• Elastomers and Composites
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• v.49 no.1
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• pp.37-42
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• 2014

Terpolymer polymerized carbon monoxide, ethylene and propylene as monomer, Polyketone is low-cost material compared with general engineering plastics such as polyamide, polyester, polycarbonate. Moreover, it is excellent in mechanical properties, chemical resistance, fuel permeability and abrasion resistance. So, it is attracted attention as the environmental friendly material to replace conventional engineering plastics. In this study, has been prepared Polyketone/Rubber (Ethylene propylene copolymer, Acrylonitrile butadiene rubber, Ethylene acrylic rubber) blends to improve heat resistance and investigated characteristic behavior after heat/oil aging.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.159-165
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• 2004

The shrinkages of injection molded parts are different in molding operational conditions and mold design. It also differs from resins. The shrinkages of injection molded parts for PBT (polybutylene terephthalate), PC (polycarbonate),and glass reinforced PBT and PC have been studied for various operational conditions of injection molding. The part shrinkage of crystalline polymer, PBT was higher than that of amorphous polymer, PC by about two times. The part shrinkages of both polymers decreased as glass fiber content increases. Higher Injection temperature and lower injection pressure resulted in a higher shrinkage in both PBT and PC resins. As mold temperature increases the part shrinkage of PC decreased. However, the part shrinkage of PBT increased as mold temperature increases. The part shrinkage of both PBT and PC resins decreased as gate size increases since the pressure delivery is mush easier for a larger gate size. The part shrinkage of flow direction was less than that of the perpendicular direction to the flow for both pure and glass fiber reinforced resins. The part shrinkage at the position close to the gate was less than that of the position far from the gate.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.2 s.31
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• pp.11-16
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• 2004

Electronic devices are getting smaller due to integration of electronic chip, and heat generated in electronic devices can cause loss of performance and/or reliability of the devices. In this research, metals such as gold, nickel and copper are plated onto a porous membrane by electroless plating method to make an efficient micro-heatsinks. Electroless plating includes sensitization and activation steps in pre-treatment steps. A polycarbonate(PC) membrane was sensitizied, activated and deposited in each metal solution for plating. Among manufactured microfibrils, heat transfer and radiation properties of Ni-microfibril with high surface area were more effective than those of $Au^-$ and Cu-microfibril.

• Child Health Nursing Research
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• v.10 no.1
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• pp.108-116
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• 2004

Purpose: There has been a number of reports on elution of bisphenol-A, an endocrine disrupting chemical, from milk bottles, all concerning the potential health effect of the substance. In this study, we measured the elution of bisphenol-A from milk bottles during boiling-water sterilization, to suggest a safe sterilization method. Method: Through the survey of 200 mothers, 78.5％ of them expressed their concern on the possible harmful effect of bisphenol-A, which might be eluted from the bottles. And it was found that most mothers use boiling-water to sterilize bottles; duration of boiling bottles could be divided into three groups of 3, 5, and 10 minutes. We measured the elution of bisphenol- A from three different brands of bottles, subject to various mode of sterilization found in the survey. Result: In all the measurements, the concentration of the eluted bisphenol-A was in the range of 0.3 - 0.7 ppb, far below 2.5ppm, the level set up by Korea Food ％amp; Drug Administration(KFDA) for a potential harmful effect. Conclusion: Although trace amount of bisphenol -A can be eluted from polycarbonate milk bottles during sterilization, and bottle feeding, the amount is found to be too small to cause any health related impact for infants.

• Journal of Information Display
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• v.10 no.3
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• pp.131-136
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• 2009

This is a report on the fabrication of a flexible OTFT backplane for electrophoretic display (EPD) using a printing technology. A practical printing technology for a polycarbonate substrate was developed by combining the conventional screen and inkjet printing technologies with the wet etching and oxygen plasma processes. For the gate electrode, the screen printing technology with Ag ink was developed to define the minimum line width of ${\sim}5{\mu}m$ and the thickness of ${\sim}70nm$ with the resistivity of ${\sim}10^{-6}{\Omega}{\cdot}cm$, which are suitable for displays with SVGA resolution. For the source and drain (S/D) electrodes, PEDOT:PSS, whose conductivity was drastically enhanced to 450 S/cm by adding 10 wt% glycerol, was adopted. In addition, the modified PEDOT:PSS could be neatly confined in the specific S/D electrode area that had been pretreated with oxygen. The OTFTs that made use of the developed printing technology produced a mobility of ${\sim}0.13cm^2/Vs.ec$ and an on/off current ratio of ${\sim}10^6$, which are comparable to those using thermally evaporated Au for the S/D electrode.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1104-1108
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• 2004

