• Korean Chemical Engineering Research
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• v.54 no.3
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• pp.387-393
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• 2016

Fluorinated polyurethane coating solutions were synthesized from perfluoroalkyl alcohol, toluene diisocyanate, and polycarbonate diol as starting materials. Next, coating films were prepared by spin-coating the fluorinated polyurethane coating solutions on the PC substrates, followed by thermal curing at $120^{\circ}C$. The obtained fluorinated polyurethane coating films were characterized by FT-IR spectroscopy, UV-Vis spectrometer, contact angle tester and pencil hardness tester. Contact angle measurements of water on the coating films showed that the addition of perfluoroalkyl alcohol improved the water repellency and increased the contact angle from $81^{\circ}C$ to $111^{\circ}C$. However, the pencil hardness of coating films exhibited a constant grade of H, irrespective of the addition of perfluoroalkyl alcohol.

• Journal of Sensor Science and Technology
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• v.7 no.2
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• pp.97-102
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• 1998

Organic thin film EL devices using PPV(poly (p-phenylenevinylene)) as emitter were fabricated on various conditions and structures, their electro-optical properties were estimated. Fabricated EL devices had structures of single layer(ITO(indium tin oxide)/PPV/Mg), double layer(ITO/PVK(poly(N-vinylcarbazole))/PPV/Mg and ITO/PPV/Polymer matrix + PBD/Mg) and three layer (ITO/PVK/PPV/PS(polystyrene)+PBD(butyl-2-(4-bipheny])-5-(4-tert-butylphenyl-1,3,4-oxadiazole))/Mg), their electro-optical characteristics were compared with each other. In structure of double layer (ITO/PPV /Polymer matrix + PBD/Mg), the used polymer-matrices were PMMA(poly(methyl methacrylate), PC(polycarbonate), PS and MCH(side chain liquid crystalline homopolymer). When PS as a hole transport layer was used, the luminance characteristics on concentration of PBD was obtained. In results, current-voltage-luminance curves of fabricated devices had characteristics of tunneling effect and the device showed a stable light emitting.

• Journal of the Korean Society for Railway
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• v.19 no.1
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• pp.1-10
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• 2016

To improve the sound insulation performance of laminated glass in high speed trains, it is beneficial to study the relationship between the characteristics of interlayer films and the acoustical performance. In addition to those of conventional PVB (polyvinyl butyral), the dynamic mechanical properties of PVB derivatives and PC (polycarbonate), which are candidates for interlayer films, were analyzed. We assumed that PVB-HEMU, which has a glass transition temperature ($T_g$) around room temperature and a large tan ${\delta}$ (loss tangent) value, can be made to damp efficiently. The damping capability was tested utilizing sound transmission loss measurement and simulation under the identical structure of laminated glass in high speed trains. We also built a database for analysis of relations between interlayer film characteristics and acoustical performance; this was followed by the determination of sound transmission loss using the intensity technique and FEA.

• Elastomers and Composites
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• v.38 no.4
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• pp.295-302
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• 2003

The amount of shrinkage of injection molded parts is different from operational conditions of injection molding such as injection temperature, injection pressure and mold temperature, and mold design such as gate size. It also varies depending on the presence of crystalline structure in resins. In this study, part shrinkage was investigated for various operational conditions and resins. Poly(butylene terephthalate) (PBT) for crystalline polymer, and polycarbonate (PC) and poly(methyl methacrylate) (PMMA) for amorphous polymers were used. Crystall me polymer showed higher part shrinkage by about three times than that of amorphous polymers. Part shrinkage increased as melt and molt temperatures increased, and injection pressure decreased. Part shrinkage decreased as gate size increased since the pressure delivery is mush easier for larger gate sizes. Part shrinkage at the position close to the gate was larger than that or the position far from gate. This phenomenon might be occur by difference of residual stress.

• Journal of Adhesion and Interface
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• v.3 no.4
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• pp.10-18
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• 2002

Modern plastics are of great importance in many practical applications and their performance can be enhanced by surface modification to improve their hardness, wear and chemical resistance. The object of this study is invention of functional hardening coating materials which are applied to plastic, such as polycarbonate, polymethylmethacylate and acrylonitrilebutadienestyrene. In order to invention of hardening coating materials, we synthesized new silicone acrylate oligomer and prepared coating films containing silicone acrylate oligomer (SAOE) on PC substrate. The curing of coatings is performed by UV-radiation. As results of experiments, The properties of coating films which are contained SAOE is greatly improved in comparison with coating films non-contained SAOE. Especially, when 1 wt% SAOE was introduced into the coating formulation, the UV hardening coatings obtained showed the best surface hardness and gloss.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1512-1518
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• 2013

