• Journal of the Korean Society of Industry Convergence
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• v.2 no.2
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• pp.69-72
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• 1999

The aim of this study is to enhance the abrasion of the hydrolyzed polyethylene terephthalate(PET) fabrics by using microwave energy. In other to achieve the aforementioned objectives, PET fabrics were hydrolyzed in NaOH solution by using abrasion method such as dipping, microwave-dipping, pad steam-dry, and pad microwave-dry, and then abrasion of the hydrolyzed PET fabrics was calculated and investigated. As a result obtained form this study, the abrasion of the hydrolyzed PET fabrics is directly proportional to hydrolyzed time and NaOH concentration. And also, microwave-dipping method and pad microwave-dry method showed remarkable abrasion effect than the others.

• Korean Journal of Food Science and Technology
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• v.47 no.4
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• pp.425-430
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• 2015

The objective of the study was to investigate the off-flavor generated from PET water bottles and their caps by using a mass spectrometry-based electronic nose. The ion fragment data obtained from the electronic nose were used for discriminant function analysis (DFA). In the case of increased concentrations of the contamination of water, the off-flavor pattern depended on the discriminant function second score instead of the discriminant function first score. To identify the cause of off-flavor in polyethylene terephthalate (PET) bottled water, the PET bottle and its cap were analyzed by DFA. The results showed that the cap generated more volatile compounds than the bottle or mineral water did. The substances causing the off-flavor were predicted to be 2,4-di-tert-butylphenol (2,4-DTBP), nonanal, and decanal when the main peak of the mass spectrum was compared with the major ion fragments of the electronic nose. Thus, using this method, we could determine whether the PET water bottle was contaminated and whether the off-flavor resulted from contamination of the bottle cap.

• Korean Chemical Engineering Research
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• v.61 no.3
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• pp.456-462
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• 2023

An electrically conductive and transparent electrode was created by applying a dispersion of pristine single-walled carbon nanotubes (SWCNTs) and silver nanowires to a polyethylene terephthalate (PET) film using a bar coating method. The SWCNTs were added to increase the electrical conductivity and transmittance of the silver nanowires while also preventing the haze from increasing due to the stacking of multiple layers containing SWCNTs and silver nanowires on the PET substrate. The silver nanowires in the electrode were also found to be stable against oxidation. The transparent electrode displayed excellent electrical and optical properties, with a sheet resistance of 47 Ω/□, transmittance of 96.72%, and haze of 1.93%. Additionally, the sheet resistance of the electrode remained stable over time, with a change of only 6.4% after a constant temperature and humidity test, making it suitable for long-term use. A hybrid transparent electrode that is economically feasible and environmentally sustainable has been developed through the utilization of pristine SWCNT and silver nanowire.

• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.144-150
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• 2013

The kinetics of the transesterification of dimethyl terephthalate (DMT) with ethylene glycol (EG) was studied in a batch reactor. Bishydroxyethyl terephthalate (BHET), which is poly(ethylene terephthalate) (PET) monomer, can be produced by the transesterification reaction. Zinc acetate was used as a catalyst. Previous kinetic studies was carried out in a semi-batch reactor where generated methanol was removed so that reverse reactions were not considered in the kinetic expressions, resulting in inaccuracy of the kinetic model. Mathematical models of a batch reactor for the tranesterification reaction were developed and used to characterize the reaction kinetics and the composition distribution of the reaction products. More accurate models than previous ones were obtained and found to have a good agreement between model predictions and experimental data. Effect of process variables on the esterification reaction was investigated based on the experimental and simulation results.

• Laser Solutions
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• v.6 no.2
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• pp.35-41
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• 2003

In this study, manufacturing of polymer master and mold insert for micro injection molding was investigated. Ablation by excimer laser radiation could be used successfully to make 3-D microstructure of PET. The mechanism for ablative decomposition of PET with KrF excimer laser(λ: 248nm, pulse duration: 5ns) was explained by photochemical process. And this process showed PET to be adopted in polymer master for nickel mold insert. Nickel electroforming by using laser ablated PET master was preferable for replication method. Finally, it was shown that excimer laser ablation can substitute for X-ray lithography of LIGA process in microstructuring.

