• Korean Chemical Engineering Research
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• v.61 no.3
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• pp.439-445
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• 2023

In this study, silver nanoparticles were synthesized by reducing silver nitrate with PVA, and the solution prepared by adding carboxymethyl cellulose (CMC) to the silver nanoparticles was coated on a PET substrate to prepare a coating film with antibacterial and antifogging function. When the coating films were in contact with water vapor at 80 ℃, the uncoated PET substrate was blurred due to the scattering of light due to the occurrence of fog, while the coating film coated with silver nanosol with CMC remained transparent despite contact with water vapor, showing excellent antifogging function. In addition, the antibacterial properties of the coating films were measured by film adhesion method for Staphylococcus aureus, gram-positive bacteria, and Escherichia coli, gram-negative bacteria. The uncoated PET substrate showed a large number of colonies of Staphylococcus aureus and Escherichia coli, while the coating film coated with the silver nanosol greatly inhibited the growth of Staphylococcus aureus and Escherichia coli, resulting in excellent antibacterial effect.

• Polymer(Korea)
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• v.30 no.4
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• pp.298-304
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• 2006

Blends of poly (acrylic acid-co-maleic acid)(PAM) with poly (vinyl alcohol)(PVA) were obtained by solution blending. The blends were solvent-on to a film to examine thermo-mechanical properties and gas permeability. The transition temperatures $(T_g\;and\;T_m)$ of the blends remained constant regardless of PAM contents. However, the values of enthalpy changes corresponding to melting transition $({\Delta}H_m)$ and initial degradation temperature $({T_D}^i)$ were decreased with increasing PAM content. The values of ultimate strength and initial modulus gave the maximum value at the 12 wt% PAM then decreased with further increase of PAM content up to 15 wt%. To measure the gas permeability of the PVA/PAM blend films, the PVA blend solutions were coated onto both biaxially oriented propylene (BOPP) and poly (ethylene terephthalate)(PET) films. The oxygen transmission rate $(O_2\;TR)$ permeability values mono- tonically decreased with increasing PAM content. However, moisture vapor transmission rate was not affected by PAM content.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.9
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• pp.636-642
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• 2013

In order to overcome drawbacks (i.e., filtration and recovery) of conventional powder type photocatalysts, nano-ZnO/Laponite/PVA (ZLP) photocatalyzed adsorption balls were developed by using in situ mixing of nanoscale ZnO as a photocatalyst, and Laponite as both adsorbent and supporting media in deionized water, followed by the poly vinyl alcohol polymerization with boric acid. The optimum mixing ratio of nano-ZnO:Laponite:PVA:deionized water was found to be 3:1:1:16 (by weight), and the mesh and film produced by PVA polymerization with boric acid might inhibit both swelling of Laponite and detachment of nanoscale ZnO from ZLP balls. Drying ZLP balls with microwave (600 watt) was found to produce ZLP balls with stable structure in water, and various sizes (55~500 ${\mu}m$) of pore were found to be distributed based on SEM and TEM results. In the initial period of reaction (i. e., 40 min), adsorption through ionic interaction between methylene blue and Laponite was the main removal mechanism. After the saturation of methylene blue to available adsorption sites for Laponite, the photocatalytic degradation of methylene blue occurred. The effective removal of methylene blue was attributed to adsorption and photocatalytic degradation. Based on the results from this study, synthesized ZLP photocatalyzed adsorption balls were expected to remove recalcitrant organic compounds effectively through both adsorption and photocatalytic degradation, and the risks of environmental receptors caused by detachment of nanoscale photocatalysts can be reduced.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.449-455
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• 2011

This study was performed to develop antimicrobial films using polyvinyl alcohol and methyl cellulose. Methyl cellulose and polyvinyl alcohol films plasticized with PEG(polyethylene glycol) were prepared by solvent casting process under addition of 0.025~1.0 wt% ampicillin and 0.1~1.0 wt% streptomycin as an antimicrobial agent. The mechanical properties of prepared films were examined by universal testing machine(UTM). Tensile strength of methyl cellulose films was 15.44~21.70 $N/mm^2$. Tensile strength of PVA(15 wt%) film was 20.2~51.5 $N/mm^2$, and the tensile strength of the antimicrobial films were decreased linearly with increasing the antibiotic loading amount up to 1 wt%. Antimicrobial activities of PVA and methyl cellulose films containing ampicillin and streptomycin through the disc diffusion test for the Staphylococcus aureus and Escherichia coli. The antimicrobial activity of methyl cellulose films and PVA containing ampicillin were higher than that of containing streptomycin methyl cellulose films. The results indicate the films may be a proper materials for antimicrobial packing applications.

