• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.8
• /
• pp.846-851
• /
• 2004

Transparent conducting indium tin oxide (TC-ITO) thin films on polymeric substrates have been deposited by a dc reactive magnetron sputtering without heat treatments. The polymeric substrates are acryl (AC), poly carbornate (PC), and polyethlene terephthalate (PET) as well as soda lime glass is also used to compare with the polymeric substrates. Sputtering parameters are an important factor for high quality of TC-ITO thin films prepared on polymeric substrates. Furthermore, the material, electrical and optical properties of as-deposited ITO films are dominated by the ratio of oxygen partial pressure. As the experimental results, the surface roughness of ITO films becomes rough as the oxygen partial pressure increases. The electrical resistivity of as-deposited ITO films decreases initially, and then increases with the increase of oxygen partial pressure. The optical transmittance at visible wavelength for all polymeric substrates is above 82 %.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.07a
• /
• pp.447-450
• /
• 2002

Recently polymeric insulators and arresters are being used for outdoor high voltage applications. Polymeric insulators for transmission line have significant advantages over porcelain and glass insulators, especially for ultra-high voltage(UHV) transmission lines. Their advantages are light weight, vandalism resistance and hydrophobicity. Polymeric insulator kind are a relatively new technology, but their expected life is still unknown. In this paper, the material property for polymeric insulating material such as silicone rubber and EPBM is investigated by cross-link time and the relation between tracking resistance and W resistance is analyzed by IEC 60587 and W aging experiment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.20 no.3
• /
• pp.273-280
• /
• 2007

In this paper, the ZnO surge arrester performance of power distribution class has been studied under different manufacturing conditions such as housing materials(polymeric, porcelain), interface sealants and one-body molding type. In the recent years, the polymeric ZnO surge arresters have been developed and put into operations based on their excellent characteristics. For polymeric surge arresters, the inner gas volume is extremely small, especially in solid insulation polymeric arresters there are not any gas volume inside arresters in the structure due to polymeric materials are filled into the internal gas volume. The sealing integrity is related to safe operation of surge arrester, the prime failure reason of porcelain housed arresters is moisture ingress. In this paper, the sealing integrity of polymeric surge arresters is investigated with moisture multi-aging test and ingress test. The evaluation techniques are used to inspect the sealing integrity of polymeric arresters, including leakage current, surface temperature, reference voltage and dissipation factor.

• Structural Engineering and Mechanics
• /
• v.32 no.3
• /
• pp.429-445
• /
• 2009

Thermal stability of quasi-isotropic composite and polymeric structures is considered one of the most important criteria in predicting life span of building structures. The outdoor applications of these structures have raised some legitimate concerns about their durability including moisture resistance and thermal stability. Exposure of such quasi-isotropic composite/polymeric structures to various and severe climatic conditions such as heat flux and frigid climate would change the material behavior and thermal viability and may lead to the degradation of material properties and building durability. This paper presents an analytical model for the generalized problem. This model accommodates the non-linearity and the non-homogeneity of the internal heat generated within the structure and the changes, modification to the material constants, and the structural size. The paper also investigates the effect of the incorporation of the temperature and/or material constant sensitive internal heat generation with four encountered climatic conditions on thermal stability of infinite cylindrical quasi-isotropic composite/polymeric structures. This can eventually result in the failure of such structures. Detailed critical analyses for four case studies which consider the population of the internal heat generation, cylindrical size, material constants, and four different climatic conditions are carried out. For each case of the proposed boundary conditions, the critical thermal stability parameter is determined. The results of this paper indicate that the thermal stability parameter is critically dependent on the cylinder size, material constants/selection, the convective heat transfer coefficient, subjected heat flux and other constants accrued from the structure environment.

• Transactions on Electrical and Electronic Materials
• /
• v.7 no.5
• /
• pp.235-239
• /
• 2006

Charge dynamics in polymeric materials after aged under ac electric field using the pulsed electroacoustic (PEA) technique is reported. The emphasis is placed on charge decay. The charge dynamics of the ac aged additive free low density polyethylene (LDPE) samples under dc bias differ from the sample without ac ageing, indicating changes brought in by ac ageing. It is believed that a slow decay rate of charge in the ac aged sample is related to the formation of deep traps in the material. However, chemical analysis by infrared spectroscope (FTIR) and Raman microscope reveals no significant chemical changes taken place in the bulk of the material after ac ageing. Further experiments on irradiated LDPE have revealed a similar behaviour, i.e. the charge decay is slower in irradiated samples than that of fresh sample. The findings presented clearly indicate that space charge measurement can be used as a diagnostic tool to monitor ageing in polymeric materials.

