• The monthly packaging world
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• s.94
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• pp.127-133
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• 2001

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1996.10a
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• pp.115-116
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• 1996

• Korean Journal of Materials Research
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• v.9 no.7
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• pp.724-734
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• 1999

The adhesion characteristics of the thermoplastic resins such as PE, PP PVC, PET and PS were investigated on the surfaces of conventional steel (SS41), steel (SS41P) treated with ultrasonic waves and the SS41P coated with several ceramic powders (SS41PC) by the plasma spray. Alumina (Al$_2$O$_3$), alumina titania (Al$_2$O$_3$95%, TiO$_2$ 5%) and zirconia yttria (ZrO$_2$ 95%, $Y_2$O$_3$5% ) were used for the materials plasma spray The morphologies, surface hardness, surface roughness, and contact angles on SS41, SS41P, and SS41PC were examined. The tensile shear strength and peel strength of the polymers which were attached to the surfaces of ceramics coated on SS41P also were measured. The tensile shear strength and peel strength of polymers adhered to ceramic surface coated on steel were found to be stronger than those of conventional steel. The tensile shear strength and peel strength of the polymers adhered on the surfaces of ceramics coated steel increased in the following order PE > PET > PP > PS > PVC. The high adhesion strength of PE may be attributed to the surface roughness and its anchor effect on the ceramic surface.

• Resources Recycling
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• v.12 no.4
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• pp.44-50
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• 2003

Separation of mixed plastics is not a simple task due to similarities of specific gravity and limitations of sizes, etc. In this study, a new technique was developed to separate plastics selectively by a thermal adhesion method using the different softening or melting temperatures of various types of plastics. Tests were conducted to investigate softening or melting temperatures and adhesion probabilities of plastics with change in temperature. Tests also were conducted to analyze the operating variables, including contact times, size and color pigment. It was founded that LDPE, HDPE and PVC, PET, etc among mixed plastics could be separated selectively according to the change of temperature.

• Korean Journal of Ecology and Environment
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• v.52 no.1
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• pp.28-39
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• 2019

This study was conducted to elucidate microplastics detection of freshwater ecosystems in Geum river. Samples are collected at 6 points in freshwater, 5 points in fishes. Freshwater was sampled 100 L per each points and fish species were Opsariichthys uncirostris amurensis, Hemibarbus labeo, Pseudogobio esocinus, Zacco platypus, Micropterus salmoides and Cyprinus carpio. FTIR analyis was adopted to identify microplastic types. Extracted microplastics were PES (polyester), PE (polyethylene), PP (polypropylene), PET (polyethylene terephthalate), PVC(Polyvinyl chloride) in freshwater, and PES, PE, PP, PET, PVC in fishes. Our results were expected to be used basic research information for further study in microplastics of freshwater ecosystems.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.9
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• pp.1027-1033
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• 2011

A VCM sheet is a metal sheet on which PET/PVC is coated for outer panels of home appliances. The purpose of this study is to obtain methods for suppressing PET tearing that occurs during the press forming of the VCM sheet. In order to identity the factors that minimize PET tearing, an FE analysis was performed. The occurrence of PET tearing cannot be predicted using the conventional forming limit diagram. PET is torn by friction between a die and sheet, which is caused by the thickening of material at a die corner. To reduce the thickening of material, the blank shape was re-designed and the thickened material at a flange was removed by a trimming process. The results of the FE-analysis involving modified process parameters showed that the thickness of the product at a die corner is distributed within the clearance of drawing and flangeforming process. A forming experiment was conducted to verify the proposed process parameters. A good final product was obtained without PET tearing of the VCM sheet.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1583-1584
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• 2011

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.24 no.2
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• pp.41-48
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• 2018

A printable time temperature integrator (TTI) consisting of oxygen indicator and cover films with various oxygen permeability was developed. The printing ink contained methylene blue (oxygen indicator) which changed in color during storage. $TiO_2$ and glycerol for UV-activation of TTI and zein and ethanol for printing performance were also contained in the printing ink. The cover film on the ink was employed to control the color change rate and temperature dependency (Arrhenius activation energy, $E_a$) by using the different films (PE, PET, OPP, and LLDPE). The film properties were varied by annealing. TTI was produced by silk screen printing. As a result, the color change rates were different for the cover films, being the highest in TTI with LLDPE, followed by OPP, PE, and PET. The rate decreased with increase in the cover film thickness. The $E_a$ was the highest in TTI with LLDPE, followed by OPP, PE, and PET. The $E_a$ did not change with the cover film thickness. The annealed PVC and PET film were lower in oxygen permeability than the unannealed ones, indicating the lower color change rate.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.538-543
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• 2000

The purpose of this study is to develope electrostatic separation system for recycling of mixed waste plastics. The electrostatic separation system is designed and investigated the separation efficiency for separating of mixed waste plastics. Electrostatic separation system consisted of a tribocharger, separator (two electrode), collector (5 tray) and controller (positive/negative high voltage power supply). The tribocharger is a fluidized bed using tribo-electrification mechanism between particles and particles. In experimental results, the tribocharger of the fluidized bed was more effective separation efficiency. It showed the purity of $85{\sim}99\;%$ and the recovery of $80{\sim}98\;%$ from the powder of mixed plastics such as LDPE, HDPE, PP, PS, PET and PVC. Especially, In the separation experiment of Polyvinylchloride(PVC) which generates hazardous hydrogen chloride gas in case of the combustion. its purity was over 99 % and recovery was over 95 %.

• Composites Research
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• v.31 no.4
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• pp.122-127
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• 2018

Sandwich composites of carbon fiber reinforced plastic(CFRP) and polymer foam will be used to automobile and aerospace industry according to increasing importance of light weight. In this study, mechanical and heat resistance properties of sandwich composites were compared with type of polymer foam (polyethylene terephthalate(PET), polyvinylchloride(PVC), epoxy and polyurethane). All types of polymer foams were degraded to 30, 60, 120, 180 minutes in $180^{\circ}C$. After heat degradation, the polymer foams were observed using optical microscope and compressive test was performed using universal testing machine(UTM). Epoxy foam had the highest compressive property to 2.6 MPa and after thermal degradation, the mechanical property and structure of foam were less changed than others. Epoxy foam had better mechanical properties than other polymer foams under high temperature. Because the epoxy foam was post cured under high temperature. As the results, Epoxy foam was optimal materials to apply to structures that thermal energy was loaded constantly.