• Resources Recycling
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• v.21 no.2
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• pp.53-58
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• 2012

A laboratory study was carried out to recover KI crystals with high purity from a waste solution generated from the production of polarizing film for LCD industry. The waste solution contains 1 to 4% KI, and other impurities such as B, PVA and etc. More than 95% purity of KI crystals were produced through refining process such as vacuum evaporation and fractional crystallization. Most of B compounds and impurities were removed by concentrating the waste solution until KI content reached about 50%. The KI crystals were washed with solvents to remove most of PVA which gave result in producing 99.5% purity of crystals. The overall recovery of KI was about 90% during the concentration process.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1291-1293
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• 2005

Hybrid insulator pentacene thin film transistors (TFTs) were fabricated with thermally grown oxide and cross-linked polyvinylalcohol (PVA) including surface treatment by dilute ploymethylmethacrylate (PMMA) layers on $n^+$ doped silicon wafer. Through the optimization of $SiO_2$ layer thickness in hybrid insulator structure, carrier mobility was increased to above 35 times than that of the TFT only with the gate insulator of $SiO_2$ at the same transverse electric field. The carrier mobility of 1.80 $cm^2$/V-s, subthreshold swing of 1.81 V/decade, and $I_{on}$/ $I_{off}$ current ratio > 1.10 × $10^5$ were obtained at low bias (less than -30 V) condition. The result is one of the best reported performances of pentacne TFTs with hybrid insulator including cross-linked PVA material at low voltage operation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.235-238
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• 2004

본 연구는 반도체소자 제조공정에 적용되는 CMP공정 중 LPP(Landing Plug Poly) Contact간의 소자 분리를 위해 진행되는 LPP CMP의 후 세정 과정에서 유발되는 방사형 Defect 제거에 관한 내용이다. 방사형 Defect은 LPP CMP 후에 노출되는 BPSG, Poly, Nitride Film과 연마재로 사용되는SiO2 입자, 후 세정과정에서 적용되는 SC-1, DHF, $NH_4OH$ Chemical과 Brush와의 상호작용에 의해 발생되며, Cleaning시의 산성 분위기 하에서 각 물질간의 pH와 Zeta Potential의 차이에서 기인한다. 이 Defect을 제거하기 위해 LPP CMP후에 Film 표면에 노출되는 각 물질의 표면 특성과 CMP 후 오염입자의 흡착과 재 흡착에 영향을 미치는 Electrostatic force와 Van der Waals force, PVA Brush에 의한 Mechanical force의 상호작용을 고려하여 최적 후 세정 조건을 제시 하였다.

• Korean Chemical Engineering Research
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• v.59 no.3
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• pp.443-449
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• 2021

A biodegradable shatterproof thin film material having excellent water resistance and applicability was prepared by crosslinking through esterification of starch and citric acid. In order to improve the thin film formation and physical properties of these materials, PVA and glycerin were added to secure the flexibility of the applied thin film. In addition, conditions for optimizing material functionality such as swelling degree and solubility in water according to reaction time, temperature, and concentrations of raw materials and additives were analyzed. The crosslinking reaction of starch and citric acid was confirmed by FT-IR analysis, and it was found that single and multiple esterification reactions occurred simultaneously in these reaction processes. It can be seen that the crosslinked starch-citric acid thin film material was decomposed about 95% after 12 weeks after landfilling, and thus biodegradability was excellent.

• Journal of the Korean Chemical Society
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• v.36 no.4
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• pp.496-503
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• 1992

An ISFET urea sensor was fabricated by immobilizing the urease using photosensitive polymer, poly(vinyl alcohol)-SbQ on the H$^+$ sensing $Si_3$$N_4$ thin film of pH-ISFET. The sensor could determine the urea concentration in the range of 1∼50 mg/dl with fast response and good repeatability. For its application to clinical analysis, the interferences of the various materials which cause inhibition in urease catalytic reactions in blood was investigated. The results of the urea measurements in blood plasma using the ISFET urea sensor were compared with these of conventional spectrophotometric method.

• Journal of the Korean Applied Science and Technology
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• v.16 no.4
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• pp.317-322
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• 1999

Transparent films were prepared using the sol-gel process by mixing TEOS with PVA solution that was solved in EtOH and distilled water homogeneously. HCl, $CH_3COOH$ and $NH_4OH$ were used as catalysts of the sol-gel process, and for improving the flexibility of films glycerol was used as plasticizer. In case of each catalyst, transparency and tensile strength were increased, and glass transition temperature (Tg) was shifted to higher temperature with increasing TEOS ratio. Also, in case of adding the plasticizer, the flexibility of films was increased. On the contrary, transparency, thermal stability and tensile strength were decreased with increasing HCl and $NH_4OH$ ratio. Also, the range of being made of film type was expanded when $CH_3COOH$ was used than HCl and $NH_4OH$.