• Clean Technology
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• v.12 no.1
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• pp.19-25
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• 2006

In this study, photo-cuarable urethane methacrylate oligomers were synthesized from polyether type polyol (PP series, GP series), isocyanate (2,4-toluene diisocyanate) and hydroxy acrylate (hydroxypropyl methacrylate). We measured basic property including color, viscosity and refractive index of resulting urethane methacrylate. Also we measured tensile strength, elongation, and Young's modulus after photo curing. Photo curing speed was investigated using photo-DSC (TA instrument). In the case of similar polyol structure, as the molecular weight of polyol is increased, tensile strength, Young's modulus, curing rate were decreased, but elongation was increased. As the number of functionality of urethane methacrylate oligomer is increased, tensile strength, Young's modulus, curing rate were increased, but elongation was decreased.

• Macromolecular Research
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• v.15 no.6
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• pp.560-564
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• 2007

The photostabilization and cure kinetics of UV-curable, optical resins containing various formulations of photostabilizers were investigated to determine the system with the highest cure conversion and durability. Photo-DSC analysis revealed that increasing the concentration of a UV absorber (UVA) decreased both the crosslink density and the cure rate due to competition for the incident photons between the photoinitiator and the UVA, whereas including a hindered amine light stabilizer (HALS) hardly affected either the cure conversion or the cure rate due to its very low absorption of 365 nm. This result was confirmed by FTIR-ATR spectroscopy and UV-visible spectroscopy analyses. QUV ageing experiments showed that the cure conversion and durability were the highest for the UVA/HALS formulation at a ratio of 1 : 2, which is due to their synergistic action.

• Journal of Adhesion and Interface
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• v.15 no.1
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• pp.22-30
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• 2014

Self-photoinitiating acrylate (SPIA) which can undergo self-initiation under UV irradiation was synthesized by a Michael addition in the presence of a base catalyst. The SPIA polymerizations were investigated by photo-differential scanning calorimeter (photo-DSC) and surface physical properties such as pendulum hardness and pencil hardness. The results showed that the SPIA can cure upon UV irradiation by itself without a photoinitiator. But we found out that both the curing rate and the conversion were too low for the self-curing reaction of SPIA. In order to improve the SPIA curing properties, we introduced the SPIA/cationic hybrid system and observed the effects of the addition of commercial free radical type monomer and photoinitiator on the curing behaviors. SPIA/cationic hybrid system was the best suitable to improve the SPIA curing properties. The kinetic analysis indicated that the cationic monomer and photoinitiator apparently accelerated the cure reaction and rate of the hybrid SPIA system, mostly due to the synergistic effect of cationic monomer and photoinitiator increasing the mobility of active species and the generation of reactive species (free radical, cation) during the photopolymerization process. The physical properties showed that, unlike typical free radical system, the hybrid systems did not show oxygen inhibition effect because of cationic reaction on the coating surface.

• Applied Chemistry for Engineering
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• v.5 no.5
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• pp.857-861
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• 1994

UV curable hybrid systems have been investigated in the urethane acrylate based formulations where potentially irritant acrylate monomers have been substituted by vinyl ethers. Generally, among the systems studied, coating properties of hybrid system are superior to those of free radical hut inferior to those of cationic systems. When the content of acrylic oligomer is above 70%, however, hybrid system could render an excellent combination of coating and curing properties which outperforms both cationic and free radical systems. Photo-DSC has been used to follow the progress of crosslinking of various coating systems. Results imply that the critical factors in determining the curing rates of coating formulations are different depending upon the formulation characteristics. In the same type of hybrid formulations, the monomer/oligomer ratio rather than photoinitiator efficiency is the critical factor determining the curing rate of the systems.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1338_1339
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• 2009

Dye-sensitized solar cell (DSC) consists of photo electrode, counter electrode and electrolyte. Photo electrode has titanium oxide layer with dye molecule to create electrons. And counter electrode is made of one layer that has catalytic ability for redox system such as the iodide/triiodide couple. Most DSC researchers use platinum as catalyst on counter electrode because platinum has good catalytic ability and conductivity. Platinum is doped on fluorine-doped tin oxide glass with different methods such as sputtering method, electrochemical method and so on. In this paper, we deposit platinum on counter electrode glass with two methods. One is the radio frequency (RF) sputtering method and the other is the chemical method with heating treatment. Finally, we compare the photovoltaic characteristics of DSCs that are assembled using two different counter electrodes.

