• Macromolecular Research
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• v.11 no.5
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• pp.387-392
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• 2003

The ablation effects of Ar-plasma treatment and alkali-decomposition behavior in NaOH solution of polyethylene terephthalate (PET) film were investigated. The modifications were evaluated by analysis of atomic force microscopy topographical changes, and by the measurement of decomposition yield in conjunction with heats of formation and electron densities of acyl carbon calculated by Parameterization Method 3 method. It has shown that the alkali-decomposition is hampered by plasma treatment and its decomposition yield is closely related with plasma treatment conditions such as exposure time to plasma. Plasma-treated PET films exhibited lower decomposition yield, compared to that of virgin PET. Increasing plasma exposure time contributes positively to decrease the decomposition yield. It has also shown that the topography of PET surface was affected by the base-promoted hydrolysis as well as Ar-plasma treatments. These behaviors are attributed to the decreased nucleophilicity of acyl carbon damaged by the ablation of Ar-plasma.

• Textile Coloration and Finishing
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• v.14 no.5
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• pp.268-276
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• 2002

Poly(trimethylene terephthalate)(PTT) and Poly(ethylene terephthalate)(PET) fibers were annealed at various temperatures ranging from $100^\circ{C}$ to $230^\circ{C}$ for 10 min under tension and tension free. Dyeing rates and absorption isotherms of both fibers were obtained with C.I. Disperse Red 60 at 100, 120 and $130^\circ{C}$ in water system. Also X-ray diffraction pattern, moisture regain and water absorption were investigated. The dyeing rate of PTT fiber is faster than PET fiber, and dyeing of PTT fiber begin at lower temperature compared to PET fiber. The absorption isotherms from both fibers with disperse dye we nearly linear up to the saturation dye uptake, which increase with dyeing temperature. Equilibrium dye uptake of PTT fiber annealed under tension above $180^\circ{C}$ was remarkably decreased because of a changes in the fine structure of fiber. The intensities of X-ray diffraction peaks of both annealed fibers were increased with increasing in annealed temperature. The reflections observed at $2\theta$=$15.8^\circ$, $24^\circ$ and $25.2^\circ$ were assigned reflection of crystal at the planes of (010), $(1\bar02,\;\bar112),\;and\;(\bar13,\; \bar113)$ respectively, and the peak became sharp with heat setting temperature.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.11
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• pp.1880-1888
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• 2010

This study was a preliminary investigation of the influence of surface characteristics of substrates on the detergency of particulate soil. A PET film was surface modified with NaOH and DMF for different times. The surface morphology of the film was scanned by AFM and the surface energies were calculated from the measured contact angles between several solutions and film based on a geometric mean and the Lewis acid base method. The surface morphology of the PET film treated with NaOH and DMF became more etched and swelled with an increased treatment time, respectively. The surface roughness and surface area of film treated with NaOH enlarged with increased treatment time. However, the coefficient of friction of film treated with NaOH and coefficient of friction, surface roughness, and surface area of film treated with DMF increased and then decreased with increased treatment time. The contact angle of film treated with DMF decreased with increased treatment time in water and surfactant solution; however, the effect of treatment time on the contact angle was different in both solutions for film treated with NaOH. By the treatment of PET film with NaOH and DMF, the polar group of the surface energy increased and the nonpolar group decreased; however, the change of total surface energy was not significant.

• Polymer(Korea)
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• v.26 no.3
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• pp.389-399
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• 2002

Poly (ethylene terephthalate) (PET) fibers were modified by deep UV irradiation which was produced by a low pressure mercury lamp. FT-IR and XPS analyses were used to elucidate the surface chemical composition of PET fibers treated with UV. Relative $O_{1s}$ intensity increased considerably and it was found that oxygen was incorporated in the form of COO on the fiber surface. FT-IR and XPS analyses proved the existence of carboxylic groups on the surfaces and the adsorption test of cationic compound further supported these results. The concentration of carboxylic acid group on the surface increased remarkably with Increasing irradiation time. XPS analysis and adsorption experiments proved that the surface structure of the UV-irradiated PET fibers were stable for 12 months. Antibacterial property and the deodorization rate of UV-irradiated PET fibers adsorbed with the berberine compound were investigated. Reduction rates of bacteria increased by about 21 to 99% compared to unradiated PET fiber. Deodorization rates of 23% for unradiated PET fiber increased to about 75% for 30 min irradiated samples.s.

