• Journal of the Korean Chemical Society
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• v.20 no.2
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• pp.141-145
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• 1976

Although teflon(PTFE) is quite stable at the normal fabrication temperature of 330 to 360$^{\circ}C$, it does undergo pyrolysis if it is maintained at temperature above 360$^{\circ}C$ for extended periods of time. The extent and rate of this pyrolysis increases as the temperature is raised and pressure is reduced. The pyrolysis was also carried out in the presence of copper, no significant change was observed.

• 대한방사선방어학회:학술대회논문집
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• 2009.11a
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• pp.174-175
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• 2009

• Proceedings of the Korean Vacuum Society Conference
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• 2002.06a
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• pp.176-176
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• 2002

• Journal of the Microelectronics and Packaging Society
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• v.11 no.1
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• pp.21-28
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• 2004

We have demonstrated the applicability of dry film photoresist (DFR) in photolithography process for fine pitch solder bumping on the polytetrafluoroethylene (PTFE/Teflon ) printed circuit board (PCB). The copper lines were formed with 100$\mu\textrm{m}$ width and 18$\mu\textrm{m}$ thickness on the PTFE test board, and varying the gaps between two copper lines in a range of 100-200$\mu\textrm{m}$. The DFRs of 15$\mu\textrm{m}$ thickness were laminated by hot roll laminator, by varying laminating temperature from $100{\circ}C$ to 15$0^{\circ}C$ and laminating speed from 0.28-0.98cm/s. We have found the optimum process of DFR lamination on PTFE PCB and accomplished the formation of indium solder bumps. The optimum lamination condition was temperature of $150^{\circ}C$ and speed of about 0.63cm/s. And the smallest size of indium solder bump was diameter of 50$\mu\textrm{m}$ with pitch of 100$\mu\textrm{m}$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.1
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• pp.58-63
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• 2005

PTFE (polytetrafluoroethylene) thin films were prepared from the pellets of the graphite doped PTFE via pulsed laser ablation with 1064 nm Nd:YAG laser. The graphite powder converts the absorbed photon energy into thermal energy which is transmitted to nearby PTFE. The PTFE is decomposed by thermal process. The deposited films were transparent and crystalline. SEM (scanning electron microscopy) and AFM (atomic force microscopy) analyses indicated that the film surface morphology changed to fibrous structure with increasing thickness. The fluorine to carbon ratios of the film were 1.7 and molecular axis was parallel with (100) Si-wafer substrate. These results obtained by XPS (X-ray photoelectron spectroscopy), FTIR (fourier transform infrared spectroscopy) and XRD (X-ray diffraction).

• Elastomers and Composites
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• v.45 no.1
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• pp.32-39
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• 2010

The mechanical properties of PTFE 100%, PTFT 90% + carbon black 10%, PTFE 85% + glass fiber 15%, PTFE 80% + glass fiber 15% + molybdenum disulfide ($MoS_2$) 5%, PTFE 75% + glass fiber 25%, and PTFE 75% + carbon black 18% + graphite 7% composites were investigated in this study. The differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to examine the heat of fusion(${\Delta}H_f$) and thermal stability of the composites. Also, the wear surface and wear volume of PTFE lip seal were examined using the durability test. Wear surface was observed using scanning electron microscope (SEM). It was found that the hardness, wear resistance and durability were enhanced by adding glass fiber and molybdenum disulfide into pure PTFE, but tensile strength and elongation were decreased. According to the experimental results, the composite (PTFE + 15% glass fiber + 5% molybdenum disulfide) showed the best properties for applying to oil-seal among six types of PTFE composites.

• Korean Journal of Materials Research
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• v.16 no.6
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• pp.367-372
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• 2006

Polytetrafluoroethylene (PTFE) surface was modified for improving hydrophilicity by ion irradiation in environmental gas of $N_2$ and $NH_3$, respectively. The water contact angle onto the PTFE surface increased from $104{\circ}$ to over $140{\circ}$ by Ar ion irradiation in $N_2$ gas. In the case of $NH_3$ as environmental gas, there were a slight increase of contact angle from ion dose of $1{\times}10^{15}\;to\;5{\times}10^{15}\;ions/cm^2$, and its dramatic decrease to the value of 35o at the conditions of ion dose higher than $1{\times}10^{16}\;ions/cm^2$. It was found from SEM results that the surface morphology of PTFE was changed into one with filament structure after Ar ion irradiation in $N_2$ gas environments. On the contrary, Ar ion irradiation in $NH_3$ gas condition induced the PTFE surface with network structure. Hydrogen ion irradiation resulted in a little change of PTFE surface morphology, comparing with the case of Ar ion irradiation. The water contact angle of hydrogen ion irradiated PTFE surface in reactive gas decreased with increment of ion dose. Hydrogen ion irradiation could improve hydrophilicity with little change of surface morphology. It might be considered from FT-IR results that the improvement in wettability of PTFE surface by ion irradiation in $N_2$ and $NH_3$ gases could be due to the hydrophilic groups of NHx bonds.

