• 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.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.80-83
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• 2009

Application of UV curing technique for poly vinyl chloride (PVC) floor tiles coating has improved the quality of PVC floor. Various formulations including acrylated oligomers based on a polyurethane were blended with reactive monomers, photoinitiators and other additives. The used oligomers are commercial aliphatic urethane acrylates. Thin films were prepared on PVC tiles by bar coating with different formulations using UV radiation. The coating resins were characterized by FTIR. The properties of UV-cured films such as gloss grade and adhesion were examined. The properties of UV-cured films dependent on the influence of composition and processing conditions was studied. The investigation was conducted to achieve an optimal domain of composition and desired coating effect.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1254-1258
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• 2007

Electro-active polymer (EAP), one of the smart materials, is a new alternative offering ultra-precise movements and bio-compatibility. We present the results of the design, fabrication, and performance evaluation of a fabricated diaphragm-type polymer actuator using segmented polyurethane(SPU). This paper illustrates the relationship between the elastic modulus and maximum deflection as a key property of the Maxwell stress effect and also presents the relationship between the dielectric constant and maximum deflection as a key property of the electrostriction effect, especially in polymer actuators using SPU. A diaphragm-type actuator was used to induce an equation of the vertically distributed load by using a fully clamped circular plate as the boundary condition. To verify the equation, the results were compared to the data measured from load cell. In the near future, a low-cost check valves and bio-robot can be applied by its actuators.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.141-145
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• 2008

Because of world financial crisis, The Korea domestic construction industry has been damaged hugely on material supplying work. A current domestic material supply system can't react properly on a great rise of foreign exchange rate and raw material price, so the system has a problem which is not properly supplying material. To solve this problem, a more innovative material supply work system is seriously needed than ever. So this study wants to improve material supply system for supplying material right time, right place through applying a web-based system. Applying this, overall process of material-supply-work can be done on a web-based system for immediately understanding change of ordering and warehousing by material-supply-schedule to a domestic construction field.

• Textile Coloration and Finishing
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• v.22 no.3
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• pp.239-245
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• 2010

Breathable waterproof PET fabrics were prepared by the UV coating of UV-curable polyurethaneacrylate(PUA) formulation mixed with polyethyleneglycol(PEG) as a water soluble pore former. The dispersed PEG in the UV-cured coating was extracted by warm water, which can generate individual circular pores uniformly distributed all over the coating instead of pore channels. Accordingly the moisture permeability of the microporously coated fabrics increased substantially with increasing PEG addition without significant reduction of hydrostatic pressure. Also the silicone diacrylate addition in the formulation was beneficial in increasing the hydrostatic pressure. The UV-based microporous coating can be an alternative to conventional thermal curing of solventborne polyurethane coating owing to the enhanced environment friendliness and energy saving.

• Journal of the Semiconductor & Display Technology
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• v.16 no.1
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• pp.45-51
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• 2017

Poly(urethane acrylate) siloxane oligomers with Interpenetrating polymer netwoked nanoparticles were prepared to synthesize hard coating solution by reaction with diisocyanates. The diisocyanate combined siloxane hard coating solution showed more flexibility than the siloxane solution. In addition, diisocyanate resulted in improvement of curl property and surface hardness in the siloxane solution. Of the used diisocyanates, isophorone diisocyanate and acryloyloxy ethyl diisocyanate were good for UV hard coating solution. This effect will decrease brittleness in the siloxane solution using for plastic display plate.

• Transactions of The Korea Fluid Power Systems Society
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• v.2 no.2
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• pp.14-20
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• 2005

This study developed and evaluated a shoe cushioning system to reduce impact force patterns during running. The shoe cushioning system is composed with a poly urethane pocket, which contains water and porous grains to absorb the force against the weight inside the pocket. Load-displacement curves for the shoe cushioning system were obtained from an instrumented testing machine and the results were compared with various pockets that have air, water or grains. Mechanical testings showed that the pocket with 5 g particles was the best for the shoe cushioning system. This founding will be helpful to designing the shoe.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.6
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• pp.75-81
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• 2012

Dissimilar material friction welding such as STD11 and SCM440, we are considering of such things as strength and tenacity of welding interface, which consist of friction welding rotation frequency, friction heating pressure, upset forging-pressure, friction heating time, and upset forging-pressure time. From the study, obtaining the interrelationship between welding condition and quality(toughness, tenacity), we can set the best range of welding condition. while performing acoustic emission examination for the nondestructive evaluation, we can deduce the interrelationship among total acoustic emission counts, friction welding variable, and quality during friction welding, which can solve the manufacturing difficulty and enhance the economic value.