• Polymer(Korea)
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• v.26 no.3
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• pp.335-343
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• 2002

Blend resin (PET/PETG 70/30 blend) of poly (ethylene terephthalate) (PET) and poly (ethylene terephthalate glycol) (PETG) of weight percent 70/30 was prepared by a twin-screw extruder. Undrawn films of the blend and pure PETG were made by melt-press in hot press. Drawn films were made by capillary rheometer. Crystallinity, shrinkage, thermal, dynamic mechanical, and mechanical properties of these blends and PETG drawn films were investigated by wide angle X-ray diffractometer, dry oven, DSC thermal analyzer, and tensile tester. The crystallinity and density of these films increased with increasing draw ratio and draw rate but decreased with increasing draw temperature. The crystallinity and density of the blend films were higher than those of PETG films. The tensile strength and tensile modulus of these drawn alms increased with increasing draw ratio and draw rate but decreased with increasing draw temperature. The tensile strength and tensile modulus of blend films were higher than those of PETG films. Shrinkage of PETG md blend films decreased with draw ratio and draw rate. Shrinkage of undrawn blend film was 600% higher than that of pure PET film.

• Applied Chemistry for Engineering
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• v.8 no.1
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• pp.76-83
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• 1997

Blends of thermotropic liquid crystalline polymer(TLCP) with poly(ethylene terephthalate) (PET) were prepared by the coprecipitation from a common solvent. The blends were processed through a capillary die at $287^{\circ}C$ to produce a monofilament. Morphology and mechanical, thermal properties of blends and composites were examined by differential scanning calorimetry(DSC), tensile test, optical microscopy and scanning electron microscopy. Crystallization kinetics of the blends were investigated by the isothermal DSC method. The Avrami analyses were applied to obtain the information on the crystal growth geometry and factors controlling the rate of crystallization. In the blends, liquid crystalline phase did not reveal any significant macrophase separation and thermal degradation at the processing temperature. From scanning electron micrographs of cryogenic fracture surfaces of extruded fibers, the TLCP domains were found to be more or less finely dispersed with $0.1{\mu}m$ to $0.2{\mu}m$ in size. Interfacial adhesion between the TLCP and matrix polymer was excellent. Tensile strength and modulus of TLCP/PET in-situ fiber composites were enhanced with increasing draw ratio and LCP content.

• Korea-Australia Rheology Journal
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• v.13 no.4
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• pp.169-177
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• 2001

Morphological, thermal, rheological, and mechanical properties of reactive compatabilized blends of poly(butylene terephthalate) (PBT) and Polyamide-6 (PA) containing EGMA copolymer were investigated using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), advanced rheometric expansion system (ARES), and universal testing machine (UTM). From the results of thermal analysis by DSC, the melting point of the 30/70 PBT-PA blend was broadened after EGMA was added in the blends, since the enthalpy of melting of the PBT-PA somewhat decreased with the increase of EGMA content. From this result, it is suggested that the EGMA affected to the crystallization behavior and crystallinity of the PBT-PA blends. From SEM micrographs of the 70/30, 50/50, and 30/70 PBT-PA blends, the droplet size of the 30/70 PBT-PA blend was about 0.8 ${\mu}{\textrm}{m}$ which was smaller than that of the 50/50 and 70/30 PBT-PA blends. The complex viscosity of the 30/70 PBT-PA blend observed to be higher than that of the 50/50 and 70/30 PBT-PA blends. From the results of the morphology and rheological properties for the PBT-PA blends, it is suggested that the compatibility is increased in the 30/70 PBT-PA blend than the 50/50 and 70/30 PBT-PA blends. From the results of mechanical properties, it was found that the tensile strength of the 30/70 PBT-PA blend increased with the increase of EGMA up to 2 phr, while tensile strength of the blend in which EGMA content was higher than 2 phr decreased with the increase of EGMA content. From the results of morphological, thermal, rheological, and mechanical properties for the PBT-PA-EGMA blends, it is suggested that the EGMA could be used as a compatibilization role in the blends.