• Journal of Chest Surgery
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• v.19 no.1
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• pp.50-57
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• 1986

Sixty-nine patients with various types of cyanotic congenital heart disease underwent systemic-pulmonary artery shunts with a microporous polytetrafluoroethylene [PTFE] prosthesis between 1979 and 1985. Their ages ranged from 2 months to 39 years [mean$\pm$SD: 5.2$\pm$7.4, median: 3.3 years]. Diagnosis included the following: Tetralogy of Fallot, 45: Double outlet right or left ventricle, 11: Single ventricle, .5: Transposition of great vessels, 4: Tricuspid atresia, 3 and Pulmonary atresia with intact ventricular septum, 1. Forty-eight patients had subclavian-pulmonary artery anastomosis, 12 patients aorta-right pulmonary artery anastomosis, 6 patients aorta-main pulmonary artery anastomosis, and 3 patients descending aorta-pulmonary artery anastomosis. The PTEE graft of 3 mm in diameter was used in 1, 4 mm in 29, 5 mm in 35 and 6 mm in 4 patients. Ten patients were died within 30 days after operation [mortality rate: 14.5%]. Among them, 6 patients were operated in urgency due to cardiac arrest or severe anoxic spell after cardiac catheterization, and so surgical mortality of elective operation is 9.5%. The 59 survivors showed improvement of the arterial oxygen saturation [65.4% - 9.8%] and hemoglobin [18.8 gm/dl - 16.0 gm/dl] values [V<0.01]. The follow up period ranged from 1 month to 67 months, [752 patient-months] and during this periods there were 4 late shunt failures after 3 months postoperatively with 4 mm graft, and 2 with 5 mm graft. The over-all patency rate of 4 mm PTFE was 85.9$\pm$9.2% [SEM] in 12 months and 40.9$\pm$22.5% in 24 months. The over-all patency rate of 5 mm PTFE was 87.5$\pm$9.6% in 12 months and 58.3$\pm$24.6% in 36 months. The lowest systolic pressure in death group was 64.9$\pm$15.0 mmHg and in survival group, 86.4$\pm$12.1 mmHg [P<0.001]. We think that the PTFE graft is useful in palliative shunt operation, but the effectiveness of the 4 mm PTFE graft may be limited. The blood pressure also may play an important role in patency of Prosthesis.

• Membrane Journal
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• v.33 no.4
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• pp.201-210
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• 2023

Dust filter membranes play a crucial role in human life and various industries, as they contribute to several important aspects of human health, safety, and environmental protection. This study presents the development of a polysulfone@polyphenylene sulfide/polytetrafluoroethylene (PSf@PPS/ePTFE) composite dust filter membrane with excellent thermal stability and adhesion properties for high-temperature conditions. FT-IR analysis confirms successful impregnation of PSf adhesive onto PPS fabric and interaction with ePTFE support. FE-SEM images reveal improved fiber interconnection and adhesion with increased PSf concentration. PSf@PPS/ePTFE-5 exhibits the most suitable porous structure. The composite membrane demonstrates exceptional thermal stability up to 400℃. Peel resistance tests show sufficient adhesion for dust filtration, ensuring reliable performance under tough, high-temperature conditions without compromising air permeability. This membrane offers promising potential for industrial applications. Further optimizations and applications can be explored.

• Korean Journal of Materials Research
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• v.10 no.1
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• pp.77-82
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• 2000

A surface of polytetrafluoroethylene(PTFE) was modified with changing ion doses by 1 keV $Ar^+$ ion irradiation and Cu films having thickness $5000\;{\AA}$ were deposited on the modified PTFE. The SEM study showed that the surface texture of modified PTFE was in the form of cones whose height increased depending on ion doses. Through XPS spectra, it was found that the intensity of F ls peaks decreased with ion doses by preferential sputtering of F atoms and the C-C and / or C-F chains were formed by the crosslinking in the newly unstable chains. Cu films were deposited uniformly along the filaments formed on the modified PTFE. In x-ray diffraction (XRD) spectra of deposited Cu films on modified PTFE, a preferred orientation along (111) and (200) planes was found and the peak intensity of (111) plane increased as surface roughness of modified PTFE increased. The resistivity of Cu films was changed from $2.7{\mu}{\Omega}cm$ of unmodified PTFE to $4.3{\mu}{\Omega}cm$ of modified PTFE at ion dose of $1{\times}10^{16}/\textrm{cm}^2$ and the abrupt increase of resistivity in the modified PTFE at ion dose of $1{\times}10^{17}/\textrm{cm}^2$ was due to being cut off the film which resulted from the increased surface roughness.