetrically. Gel fraction of PEO films increased with increasing crosslinker concentration. In the case of photocrosslinked PEO films with benzophenone, gel fraction reached about 95%. The thermal behavior of crosslinked PEO films was characterized by thermogravimetric analysis. The maximum decomposition temperature increased with increasing crosslinker concentration.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.175-178
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• 2001

일반적으로 점탄성 거동을 나타내는 고분자 액체의 전단유동특성(shear flow properties)을 평가하기 위하여 정상전단(steady shear), 동적전단(dynamic shear), 응력완화(stress relaxation) 그리고 크리프(creep) 및 크리프 회복(creep recovery) 실험 등이 활용되고 있다[1], 이때 영전단점도(zero shear viscosity)와 정상상태 회복 컴플라이언스(steady-state recoverable compliance)는 정상상태(steady state)에서 얻어지는 물리량으로, 각 실험방법으로부터 직접적 또는 간접적으로 측정이 가능하다. (중략)

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1405-1407
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• 2009

We prepared polystyrene-b-poly(2-vinyl pyridine) (PSb-P2VP) lamellar films which is hydrophobic block-hydrophilic polyelectrolyte block polymer have 57 kg/mol-b-57 kg/mol. The result of UV-visible absorption spectra supported that effect of poly(ethylene oxide) on the band gap tuning of PS-P2VP photonic gel like salt effect.

• Journal of Periodontal and Implant Science
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• v.41 no.6
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• pp.263-272
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• 2011

A number of surface modification techniques using immobilization of biofunctional molecules of Titanium (Ti) for dental implants as well as surface properties of Ti and Ti alloys have been developed. The method using passive surface oxide film on titanium takes advantage of the fact that the surface film on Ti consists mainly of amorphous or low-crystalline and nonstoichiometric $TiO_2$. In another method, the reconstruction of passive films, calcium phosphate naturally forms on Ti and its alloys, which is characteristic of Ti. A third method uses the surface active hydroxyl group. The oxide surface immediately reacts with water molecules and hydroxyl groups are formed. The hydroxyl groups dissociate in aqueous solutions and show acidic and basic properties. Several additional methods are also possible, including surface modification techniques, immobilization of poly(ethylene glycol), and immobilization of biomolecules such as bone morphogenetic protein, peptide, collagen, hydrogel, and gelatin.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.196-196
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• 1994

DDS에 활용될 수 있는 고분자 소재를 개발할 목적으로 물성 및 응용성이 우수한 고분자 겔에 관한 연구를 수행하였다. Ethylene oxide,propylene oxide 각각의 copolymer인 poloxamer등의 prepolymer들을 triisocyanate로 가교시키고 diisocyanate 로 chain이 연장된 "soft hydrogel"을 제조하였다. 모델 약물을 선정하여 crosslinker와 extender의 조절에 따른 hydrogel의 약물 방출 조절능을 조사하였으며 그 기전을 규명하고자 하였다. 가교부위에 urethane bond를 함유한 soft hydtogel은 건조상태에서도 고무와 같은 전연성을 보여 일반적인 hydrogel과 대비되는 특성을 보였으며 이에 따른 다양한 활용성이 기대되었다. Extender및 crosslinker의 비율에 따라서 이 rubber elasticity가 조절되었다. 가교도가 감소할수록 팽윤도가 상승하였고 이에 따른 약물방출도 증가함을 확인하였다. 또한 Prepolymer의 분자량 및 친수/소수성등의 물성에 따라 약물방출을 조절할 수 있었다. 제조된 hydrogel에 조절방출시 필요한 기능을 부가시키고자 poly(carylic acid)류와 IPN 공중합체를 합성하여 물성을 조사하였고 비이온성/양이온성/음이온성 모델약물을 선정하여 pH에 따른 가변적 팽윤도와 이온성 상호작용등에 근거한 약물 조절방출기전을 조사하였다.기전을 조사하였다.

• Journal of the Korean Ceramic Society
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• v.28 no.9
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• pp.739-749
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• 1991

Calcium hydroxide fine powders were synthesized by hydration of calcium oxide, and the shapes of powders obtained were examined for each synthethic condition. When distilled water was used as a solvent, irregular and agglomerated submicron powders were obtained, and it was impossible to control of the shapes. In methanol-added solutions, hexagonal plate-like particles were obtained, but addition of ethanol had no effect. However on the occasion that substituted ethylene glycol for ethanol of 5 vol%, hexagonal plate-like powders were obtained. The shapes of powders synthesized in acetic acid and salicylic acid solutions were hexagonal platelike, and were spherical and very fine in citric acid and oxalic acid solutions, respectively. But in some solutions, calcium salts were precipitated by the reaction between calcium and acid added. And the size of powders were very fine using ultrasonic vibration instead of mechanical agitation.