• Membrane Journal
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• v.25 no.3
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• pp.287-294
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• 2015

Photovoltaic (PV) modules are environmentally friendly energy-conversion devices to generate electricity via the photovoltaic effect of semiconductors on solar energy. One of key elements in PV modules is "Backsheet," a multi-layered film to protect the devices from a variety of chemicals including water vapor. A representative Backsheet is composed of polyvinyl fluoride (PVF) and poly(ethylene terephthalate) (PET). PVF is relatively expensive, while showing excellent resistance to chemical attacks. Thus, it is necessary to develop alternatives which can lower its high production cost and guarantee lifetime applicable to practical PV modules at the same time. In this study, PET films with certain levels of crystallinity were utilized instead of PVF. Since it is well known that PET is suffering from trans-esterification and hydrolysis under a wide pH range, it is needed to understand decomposition behavior of the PET films under PV operation conditions. To evaluate their chemical decomposition behavior within a short period of times, accelerated decomposition test protocol is developed. Moreover, electrochemical long-term performances of the PV module employing the PET-based Backsheet are investigated to prove the efficacy of the proposed concept.

• Textile Coloration and Finishing
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• v.21 no.1
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• pp.30-37
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• 2009

Studies on plants such as lotus leaf suggested that dual-scale structure could contribute to super-hydrophobicity. We introduced super-hydrophobicity onto poly(ethylene terephthalate)(PET) fabric with dual-scale structure by assembling $TiO_2$ nano sol. PET fabric was treated with $TiO_2$ sol, water-repellent agent using various parameters such as particle size, concentration. Morphological changes by particle size were observed using field emmission scanning electron microscopy(FE-SEM) and AFM measurement, contact angle measurement equipment. The contact angle of water was about 138.5$^{\circ}$, 125.8$^{\circ}$, 125.5$^{\circ}$ and 108.9$^{\circ}$ for PET fabric coated with 60.2nm, 120.1nm, 200nm and 410.5nm $TiO_2$ particles, compared with about 111.5$^{\circ}$ for PET fabric coated with water repellent. When we mixed particle sizes of 60.2nm and 120.1nm by 7:3 volume ratio, the contact angle of water was about 132.5$^{\circ}$. And we mixed particle sizes of 60.2nm and 200nm by 7:3 volume ratio, the contact angle of water was about 141.8$^{\circ}$. Also we mixed particle sizes of 60.2nm and 410.5nm by 7:3 volume ratio, the best super-hydrophobicity was obtained. In this paper, we fabricated various surface structures to the water-repellent surfaces by using four types of $TiO_2$ nano-particles, and we found that the nanoscale structure was very important for the super-hydrophobicity.

• Korean Chemical Engineering Research
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• v.40 no.6
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• pp.709-714
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• 2002

To investigate the decomposition kinetics of poly(ethylene terephthalate) the high pressure molten-polymer injector has been devised. Using the experimental apparatus equipped with batch reactor and high pressure molten-polymer injector the decomposition of PET has been performed at constant pressure of 250 bar and 300, 320, $340^{\circ}C$, respectively. At each temperature conditions the conversions after initial 1 minute have shown very high values such as 76-90%. As the temperature increases the conversion reaches more than 98% at 10 minutes. Based on the second order reaction model the reaction rate constants have been obtained. We can calculate the conversions within 2% errors utilizing optimized rate constants. The activation energy for the decomposition of PET at subcritical conditions has shown to be 54.4 kJ/mol.