• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.199-199
• /
• 2012

최근 그래핀의 대면적 합성 및 롤투롤 전사 공정의 개발로 그래핀의 상용화가 가시화 되고 있다. 하지만, 그래핀의 독특한 특성인 선형적이고 밴드갭이 없는 에너지 띠 분포 때문에 반도체 소자로서의 직접적인 적용에는 한계가 있다. 이러한 문제를 해결하기 위한 돌파구로써, 그래핀 복합체의 연구와 개발이 활발히 진행되고 있으며 본 연구에서는 그래핀 복합 적층 구조를 다룬다. 이는 디스플레이, 초고속 반도체 소자, 고성능 광전자소자 및 초고감도 센서 등 다양한 분야에 대한 그래핀의 실용화 가능성이 높아진 것을 의미한다. 특히, 높은 가시광 투과도와 낮은 면저항으로 기존 투명 전극에 대표적으로 사용되고 있는 ITO (Indium Tin Oxide)를 그래핀으로 대체하는 것에 관한 연구가 활발히 진행되고 있다. 하지만 그래핀이 높은 전자이동도를 가지는 것에 비하여 비저항과 투과도 측면에 있어서는 ITO의 성능을 뛰어넘지 못하는 실정이다. 따라서 본 연구에서는 ITO가 가지는 취약점인 기판과의 약한 접착력, 높은 취성, 기판과의 열팽창률 차이 등의 공정상 문제점을 극복하고자 하였다. 그래핀 복합 적층 필름은 플라스틱 기판 (PET) 위에 열 화학기상증착법(Chemical Vapor Deposition, CVD)을 이용하여 합성한 그래핀을 전사하고, ITO 용액을 도포한 다음 다시 그래핀을 씌워 제작하여 샌드위치 구조(sandwich structure)를 형성하였다. 완성된 필름은 광학적, 전기적 특성 분석을 수행하였다. 광학적 분석으로는 라만 분광을 이용한 그래핀 품질평가와 파장대에 따른 광 투과도, 그리고 반사도 측정을 하였으며, 전기적 특성은 면저항을 측정함으로써 분석한다. 결함이 적고, 대면적에 걸쳐 한 층을 이루어야 하는 고품질 그래핀의 요구사항에 따라 라만 분광의 G, 2D, D 띠를 분석하였다. G와 2D 띠의 비율을 통해 그래핀의 층 수를, D 띠의 강도를 통해 결함의 유무를 판단하였다. 또한, 가시광 영역에서 90% 이상의 광 투과도를 보여야 하는 투명 소자의 요구사항 달성 정도를 UV-VIS를 이용하여 확인하였다. 마지막으로, 제작한 필름의 면저항 또한 4-프로브 멀티미터를 이용하여 측정하고, 일반적인 터치스크린의 면저항인 $500{\Omega}/sq$를 만족하는지 평가하였다.

• Polymer(Korea)
• /
• v.27 no.6
• /
• pp.549-554
• /
• 2003

Emeraldine salt of polyaniline-dodecylbenzenesulfdnic acid (PANI-DBSA) in organic solvents such as toluene and xylene was obtained by a direct one-step emulsion polymerization technique. When the molar ratio of DBSA to aniline monomer was 1.5:1, its solubility and electric property showed a maximum value and then the solid contents of PANI-DBSA was 8 wt% in toluene. The cast film of PANI-DBSA with no binder was obtained on glass or plastic substrates under ambient conditions. PANI solution can be also easily blended with polyurethane and polystyrene polymers in toluene. Improved electrical performance up to 5 S/cm was achieved with good light-transmittance up to 70% at 500 m thickness. They also showed more homogeneous morphology than that prepared with PANI-DBSA kom aqueous dispersion polymerization. The partially dispersed PANI-DBSA showed particles sizes of 50-400 m in organic solvents and their XRD pattern were observed from the powder sample.

• Analytical Science and Technology
• /
• v.19 no.5
• /
• pp.389-393
• /
• 2006

The detector consisted of ZnS(Ag) scintillator and photomultiplier tube (PMT) is widely used as contamination monitor in the nuclear facilities. Such detectors are mainly manufactured by adhering the ZnS(Ag) powder onto the transparent plastic. In this study the preparation condition for ZnS(Ag) scintillator sheet using a simple method was established. The scintillator sheet was composed with a support polymer sheet and ZnS(Ag) scintillator layer. The base sheet was prepared by casting the polymer solution after solving the polymer with solvent and the scintillator layer was manufactured by printing the mixture solution with ZnS(Ag) and paste. It was found that the polysulfone(PSf) as a polymer for the base sheet and a cyano resin as a paste for adhering the ZnS(Ag) scintillator was suitable. Also, the prepared thin scintillator sheet had a sufficient mechanical strength, a optical transparency and an alpha-ray detection performance.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.69 no.2
• /
• pp.123-132
• /
• 2024