• Tribology and Lubricants
• /
• v.12 no.3
• /
• pp.39-47
• /
• 1996

The magnetic fibrous polymeric oil filter elements for industrial lub-systems were obtained by pneumoextrusion processing prepared from thermoplastic pqlymer (polyamide) containing a magnetic particulate filler (Ba ferrite), and treated subsequently in a magnetic fields. Using the standard laboratory oil filtration test rig, metallic particle quantifier and image analyser system, the dependence of filtration charateristics of the magnetic filter media on the parameters of porosity and magnetic properties was investigated. The pressure drops and efficiencies of lubricating filter elements were measured on the packing density and magnetised filler content of filter element. Also, the industrial lub-systems such as lubricant filters for gear test rig and electric discharge processing machine were used for testing the flitrational characteristics of tl, c magnetised filter elements. The magnetic fibrous polymeric filter material was shown to possess a highly filtration efficiency in filtering the fine ferrous particles with increasing the magnetic force of filter element. Therefore, it is expected that the magnetic fibrous polymeric filter material should be used for effective oil filrers on the industrial lub-systems.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.07a
• /
• pp.427-430
• /
• 2002

This paper presents on contamination performance of polymeric outdoor insulator with different contaminant accumulation. The ESDD (equivalent salt deposit density), tracking resistance and clean-fog test were performed to investigate the characteristics of contamination performance on polymeric outdoor insulator. Furthermore, we evaluated together with the porcelain samples for its comparison. It is found that ESDD of polymeric and porcelain insulator depends on the installation position. This surface accumulation of contaminant lead to the loss of surface hydrophobicity, expecially upper shed part of polymeric insulator. In addition, the effect of an artificial contaminant on the tracking resistance by inclined-plane method and leakage suppression ability under clean fog was surveyed. The time of tracking failure did not appear to change significantly with a much contaminant accumulation, while leakage current under clean-fog increased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.06a
• /
• pp.513-514
• /
• 2006

This paper presents the temperature characteristics with the structure of 18 kV surge arresters for distribution system. Three types of polymer arrester were fabricated and a ceramic arrester was also prepared to investigate. Below $100^{\circ}C$, three types of polymeric arresters exhibited almost the same leakage current value, but above $100^{\circ}C$, the polymeric arresters whose module was injected into polymeric housing with the grease exhibited the highest leakage current. In contrary, the arresters being manufactured by directly injecting silicone rubber onto arrester module exhibited the lowest leakage current. The rapid rising of leakage current of the polymeric arresters with the grease at $120^{\circ}C$ was because of the deterioration of the insulation characteristics of the grease between the FRP module and the silicone housing. All polymeric arresters exhibited the same surface temperature characteristics but the ceramic arresters was slower than the polymer arrester in heat emission despite the lowest leakage current. It was thought that the air layer between ZnO varistor blocks and the ceramic housing prevented the heat emission.

• Membrane Journal
• /
• v.7 no.1
• /
• pp.15-21
• /
• 1997

Carbon molecular sieve (CMS) membranes were synthesized by the pyrolysis of polymeric precursors. The CMS materials had oxygen-nitrogen selectivities much higher than those observed for the polymeric precursors. Typically molecular sieving materials have diffusion selectivities much higher than polymeric materials. This has been identified as a result of higher entropic selectivity of the molecular sieving materials. A study of the development of molecular sieving properties as the polymeric precursor is pyrolyzed into a CMS material will offer us an insight into polymeric molecular structures needed for enhanced entropic selectivity membrane materials.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.07b
• /
• pp.849-852
• /
• 2004

Indium tin oxide (ITO) thin films on polymeric substrates such as acryl (AC), Poly carbornate (PC), polypropylene (PP), and polyethlene terephthalate (PET) have been deposited by a do reactive magnetron sputtering without heat treatments. Sputtering parameters is an important factor for high Qualify of ITO thin films prepared on polymeric substrates. Furthermore, the material, electrical and optical properties of as-deposited ITO films are dominated by the ratio of oxygen partial pressure. As the experimental results the surface roughness of ITO films becomes rough as the oxygen partial pressure Increases. The electrical resistivity of as-deposited ITO films decreases initially, and then increases with the increase of oxygen partial pressure. The optical transmittance at visible wavelength for all polymeric substrates is above 80%.