• Fibers and Polymers
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• v.7 no.4
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• pp.446-449
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• 2006

The purpose of this study was to evaluate the comfort of PET clothing treated by UV. The physiological responses of the human body were investigated. Mean skin temperature and physiological signals such as Electroencephalogram (EEG), and heart rate (Electrocardiogram, (ECG)) were examined for 20 minutes during stable wearing conditions. Mean skin temperature was measured every two seconds using Ramanathan's method. Physiological responses were measured using Biopac MP100 series and analyzed using the software, Acqknowledge 3.5.2. Psychological effects were analyzed every five minutes. Comfort of untreated PET clothing decreased with the passage of time. Compared with PET clothing untreated, treated for 30 minutes, and treated for 90 minutes, the analysis of EEG showed that PET clothing treated for 90 minutes was the most comfortable after 20 minutes. In addition, the interval of the heart rate shown on the ECG was the highest in PET clothing treated for 90 minutes. Skin temperature was the lowest in PET treated for 90 minutes. We thus conclude that suitable UV irradiation would improve comfort.

• Fibers and Polymers
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• v.7 no.4
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• pp.339-343
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• 2006

The aim of this paper is to improve moisture regain of PET fabrics using a lipase treatment. Effects of nine lipase sources, lipase activator and nonionic surfactant on moisture regain of PET fabrics are examined. Moisture regains of lipase-treated samples improve by two times in average compared with untreated and buffer-treated samples. Alkaline treatment creates larger pitting by more aggressive attack into fiber which is proved by SEM and water contact angle measurement. Moisture regain by alkaline treatment ($0.568%{\pm}0.08$) does not improve. However, lipase-treatment (L2 treatment) improves moisture regain up to 2.4 times ($1.272%{\pm}0.05$). Although lipase treatment is more moderate than alkaline treatment, lipase hydrolysis on PET fabrics improves moisture regain, efficiently. K/S values improved confirm that carboxyl and hydroxyl groups are produced on the surface of PET fabrics by lipase hydrolysis. Moisture regain and dyeability improve by lipase hydrolysis on PET fabrics.

• Laser Solutions
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• v.6 no.1
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• pp.33-40
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• 2003

The ablative decomposition mechanism of PMMA(polymethyl methacrylate) and PET(polyethylene terephthalate) with KrF excimer laser(λ : 248nm, pulse duration: 5㎱) is investigated. The UV/Vis spectrometer analysis showed that PMMA is a weak absorber and PET is a strong absorber at the wavelength of 248nm. The results(surface debris, melt, etch depth, etching shape) from drilling and direct writing experiments imply that ablation mechanism of PMMA is dominated by photothermal process, while that of PET is dominated by photochemical process.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.373-376
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• 2006

The purpose of this study was manufactured and evaluated the bond performance of recycled polyethylene terephthalate(PET) bottle fiber reinforced concrete. Four deformed recycled PET bottle fibers were manufactured and pullout test was conducted in accordance with the JCI-SF 8. Test parameters included four different type of fiber geometry and two types of mortar specimens. According to bond test results, it was found that embossing type recycled PET bottle fiber was significant improving the pullout load and interface toughness.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.727-729
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• 2001

The air separation of PET (Polyethylene terephthalate) and PS(Polystyrene) was carried out by taking advantage of the different abrasive resistance of two plastics. PET bottles and PS packages were shredded to small square pieces $(5{\times}5mm)$. Both plastic shreds were treated by a shear-type crusher. The PET shreds were bent and twisted by the crush so that they were blown up easily, but the PS shreds were not. After the crush of mixture of both plastics, air separation experiments were carried out using four types of air separators. The number and location of the baffle attached to them are different. With the separator with a baffle attached at the upper part, PET recoveries for the crushing time of 30, 60 and 90sec were 67, 98 and 99% respectably at the air flow rate of 3.5m/s, whereas PS recoveries were null regardless of the crushing time.