• 한국미생물·생명공학회지
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• 제24권5호
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• pp.546-552
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• 1996

The applicability of chitosan, a biodegradable natural polymer, as the coating material to prevent the dispersal of the spores of the apple white rot agent Botryosphaeria dothidea, was investigated. The physical properties of mixed chitosan/polyvinyl alcohol(PVA) film showed the increased physical properties for film formation, such as tensil strength, elongation, and viscosity, compared to either chitosan or PVA film. The FT-IR spectra of chitosan/PVA film indicated that the film was formed by simple blending not by any new synthetic bond. The chitosan and chitosan/PVA film showed effective antifungal activity on B. dothidea. The formed films were well decomposed by ASTM strains used for biodegradability test, on the other hand, the PVA film could not be decomposed by above standard strains. The field test at apple orchard showed that the dispersal of B. dothidea spores could be effectively reduced by coated film, especially by chitosan/PVA film. The spore dispersal was reduced upto 97.0% by 1.0% chitosan/5.0% PVA film during 4 months.

• 한국염색가공학회지
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• 제16권4호
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• pp.19-25
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• 2004

Both poly(vinyl alcohol)$(PVA)-I_2$ and PVA-dye polarizing film were prepared using PVA with number-average degree of polymerization of 1,700, 2,300, 2,600. The optical property of used dye in this study closed to the that of iodine. The PVA-dye polarizing film was prepared through the dyeing process. In comparison of the result of the measurement of the heat and humidity resistance of two types polarizing films, it of PVA-dye polarizing film was higher than that of a conventional $PVA-I_2$polarizing film. The transmittance and the polarization efficiency of PVA-dye polarizing film was significantly influenced by dye concentration, dipping time, salt concentration, and temperature of dye bath. The PVA-dye polarizing film exhibited a high polarization efficiency of 99.3% and a good transmittance of 42.4%.

• 공업화학
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• 제10권4호
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• pp.603-607
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• 1999

Potassium iodide(KI)를 함유하는 poly(vinyl alcohol)(PVA) 필름의 산화공정에 의해 제조된 PVA-iodine 착제물(PVA_KI계)의 편광특성을 조사하였다. PVA-KI계 편광필름의 UV-visible 스펙트럼은 220 nm, 290~360 nm와 650 nm에서 $I^{-}$, $I{_3}{^-}$와 $I{_5}{^-}$ 발색단에 해당하는 흡수밴드를 각각 나타냈다. PVA-KI계 필름의 편광효율과 투과도는 산화시간, 연신비율, KI 농도 등에 크게 의존하였다. 제조된 편광필름은 99.5%와 45%의 높은 편광효율 및 투과도를 나타냈다. 특히 산화공정에 의해 제조된 편광필름의 열저항은 기존의 PVA-$I_2$계 편광필름에 비하여 뛰어났다. 이러한 결과는 PVA 편광필름의 산화공정의 차이에 기인된다고 생각된다.

• 폴리머
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• 제24권5호
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• pp.713-720
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• 2000

수평균 중합도 900 및 교대배열기 함량 63.1%의 교대배열 poly(vinyl alcohol) (s-PVA)을 사용하여 s-PVA/요오드계 편광필름을 제조하였다. 흔성배열 PVA/요오드계 필름과 비교할 때 편광도는 자연신비에서도 99% 이상의 값을 가짐으로써 향상된 결과를 보였으나 투과도는 약간 저하되는 경향을 보였다. 따라서 침지액의 요오드 농도를 보다 낮추고 4배의 연신비를 유지함으로써 우수한 투과도와 편광도를 가지는 필름을 제조할 수 있었다. 한편, s-PVA/요오드 필름의 열수하에서의 탈착은 현저히 억제되었다. 결정화도, (100)면의 결정크기 및 면간거리가 조금씩 감소하거나 더 이상 증가하지 않는 것으로부터 침지시간 초기에는 요오드가 주로 결정영역에서 복합체를 형성하고, 이후에는 주로 결정면 밖에서 복합체를 형성하거나 단순한 물리적인 흡착을 이루고 있음을 확인하였다.

• 한국전기전자재료학회논문지
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• 제23권3호
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• pp.177-182
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• 2010

The pentacene-based organic thin film transistors(OTFTs) using polyvinylalcohol(PVA) alignment layer were fabricated on the $SiO_2$ evaporated to n-type (111) Si substrates. The pentacene film was deposited by thermally evaporated at $10^{-7}$ torr. X-ray diffraction (XRD) and atomic force microscope(AFM) measurement showed pentacene film which deposited on rubbed PVA layers were partially crystallized at (001) plane. The pentacene OTFTs with PVA layers rubbed perpendicular to the direction of current flow was shown to align better orientation than parallel rubbed case and thus to enhance the mobility and saturation current by a factor of 2.3 respectively. We obtained mobility by 0.026 $cm^2$/Vs and on-off current ratio by ${\sim}10^8$.

