• Journal of Pharmaceutical Investigation
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• v.31 no.3
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• pp.173-180
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• 2001

The physicochemical characteristics such as glass transition temperature (Tg), surface energy, swelling and FT-IR of [P(AA-co-PEGMM)], a copolymer of acrylic acid (AA) and polyethyleneglycol monoethylether mono methacrylate (PEGMM), were evaluated. The Tg of [P(AA-co-PEGMM)] decreased with increasing PEGMM content. [P(AA-co-PEGMM)] with 18 mole% PEGMM had the Tg of about $40^{\circ}C$, the similar physiological temperature of human. Moreover, [P(AA-co-PEGMM)] with lower PEGMM content had higher hydration and expected lower mucoadhesive strengths. To predict the mucoadhesiveness of [P(AA-co-PEGMM)] films, the contact angle of films were measured. With the increasing content of PEGMM of films, the contact angle was increased and the higher mucoadhesive forces was expected. ATR-FTIR studies revealed that the addition of the PEG moiety in AA increased the potential of hydrogen bonding for [P(AA-co-PEGMM)] as compared to cross linking polyacrylic acid (cr-PAA) because the oxygen in the repeat unit of PEG contributed in the formation of hydrogen bonding in the presence of mucin solution.

• Membrane and Water Treatment
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• v.4 no.2
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• pp.109-126
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• 2013

Surface modification by low-pressure ammonia ($NH_3$) plasma on commercial thin-film composite (TFC) membranes was investigated in this study. Surface hydrophilicity, total surface free energy, ion exchange capacity (IEC) and zeta (${\zeta}$)-potentials were determined for the TFC membranes. Qualitative and quantitative analyses of the membrane surface chemistry were conducted by attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectroscopy. Results showed that the $NH_3$ plasma treatment increased the surface hydrophilicity, in particular at a plasma treatment time longer than 5 min at 50 W of plasma power. Total surface free energy was influenced by the basic polar components introduced by the $NH_3$ plasma, and isoelectric point (IEP) was shifted to higher pH region after the modification. A ten (10) min $NH_3$ plasma treatment at 90 W was found to be adequate for the TFC membrane modification, resulting in a membrane with better characteristics than the TFC membranes without the modification for water treatment. The thin-film chemistry (i.e., fully-aromatic and semi-aromatic nature in the interfacial polymerization) influenced the initial stage of plasma modification.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.456-459
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• 2003

Polychloroprene(CR) is well known as elastomer commonly utilized in the electrical. It is mainly used for cable jacket and insulator. The irradiation degradation property of polymer materials is very important to prevent unexpected accidents in the Nuclear Power Plant(NPP). The irradiation degradation is caused by the oxidation of polymer materials, and this oxidation is occurred by oxygen radical produced from air. In this study, we evaluate the oxidation properties of CR. CR is irradiated for 200, 400, 600, 1000 kGy radiation dose. The oxidation properties of irradiated CR are investigated by differential scanning calorimetry, dynamic mechanical properties and FT-IR/ATR. Glass transition temperature(Tg), decomposition onset temperature(DOT), loss modulus and mechanical tan $\delta$ values are compared together. The irradiation limit of CR in the NPP, is known for 500 kGy, and this is exactly matched with investigated results.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.6
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• pp.66-72
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• 2015

This study was conducted to investigate the effects of optical brightening agents (OBA) on the chemical degradation characteristics of paper cellulose during humid heating aging. Three different types of OBAs were applied to a filter paper by dipping it in OBA solutions whose concentrations were controlled to 1% and 2%. The filter papers with an OBA were artificially aged at $80^{\circ}C$ and 65% RH, and the changes in pH of paper and viscosity of cellulose were evaluated. Their functional groups were also analyzed by ATR-FTIR (at-tenuated total reflectance fourier transform infrared spectroscopy). It was found that OBAs influenced the chemical degradation of paper cellulose during humid heating aging. Higher concentration of OBA solutions accelerated the degradation of paper cellulose. Especially, after aging for 12 days, the paper cellulose treated with the tetra-type OBA were the most significantly aged among the three types of OBAs. It was assumed that pH of OBA solutions affected the aging characteristics.

• Korean Membrane Journal
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• v.6 no.1
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• pp.55-60
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• 2004

In recent years, an increasing interest in membrane technology has been observed in chemical and environmental industry. Membrane technology has advantages of low cost, energy saving and environmental clean technology comparing to conventional separation processes. Pervaporation is one of new advanced membrane technology applied for separation of azeotropic mixtures, aqueous organic mixtures, organic solvent and petrochemical mixtures. Sodium alginate composite membranes were prepared for the enhancement of long-term stability of pervaporation performance of water-ethanol mixture using pervaporation. Sodium alginate membranes were crosslinked with CaCl$_2$ and coated with polyelectrolyte chitosan to protect washing out of calcium ions from the polymer. The surface structures of PAN and hydrolysed PAN membrane were confirmed by ATR Fourier transform infrared (FT-IR). A field emission scanning electron microscopy (FE-SEM; Jeol 6340F) operated at 15 kV. Concentration profiles for Ca in the membrane surface and membrane cross-section were taken by an energy dispersive X-ray (EDX) analyser (Jeol) attached to the field emission scanning electron microscopy (Jeol 6340F). Pervaporation experiments were done with several operation run times to investigate long-term stability of the membranes.