In this study, two types of biodegradable film prototypes were produced using plastic resin containing rice powder. The application of these biodegradable films in sweetpotato (Ipomoea batatas L. Lam) fields and their impacts of plant growth, yield, and the soil environment were assessed, in comparison with Polyethylene (PE) film. The light transmittance of the biodegradable film containing 30% of 350 mesh rice powder (BF30-350RP) was 0.8%, which was lower than the 2.0% light transmittance of the biodegradable film containing 40% of 500 mesh rice powder (BF40-500RP) and 2.7% light transmittance of PE film. Surface temperature measurements on clear day indicated that the PE film exhibited the lowest temperature, with the minimal difference observed between BF40-500RP and BF30-350RP. Assessment of the damage ratio resulting from agricultural work revealed a ranking of 0.4% for the PE film, 3.3% for BF500-400RP, and 5.3% for BF350-30RP. Visible decomposition of BF40-500RP and BF30-350RP commenced after 40 and 30 days of outdoor exposure, reaching 62.3% and 70.4% decomposition at 90 days post-exposure, respectively. The decomposition of biodegradable films applied to sweetpotato fields progressed more slowly in BF40-500RP than in BF30-350RP. The BF40-500RP film on the surface of the ridges was decomposed by 5%, 30%, 55%, and 90% after 30, 60, 90, and 120 days after planting sweetpotato cuttings, respectively. Both types of biodegradable films at the ridge and furrow borders were completely decomposed after 75 days of sweetpotato planting. In a field where the surface was sealed by mulching without growing sweetpotatoes, the soil moisture and its deviation were lower in the order of PE film, BF40-500RP, and BF30-350RP, but the differences were not significant. The soil temperature was higher for PE film mulching than for the biodegradable films containing rice powder, but the differences were small. Two months after sweetpotato planting, the daily average soil moisture decreased by 2.5%point for BF30-350RP mulching, 1.5%point for BF40-500RP mulching, and 1.1%point for PE film mulching over seven days. Soil temperature was similar for both biodegradable film mulches, but increased steadily for the PE film mulch, reaching a daily average of 0.1℃ higher than for the biodegradable films. Sweetpotato vine growth and tuber yield were similar for all the mulching films tested.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.8 no.2
• /
• pp.49-59
• /
• 2002

The main function of plastic materials in food packaging is to preserve a food for safe transportation and storage. The interactions between food and plastic materials in food packaging have become increasingly important for food quality and safety because monomer, low molecular weight components, or additives of plastic packaging materials can migrate into a food. The use of antioxidants in plastic materials can help protect the degradation of film itself and retard the oxidation of a packaged food containing lipid, through the migration of antioxidant from the packaging to a product via an evaporation / sorption mechanism. Nowadays, antioxidant (BHT) impregnated plastic materials are used for commercial food packaging application with the intention of achieving an extended shelf life of food in USA. Alpha tocopherol, as one of the most important free radical scavengers, has been well known in biological systems. Moreover, the potential use of alpha tocopherol as an additive for polymers used in the packaging industry may offer the most positive perception from both consumers and manufacturers. Alpha tocopherol has been used as an antioxidant for polyolefin resins fabricated to both bottles and film and has applications in the food packaging industry as a replacement for BHT. Today, alpha tocopherol offers an attractive choice for use as an antioxidant in polymers. This paper provides an overview of antioxidant effectiveness and applications for its use by the food packaging industry based on the evaporation-sorption mechanism of a packaging model product, where quality is associated with lipid oxidation. Important analytical techniques for predicting antioxidant interaction between the package system and product are discussed.

• Polymer(Korea)
• /
• v.30 no.2
• /
• pp.140-145
• /
• 2006

The mort commonly available substrate material is glass in the display fibrication process. However, glass is not desirable due to its heaviness and fragility. Recently, plastics such polysulfone (PSF), polyethesulfone (PES), polycarbonate (PC), polyethylene terephthalate (PET) and cyclic olefin polymers (COP) have been investigated to replace glass as a substrate material for display fibrication. Plastic substrates are advantageous in that they are lightweight, huh impart resistance, flexibility, and ability for roll to roll manufacturing process. But many plastics have poor chemical resistance in organic solvent. The chemica resistance is also lequired because they are exposed to solvents for various chemical treatments din the manufacturing process. So, we have an interest in the chemical modification of PSF to improve chemical resistance. We introduced crosslinkable imide moieties using chloromethylation method for the modification of PSF which could be overcome above shortcomings for display substrate based on plastic film. We prepared the cross-linked polysulfone films which were represented chemical resistance in HeOH, THF, DMSO and NMP. The thermal properties were measured by TGA, DSC and TMA. As the results, we have confirmed to enhance of the thermal property. They had low coefficient of thermal expansion (CTE) which decreased to 15% and had increased $T_g\;from\;180^{\circ}C\;to\;252^{\circ}C$. Cross-linked polysulfone films with imide side-chain had good optical properties and chemical resistance so that they could be used as flexible display substrate.