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.3
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• pp.259-265
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• 2006

We polymerized material of AA(Acrylic acid) and BMA(butyl methacrylate) to make up for the weak points of hydrogel contact lens. The synthesis process of silicone synthesis is as follows. Acrylate-PDMS(Polydimethylsiloxane)-Urethane prepolymer was composed after Diisocynate reacted with HEMA(2-hydroxyethylmethacrylate) under the catalyst and it reacted again with bis(hydroxyalkyl) terminated poly(dimethylsiloxane) with high oxygen transmissibility characteristics. HEMA(2-hydroxyethylmethacrylate) was used to make prepolymer that can be polymerized and the urethane was used to improve elasticity and oxygen transmissibility, copolymerization was performed with conventional hydrogel contact lens materials to make silicone hydrogel contact lens with higher oxygen transmissibility. For manufacturing of contact lens, We added BMA(Butyl methacrylate) with better elasticity and flexibility, and AA(Acrylic acid) with higher moisturizing to used contact lens materials. AIBN (Azobis2-methylpropionitrile) as initiator and EGDMA(Ethylene Glycol Dimethacrylat) as crosslinking agent were used and the lens with higher oxygen transmissibility and better moisturizing were manufactured complying with basic contact lens properties, which have several combination trial of each monomer characteristics. Compounding SN which included SILICONE, HEMA, NVP and EGDMA etc was showed by swelling ratio of 9.38% and water content of 23.7%. SN was showed by swelling ratio of 9.38%, water content of 23.7% and a visible ray transmissibility of 89%. SB which added BMA in the SN was showed by swelling ratio of 12.50%, water content of 18.56% and a visible ray transmissibility of 88%. SAB which added both AA and BMA in the SN was showed by swelling ratio of 8.33%, water content of 12.93% and a visible ray transmissibility of 88%.

• Korean Chemical Engineering Research
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• v.49 no.1
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• pp.75-82
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• 2011

Five different composition UV-cured poly(urethane acrylate-co-acrylic acid) (PU-co-AA) films have been prepared by reacting isophorone diisocyanate(IPDI), polycaprolactone triol(PCLT), 2-hydroxyethyl acrylate(HEA), and different weight ratio trimethylolpropane triacrylate(TMPTA) and acrylic acid(AA) as diluents, and characterized using a Fourier transform infrared spectroscopy(FT-IR). The adhesion properties onto the stainless steel, morphology, mechanical hardness, and electrical property of UV-cured PU-co-AA films were investigated as a function of acrylic acid(AA) content. All the PU-co-AA films are structure-less and the molecular ordering and packing density decreased with increasing content of AA due to the flexible structure and -COOH side chains in AA. The crosscut test showed that PU-co-AA films without AA and with low content of AA showed 0% adhesion(0B) and the adhesion of PU-co-AA films in the range of 40-50% AA increased dramatically as the content of AA increases. The pull-off measurements showed that the adhesion force of PU-co-AA films to stainless steel substrate varied from 6 to 31 kgf /$cm^2$ and increased linearly with increasing AA content. The mechanical hardness also decreased as the content of AA increases. This may come from relatively linear and flexible structure in AA and low crystallinity in PU-co-AA films with higher content of AA. The higher AA-containing PU-co-AA films showed higher dielectric constant due to the increase of polarization by introducing AA monomer. In conclusion, the physical properties of UV-cured PU-co-AA films are strongly dependent upon the content of AA and the incorporation of AA in polyurethane acrylate is very useful way to increase the adhesion strength of UV-curable polymers on the stainless steel substrate.