• 반도체디스플레이기술학회지
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• 제9권4호
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• pp.1-5
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• 2010

The PVA (poly-vinyl alcohol) insulators were spun coated onto ITO coated glass substrates with the capacitors of Glass/ITO/PVA/Al structure. The effects of PVA concentrations (3.0, 4.0 and 5.0 wt%) on the morphology and electrical properties of the films were investigated. As the concentration of PVA increased from 3.0 to 5.0 wt%, the leakage current of device decreased from 17.1 to 0.23 pA. From the AFM measurement, the RMS value decreased with increasing PVA concentration, showing the improvement of insulator film roughness. The capacitances of the films with PVA concentrations of 4.0 and 5.0 wt% were about 28.1 and 24.2 nF, respectively. The lowest leakage current of 1.77 PA was obtained at the film thickness of 117.5 nm for the device with fixed PVA concentration of 5.0 wt%.

• 한국기계가공학회지
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• 제20권11호
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• pp.1-8
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• 2021

In this study, the water resistance and mechanical properties of heat-treated polyvinyl alcohol (PVA)/cellulose nanocrystal (CNC) films were investigated. PVA is the most commonly used synthetic biodegradable polymers owing to its excellent properties. However, the water/moisture sensitivity and relatively poor mechanical properties of PVA limits its applications. Although heat treatment is a conventionally used method to improve the mechanical strength and water resistance of PVA, the effectiveness of this method is insufficient. Therefore, CNC was used to further improve the mechanical properties and water resistance of the heat-treated PVA film. PVA/CNC nanocomposites containing CNC contents of 0, 1, 3, 5, and 10 wt% were fabricated using solvent casting and subsequent heat treatment. The mechanical properties and water resistance of PVA/CNC films were significantly improved. The tensile strength and wet strength of the PVA/CNC film with a CNC content of 5 wt% (PVA/CNC 5%) were 184.5% and 136.0% higher than those of the untreated PVA, respectively. In addition, the water absorption and solubility of PVA/CNC 5% were 56.6% and 68.2% lower than those of the untreated PVA.

• 접착 및 계면
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• 제13권3호
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• pp.131-136
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• 2012

본 연구에서는 LCD 편광필름 제조용으로 시판되고 있는 poly(vinyl alcohol) (PVA) 필름을 반응성 이색성 염료로 염착시키고 500%로 일축 연신시킨 후 그 편광효율 및 투과도를 측정하였다. 이때 3,5-dichloro-2,4,6-triazine 잔기를 갖는 반응성 이색성 염료를 합성한 후 강염기성 수용액이 아닌 중성 유기 용매를 사용하여 염착을 수행하였다. 먼저, 시판되고 있는 편광필름용 PVA 필름의 검화도를 조사하였다. 이를 위해 시약급 PVA 분말시료의 검화도를 NMR 분광분석법을 사용하여 검정한 후, 필름을 제막하여 FT-IR 분광분석법으로 C-H기와 C=O기의 신축진동에 대한 흡광도 비를 측정하여 NMR 분광분석법으로 결정된 검화도와 상관시켜 봄으로써 상용화된 PVA 필름의 검화도를 in situ로 가늠할 수 있었다. 다음으로, NMR 분광분석법으로 검화도가 약 100%로 결정된 시판 PVA 필름을 두 가지 반응성 이색성 염료를 사용하여 염착하였다. 결과로서, 반응성 콩고레드를 염착시켜 제조한 PVA 편광필름과 반응성 다이렉트블랙 22를 염착시켜 제조한 PVA 편광필름의 광학특성을 비교할 때, 전자의 경우 편광효율이 우수하며, 후자의 경우 투과도가 우수함을 알 수 있었다.

• 폴리머
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• 제25권1호
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• pp.115-121
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• 2001

수평균 중합도 10000 및 신디오탁틱 다이애드기 함량 61.5%의 고분자량 신디오탁틱 폴리비닐알코올(high molecular weight syndiotactic poly(vinyl alcohol) (HMW s-PVA))/요오드계 편광필름을 제조하고 이의 흡착 거동 및 열수 하에서의 요오드의 내구성을 고찰하였다. 아탁틱 PVA 및 저분자량 s-PVA/요오드계 필름과 비교할 때 열수하에서의 HMW s-PVA 필름의 용해도 및 HMW s-PVA/요오드계 필름의 요오드 탈착은 현저히 억제되었다. 요오드 침지시간이 길어질수록 열수하에서의 요오드 탈착현상이 점차 심화되었다. 이는 처리 시간이 길어짐에 따라 PVA 분자와 요오드 분자간에 안정한 복합체가 형성되기보다는 물리적인 흡착에 의하여 흡착량이 증가하였기 때문이라고 설명된다.

• 한국염색가공학회지
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• 제33권3호
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• pp.147-152
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• 2021

Bulk polymerization was used to produce poly(vinyl acetate) with different molecular weights, which were then saponified to prepare poly(vinyl alcohol) (PVA) with different molecular weights. With P_n of 2,060 and 3,240, the optimum film formation concentrations of PVA were found 7.5wt.% and 6.5wt.%, respectively. The drawing characteristics of the PVA film prepared at the optimum film formation concentrations were experimented, as well as the thermal characteristics of the PVA film based on the drawing ratio were observed. When the drawing velocity was fixed, it was found that the drawing ratios of all samples decreased as the heat band gap increased, and the melting temperature of the PVA film slightly increased as the drawing ratio increased regardless of the P_n of PVA.