• Korean Journal of Food Science and Technology
• /
• v.35 no.1
• /
• pp.149-154
• /
• 2003

Changes in mineral (Ca, Mg) contents and pectic substances of mature-green 'Nanko' Mume fruits hermetically packaged in 0.03 mm low density polyethylene (LDPE) films with and without gas absorbents were examined during storage at $25^{\circ}C$ for 10 days. Each packaging contained 10 g $Ca(OH)_2$ as a carbon dioxide scavenger, 30 g $KMnO_4$ as an ethylene scrubber or their mixture. In the presence of the ethylene scrubber, losses in mineral contents of alcohol insoluble solids and water soluble pectin were remarkably suppressed, whereas no significant difference was observed in the Ca content between the fresh fruit and those stored for 10 days. Fruits packaged with the ethylene absorbent retained higher amount of pectic substances than those with other packaging treatments. Degradation of the pectic substances into small molecules was also noticeably reduced when the ethylene scrubber was used. Overall results showed that the combination of the gas permeable film and the ethylene absorbent could be applied to mature-green Mume fruits as an effective packaging method to retard the texture softening during storage at the ambient temperature.

• Journal of Bio-Environment Control
• /
• v.27 no.2
• /
• pp.180-184
• /
• 2018

This study was conducted to examine the effect OTR film type on the quality of garden cress (Lepidium sativum L.) baby leaf during MA storage. Garden cress harvested at baby leaf size of 10cm plant height packed with 1,300 cc, 10,000 cc, 20,000 cc, 40,000 cc, and $80,000cc{\cdot}m^{-2}{\cdot}day^{-1}{\cdot}atm^{-1}$ OTR (oxygen transmission rate) films and MP (micro-perforated) film, and then stored at $8^{\circ}C$ for 10 days. All of the OTR film treatments showed a decrease of 0.5% fresh weight until the storage end date and a 1.3% decrease in the MP film treatment. The oxygen concentration in the packaging during storage was maintained at 18% or more in 20,000 cc, 40,000 cc, and 80,000 cc OTR film treatments, while the 1,300 cc OTR film treatment decreased to 11% at the storage end date. And the concentration of carbon dioxide was steadily increased in the 1,300 cc and 10,000 cc OTR film treatments to show the levels of 4.5% and 3.4%, respectively, and the other OTR film treatments showed a concentration of less than 1%. Ethylene concentration in the package was maintained at the highest level of $3-5{\mu}L{\cdot}L^{-1}$ in the 1,300 cc treatment during the storage period. The lowest odor and the highest quality of appearance were observed in the 1,300 cc treatment, but the MP film treatment and the other OTR treatments lost marketable quality due to yellowing. The color of garden cress baby leaf was changed the lowest in 1,300 cc treatment that showed the highest chlorophyll content and Hue angle value, lowest $b^*$ value, present of yellowing at end of storage date. Therefore, 1,300 cc treatment which was most effective for yellowing and odor suppression during storage is considered to be suitable for packaging of garden cress baby leaf.

• Journal of radiological science and technology
• /
• v.28 no.1
• /
• pp.9-12
• /
• 2005

In this study, film type radiation sensor tips are fabricated for remote sensing of X or g-ray with inorganic scintillators and plastic optical fiber. The visible range of light from the inorganic scintillator that is generated by X and g-ray is guided by the plastic optical fiber and is measured by optical detector and power-meter. It is expected that the fiber-optic radiation sensor which is possible to be developed based on this study is used for remote, fast and exact sensing of X or g-ray because of its characteristics such as very small size, light weight and no interference to electromagnetic fields.

• Resources Recycling
• /
• v.27 no.4
• /
• pp.3-15
• /
• 2018

Since the use of plastics in various goods such as film, containers, and packaging has been increasing in Korea, the generation of plastic waste is increasing. Plastic wastes are managed by waste charge system, Extended Producer Responsibility (EPR) system and voluntary agreement of plastic waste collection-recycling system. Recently, the management of plastic waste is becoming a social issues due to the refusal of the collection of plastic waste including waste plastic bag and waste vinyl. The ministry of environment in korea was set up the comprehensive plan for recycling waste management in accordance with the circulation cycle of manufacturing and production - distribution and consumption - separate and discharge - collection and sorting - recycling. In this study, the improvements for management of plastic waste were suggested with the review of domestic waste plastics management and the comprehensive plan by the ministry of environment.