• Bulletin of the Korean Chemical Society
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• v.29 no.7
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• pp.1349-1352
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• 2008

We report a novel patterning method for a homo-polymeric poly(3-hexylthiophene) (P3HT) nanofilm particularly capable of strong adhesion to a $SiO_2$ surface. An oxidized silicon wafer substrate was micro-contact printed with n-octadecyltrichlorosilane (OTS) monolayer, and subsequently its negative pattern was selfassembled with three different amino-functionalized alkylsilanes, (3-aminopropyl)trimethoxysilane (APS), N- (2-aminoethyl)-3-aminopropyltrimethoxy silane (EDAS), and (3-trimethoxysilylpropyl) diethylenetriamine (DETAS). Then, P3HT nanofilms were selectively grown on the aminosilane pre-patterned areas via the vapor phase polymerization method. To evaluate the adhesion, patterning, and the film itself, the PEDOT nanofilms and SAMs were investigated with a $Scotch^{(R)}$ tape test, contact angle analyzer, ATR-FT-IR, and optical and atomic force microscopes. The evaluation showed that the newly developed all bottom-up process can offer a simple and inexpensive patterning method for P3HT nanofilms robustly adhered to an oxidized Si wafer surface by the mediation of $FeCl_3$ and amino-functionalized alkylsilane SAMs.

• Journal of Radiation Industry
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• v.6 no.4
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• pp.317-322
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• 2012

In this study, the preparation of a temperature-responsive poly(N-isopropylacrylamide) (PNIPAAm)-grafted surface was performed using an eco-friendly and biocompatible ion beam-induced surface graft polymerization. The surface of a perfluoroalkoxy (PFA) film was activated by ion implantation and N-isopropylacrylamide (NIPAAm) was then graft polymerized selectively onto the activated regions of the PFA surfaces. Based on the results of the peroxide concentration and grafting degree measurements, the amount of the peroxide groups formed on the implanted surface was dependant on the fluence, which affected the grafting degree. The results of the FT-IR-ATR, XPS, and SEM confirmed that the NIPAAm was successfully grafted onto the implanted PFA. Moreover, the contact angle measurement at different temperatures revealed that the surface of the PNIPAAm-grafted PFA film was temperature-responsive.

• Journal of the Korean Applied Science and Technology
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• v.29 no.1
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• pp.95-101
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• 2012

To manufacture of a completely biodegradable and compostable biomass -based blend polymer film, two types of cellulose acetates(DS=2.4 and DS=2.7) were blended with 5 - 50 wt% of low average molecular weight polylactide(PLA) by mixing each polymer solution having same viscosity in 10 wt% methanol/dichloromethane. Their surface morphology, thermal and mechanical properties were studied. The chemical structures of blend films were confirmed by the fourier transform IR spectroscopy with attenuated total reflection(FT-IR ATR) spectrophotometer. Scanning electron microscope(SEM) photos of blend films of both CAs with less than 5 % of PLA showed homogeneous morphology. On the contrary, the other blends with higher than 20 wt% of PLA content showed a large phase separation with spherical domains. The thermal property of blend films was also analyzed with thermogravimetric analysis(TGA) and differential scanning calorimeter(DSC). The tensile strength of CA/PLA blend films was increased up to $820kg_f/cm^2$ for TAC/PLA and $600kg_f/cm^2$ for DAC/PLA.

• Analytical Science and Technology
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• v.22 no.6
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• pp.464-470
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• 2009

For the investigation of the oxidation behavior for titanium metal at various temperatures, titanium specimens were heated for 2 hours in the range of $300{\sim}1000^{\circ}C$, individually. And then X-ray diffraction(XRD), scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS) and attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopic analyses were carried out. At $300^{\circ}C$, infrared absorption bands on the surface of the titanium specimen were shown in a spectrum by the oxygen uptake of titanium metal(hexagonal). At increased temperature, not only infrared absorption bands but also X-ray diffraction peaks for the titanium oxide were grown and shifted to low wave number ($cm^{-1}$) and angle($^{\circ}$) due to the more oxygen diffusion into titanium metal. At $700^{\circ}C$, $Ti_3O$ (hexagonal phase) was identified by X-ray diffractometer. $TiO_2$ (rutile, tetragonal phase) layer was produced on the surface of the specimen below $1{\mu}m$ in thickness at $600^{\circ}C$, and grown about $2{\mu}m$ at $700^{\circ}C$ and with $110{\mu}m$ in thickness at $1000^{\circ}C$. Above $900^{\circ}C$, (110) plane of the crystal on the surface of rutile-$TiO_2$ layer was grown.

• Journal of the Korean Applied Science and Technology
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• v.33 no.2
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• pp.247-254
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• 2016

Since microzirconia has excellent thermal and mechanical properties with high chemical and electrical resistance, it can be used in various fields. When the surface of zirconia becomes hydrophilic, its dispersibility in water will be improved as well as the resistance to most hydrophobic contaminants will be increased. In this study, we investigated the introduction of a hydrophilic groups on the microzircornia surface through hydrolysis and condensation reactions with two different silanes containing hydrophilic functional groups, such as ${\gamma}$-aminopropyltrimethoxysilane (APS) and ${\gamma}$-ureidopropyltrimethoxysilane (UPS) at different pH and concentration conditions. A covalent bond formation between the surface hydroxyl groups of zirconia and that of hydrolyzed silanes was confirmed by ninhydrin test and FT-IR spectroscopy. However, the presence of Si on the surfaces of both silane modified microzirconias was unable to detect by SEM/EDS technique. In addition, particle size analysis results provide that the size of microzirconia was changed to smaller or bigger than that of original zirconia due to crushing and aggregation during the modification process. The water dispersibility was improved for only APS modifed zirconia (AS-2 and AS-3) under neutral pH condition, but the water dispersibility and stability for all cases of 0.5~2% UPS modifed zirconia (US series) were much improved.