A Study has been made of surface modification of various polymers by ion implantation to change the optical transmittance property at ultraviolet ray (UV, $200\sim400nm$). The substrates were PC (Polycarbonate), PET(Polyethyleneteraphtalate) and PP (Polypropylene). The effects of ion implantation on the change of optical transmittance were investigated in relation to ion species, implantation energies and ion fluences. The N, Ar, Kr, Xe ion implantation performed at ion energies from 20 to 50keV. The fluences ranged from $5\times10^{15}$ to $7\times10^{16}ions/cm^2$. UV/Vis transmittance spectroscopy, FT-IR and XPS were used to investigate optical transmittance, chemical structure and surface chemical state of irradiated polymer. Surface color was changed from the yellow to the dark brown and the transmittance of UV ray in the range UV-A($320\sim400nm$) decreased more than 80% after ion implantation.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.1
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• pp.81-85
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• 2011

Recently, the electronic parts are to be thinner plate, smaller size, light weight material and CPU, HDD and DRAM in all the parts have been produced on the basis of the high speed and greater capacity. Also, conventional goods have replaced a LED (Light-Emitting Diode) in lighting products so; such industry devices need to have cooling. To maximize all the performance on the heat-radiated products, the area of heat-radiated parts is required to be cooled for keeping the life time extension and performance of product up. Existing cooling systems are using radiant heat plate of aluminum, brass by extrusion molding, heat pipe or hydro-cooling system for cooling. There is a limitation for bringing the light weight of product, cost reduction, molding of the cooling system. So it is proposed that an alternative way was made for bringing to the cooling system. EP (Engineering Plastic) of low-cost ABS (Acrylonitrile butadiene styrene Resin) and PC (Polycarbonate) was coated with brass and the coating made the radiated heat go up. The performance of radiant heat plate is the similar to the existing part. We have studied experimentally on the radiated heat plate for the light-weight, molding improvement and low-cost. From now on, we are going to develop the way to replace the exiting plate with exterior surface of product as a cooling system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.23 no.11 s.170
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• pp.2050-2057
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• 1999

It is necessary to improve mechanical and optical properties in the optical disk substrates as the information storage devices with high storage density using short wavelength laser are being developed. Injection compression molding is regarded as the most suitable process to manufacture optical disk substrates with high dimensional accuracy, low residual stresses, and superb optical properties. In the present study, polycarbonate optical disk substrates were fabricated by injection compression molding and the birefringence, regarded as one of the most important optical properties for optical disk, is measured. The effects of various processing conditions upon the development of birefringence distribution were examined experimentally. It was found that the values of the birefringence distribution were very sensitive to the mold wall temperature history and the variance of the birefringence distribution in the radial direction was affected by the level of the packing and the compression pressure.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.11
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• pp.131-137
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• 2009

A pair of connectors for transferring torque is widely used in various types of a mechanical system. By the repetition of mechanical contact between a pair of connector, wear occurs easily. This kind of defect sometimes can cause a serious problem of health in case of the connector is used in a refrigerator. In this work, the material combination of connectors was experimentally studied to reduce the amount of wear; for the combination of connectors, various types of engineering materials including polyacetal, polycabonate, stainless steel (STS-304), NiP coated STS-304, and STS-310 were evaluated to check each wear behavior. Also an effective method of wear test was suggested for precise controlling of wear conditions such as contact area, contact force, and relative motion speed. From the test results, it was found out that a pair of polyacetal to STS-304 and STS-310 showed the lowest specific wear rates among other pairs.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.742-745
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• 2001

Plastics are one of difficult materials for recycling due to their characteristics in use. Recycling ratio of waste plastics was around 40% in last year in Japan, which includes energy recovery. Feed stock recycling and mechanical recycling are not easy because of additives in commercial plastics. Then, pyrolysis treatments have been done to recovery energy. Although plastics are easy to fire, complete combustion of them is not easy if anti-firing agents are added especially. Therefore, researches on pyrolysis or combustion behaviors of plastics containing additives are important from a view point recycling of plastics. Direct observation of popular plastics like polystyrene (PS), polycarbonate (PC), polyphenyle ether (PPE) and polyvinyl chloride (PVC) to investigate their pyrolysis behaviors in the present study. In case of PS, melting and gas evolution started at 9$0^{\circ}C$ and 39$0^{\circ}C$ respectively. And combustion finished at 445$^{\circ}C$. On the other hand, more than $600^{\circ}C$ and sufficient oxygen are required for complete combustion of PC and PPE.