• Journal of Adhesion and Interface
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• v.14 no.4
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• pp.167-174
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• 2013

In this study, Ultraviolet (UV) curable urethane acrylates for ink binder was prepared by reaction of IPDI, polyether polyol and HEA. The UV curing behavior of compositions with HEA/PETA ratio on UV irradiation time was investigated by FT-IR spectrophotometer, probe tack tester and Photo-DSC. Conversion % and gel content were increased with increasing UV irradiation time, but probe tack was decreased. Storage modulus, tensile strength and decomposition temperature were increased as PETA content increased. In case of HEA/PETA ratio was 30/70, adhesion property of UV-cured composition on PMMA sheet was excellent.

• Journal of Adhesion and Interface
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• v.11 no.2
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• pp.41-49
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• 2010

Furan-containing epoxide monomers (8, 9) were designed and synthesized as carbon-neutral, environment-friendly adhesion material. Bicyclic skeleton were constructed using the Diels-Alder reaction of furan and methyl acrylate, both readily accessible starting material from a biomass via bio-refinery process. After reduction of ester functionality, resulting hydroxyl moieties were coupled to epichlorohydrin to provide the epoxy-functionalized furanic monomers (8, 9). The structure of new furanic monomers was confirmed by $^1H$ and $^{13}C$ NMR spectroscopy. As UV-curable monomers, basic properties such as UV curing time and the extent of UV curing were evaluated by photo DSC. Photo-curing shrinkages were measured by linear variable differential transformer transducer (LVDT) and the effect of molecular structure on shrinkage was considered. In addition, new synthetic compounds showed the shear strength over 3 MPa when they were photo-cured between polycarbonate plates, which indicates these compounds are feasible to use as photo-curable adhesive materials.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.2
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• pp.126-130
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• 2011

Transparent conductive oxide (TCO) is an important part in the construction of dye-sensitized solar cells (DSCs) because of its low sheet resistance, sufficient light transparent ability and high photoelectrical response as a porous photo-electrode material of DSCs. However, the use of TCO for the two DSC electrodes can result in significant cost increase for the less effective DSCs compared to Si based solar cell. Therefore, the replacement of TCO is required for the commercial production of DSCs. In this study, TCO electrodes are replaced by stainless steel mesh. The 3.44[%] efficiency of the prepared TCO-less DSCs sample was obtained.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.854-857
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• 2006

The synthesis of ester type, banana-shaped, photo - crosslinkable mesogens is described. The reactive mesogens, derivatives of 1,3-phenylene bis{4-[4'- (alken-1-yloxy)-biphenyl-4-carboxylate]benzoate}s, were synthesized varying the length of alkyl end groups. The obtained monomers and polymers were characterized by FT/IR, NMR spectroscopy, DSC, polarized optical microscopy, and X-ray diffractometry.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.76-78
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• 2004

근래에 이르러 Digital Photo에 대한 사용자들의 수요가 늘어나면서 DSC이나 Camera Phone으로부터 Photo용 Printer로의 Printing Solution 개발에 대한 요구가 증가하고 있다. 2003년에 미국과 일본의 회사들이 이런 용도로 PictBridge를 개발하였다. 이것은 Image File의 전송에 대한 것인데, 최근에 이르러 양질의 프린팅 서비스 제공을 위하여 XHTML을 전송하는 방식에 대한 연구가 진행 중이다. 본 논문은 Pictsridge 상에 HXHTML script을 전송하는 방식에 대한 내용을 담고 있다.