Polycarbonates (PCs) with six different end capping agents were synthesized from melt polymerization. Chemical structure of the synthesized PC was determined by FT-IR spectroscopy. The average molecular weight and distribution, glass transition and thermal degradation temperatures were determined by GPC, DSC and TGA. Average molecular weight changed with the chemical structure of end capping agent, and 4-tert-butylphenol was estimated as the optimum end capping agent. The average molecular weights of PCs decreased with the concentration of the agent, the number average molecular weight was observed as 20,000 - 30,000 when 0.05-0.15 mol% of 4-tert-butylphenol added in PCs. The melt viscosities and glass transition temperature of the PCs decreased with molecular weight. The change for adding method of the agent affected on both the molecular weight distribution and decrease in power law index.

• Applied Chemistry for Engineering
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• v.19 no.3
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• pp.287-294
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• 2008

Molecularly imprinted polymer (MIPs) membranes were prepared by UV polymerization to separate racemates with opposite physiological activity, and then its separation selectivity of racemates was carried out. Likewise, their properties were examined. Polycarbonate (PC) membrane was polymerized as small spot form in pore inner wall, but anodisc (AD) membrane was polymerized as film form with thickness 500~700 nm onto the membrane surface. Also the study on the separation selectivity of prepared MIPs membranes was carried out in L-Tryptophane (Trp) racemate solution. The results showed that AD MIPs membrane polymerized as a film form, which was achieved by solution polymerizaion consisting of over 90% cross-linking agent (ethylene glycol dimethacrylate; EGDMA) and under 30% dispersing agent (methanol; MeOH), had predominant 3.5 selectivity.

• Polymer(Korea)
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• v.25 no.4
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• pp.512-520
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• 2001

One of the most important factors which affect the mechanical properties of fiber-reinforced composite materials is the interfacial shear strength (IFSS). The IFSS of glass fiber and polycarbonate (PC)/styrene-co-acrylonitrile (SAN) blend system has been measured by the single fiber fragmentation test (SFFT). SAN contents were varied up to 30 wt% and the IFSS increased with the SAN contents. Styrene-co-maleic anhydride (SMA) was used as the compatibilizer and the glass fiber was surface treated with organosilane coupling agents. Addition of small amount of SMA in PC/SAN blend improved the IFSS by chemical bonding between maleic anhydride and silanol. The optimum MA content was 0.4 wt% of total matrix contents. Also, IFSS was greatly affected by the miscibility condition of SAN/SMA blends, which depended on the copolymer composition of SAN and SMA. It was found out that, higher IFSS could be obtained when the SAN/SMA blend was in miscible pairs. In case of SAN/SMA miscible pairs, the IFSS depended on the MA content in total matrix, not on the MA content in SMA.

• Textile Coloration and Finishing
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• v.34 no.2
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• pp.117-126
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• 2022

In this study, thermoplastic composites were manufactured using ABS(acrylonitrile butadiene styrene), PC(polycarbonate), and POE(polyolefin elastomer), which are thermoplastic plastics. Twin screw extruder and injection molding were used to manufacture thermoplastic composites. When the ABS/PC/POE thermoplastic composite material was manufactured, the POE mass fraction was set to 1 to 5 wt.%, and the thermal and mechanical properties according to the POE mass fraction were analyzed. Based on the physical properties of ABS/PC/POE, a 3D model in the form of an e-bike frame was created. After setting the boundary conditions, when an external load is applied, geometry simulation was performed to predict product performance. The ABS/PC/POE thermoplastic composite material exhibited the best physical properties when the mass fraction of POE was 3 wt.%. In the simulation results for the physical properties of the 3D model in the form of an e-bike frame, the best physical properties were shown when the mass fraction of POE was 2 ~ 3 wt.%. As a result, the manufacturing conditions for ABS/PC/POE thermoplastic composite materials were set, and research was conducted to reduce product development costs and development time.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.1864-1869
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• 2007

In this study, we compare thermal performance between four different types of cold plates for humanoid robot cooling. Two commercially available cold plates made of copper have different dimensions and internal flow paths: One has $20{\times}20$ $mm^2$ base area with micro-channels and the other has $62.5{\times}62.5$ $mm^2$ base area with 85 round pin-fins. And two different types of cold plates of $20{\times}20$ $mm^2$ base area with 7 mm high are made of PC (polycarbonate), which aims to reduce the weight of cooling system. All cold plates are mounted on a $20{\times}20$ $mm^2$ copper block with two cartridge heaters of 30 $W/cm^2$. The overall heat transfer coefficient and thermal resistances for the liquid-cooled cold plates are obtained. The copper cold plate with micro-channels showed the best performance. Polycarbonate cold plates display fairly good thermal performance with more reduced system weight.