• Polymer(Korea)
• /
• v.38 no.2
• /
• pp.257-264
• /
• 2014

In this study, we modified silica nanoparticles with bis[3-(trimethoxysilyl)propyl]ethylenediamine (BTPED) silane coupling agent, which has two secondary amino groups in a molecule, to introduce amino groups on the silica surface. After modification of silica, we used acrylate group containing 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHM) to introduce polymerizable methacrylate groups by Michael addition reaction. We used Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA) and liquid and solid state cross polarization magic angle spinning (CP/MAS) nuclear magnetic resonance spectroscopy (NMR) to understand the reactions between N-H groups of BTPED modified silica surface and acrylate groups of AHM monomer. We confirmed Michael addition reaction between BTPED modified silica and AHM completed in 2 hr reaction time. We also found increased methacrylate group introduction with increase of mol ratio of the acrylate group of AHM to N-H group of BTPED modified silica by increase of C=O peak area of measured FTIR spectra. These results were also supported by EA and solid state $^{13}C$ and $^{29}Si$ NMR results.

• Applied Chemistry for Engineering
• /
• v.27 no.5
• /
• pp.472-477
• /
• 2016

We studied the effects of anodic oxidation treatments of carbon fibers on interfacial adhesion of the carbon fibers-reinforced epoxy matrix composites with various current densities. The surface of treated carbon fibers was characterized by atomic force microscope (AFM), field emission-scanning electron microscope (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The interlaminar shear strength (ILSS) of the composites was determined by a short beam shear test. This result showed that both the roughness and oxygen group of the carbon fibers surface increased in proportion to the current density. After anodic-oxidation-treated, the ILSS also increased as a function of the current density. In addition, the proportional relationship between ILSS and phenolic hydroxyl group was confirmed. The ILSS of the CF-2.0 sample increased by 4% compared to that of the CF-AS sample, because the anodic oxidation treatment increased the oxygen group and roughness on the carbon fibers surface, which leading to the improvement of the interfacial adhesion of the carbon fibers-reinforced epoxy matrix composites. Among these, the phenolic hydroxyl group which has the proportional relationship with ILSS is found to be the most important factor for improving the interfacial adhesion of the carbon fibers-reinforced epoxy matrix composites.

• Polymer(Korea)
• /
• v.36 no.5
• /
• pp.668-676
• /
• 2012

In this study, we modified silica nanoparticles with bis[3-(trimethoxysilyl)propyl]amine (BTMA) silane coupling agent to introduce secondary amino groups on the silica surface. After modification of silica, we investigated effects of different types of (meth)acrylate group containing monomers on the Michael addition reaction to introduce reactive (meth)acrylate groups on the BTMA modified silica surface. We used two kinds of (meth)acrylate monomers, trimethylolpropane ethoxylate triacrylate (TMPET) which has three identical acrylate groups, and 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHM) which has one acrylate and one methacrylate group. We used fourier transform infrared spectroscopy (FTIR), elemental analysis (EA) and solid state cross-polarization magic angle spinning (CP/MAS) nuclear magnetic resonance spectroscopy (NMR) to understand reactions between NH groups on the silica surface with (meth)acrylate groups of TMPET and AHM monomers. We found almost complete Michael addition reaction between all three acrylate groups of TMPET with NH groups on the BTMA modified silica. But, for the AHM treatment of BTMA modified silica, we found Michael addition reaction occurred only between acrylate groups of AHM and NH groups of silica surface, not between methacrylate groups of AHM and NH groups of BTMA modified silica surface.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.7
• /
• pp.33-39
• /
• 2015

In this work, SU-8 passivated IZO thin-film transistors(TFTs) made by solution-processes was investigated for enhancing stability of indium zinc oxide(IZO) TFT. A very viscous negative photoresist SU-8, which has high mechanical and chemical stability, was deposited by spin coating and patterned on top of TFT by photo lithography. To investigate the enhanced electrical performances by using SU-8 passivation layer, the TFT devices were analyzed by X-ray phtoelectron spectroscopy(XPS) and Fourier transform infrared spectroscopy(FTIR). The TFTs with SU-8 passivation layer show good electrical characterestics, such as ${\mu}_{FE}=6.43cm^2/V{\cdot}s$, $V_{th}=7.1V$, $I_{on/off}=10^6$, SS=0.88V/dec, and especially 3.6V of ${\Delta}V_{th}$ under positive bias stress (PBS) for 3600s. On the other hand, without SU-8 passivation, ${\Delta}V_{th}$ was 7.7V. XPS and FTIR analyses results showed that SU-8 passivation layer prevents the oxygen desorption/adsorption processes significantly, and this feature makes the effectiveness of SU-8 passivation layer for PBS.

• Polymer(Korea)
• /
• v.33 no.2
• /
• pp.169-174
• /
• 2009

Silicone hydrogels incorporated with poly(ethylene glycol)(PEG) were prepared and characterized to evaluate the effects of PEG on contact lenses. The silicone hydrogels were copolymerized with methacryloxypropyl tris(trimethylsiloxy) silane (TRIS), methyl methacrylate (MMA), N,N-dimethyl acrylamide (DMA) and PEG-containing monomers such as poly(ethylene glycol) methyl ether methacrylate (PEG- MEM). The silicone hydrogels were characterized using Fourier transform infrared spectroscopy (FT-IR), electron spectroscopy of chemical analysis (ESCA), and scanning electron microscopy (SEM). Water absorbance, water contact angle and light transmittance of the silicone hydrogels were evaluated. The experiments of protein adsorption were also carried out to evaluate the protein adsorption in tears. The peak intensity of C-O bond was increased by the incorporation of PEG-containing monomers and thus PEG incorporation into silicone hydrogels could be confirmed. Phase separation was not shown by the SEM observation of the cross-section of silicone hydrogels. Water absorbancy was increased, while water contact angle and light transmittance were decreased with increasing incorporation of the PEG-containing monomers. The absorption of proteins in tears, albumin, lysozyme and $\gamma$-globulin, on the surface of silicone hydrogels was decreased with increasing incorporation of the PEG-containing monomers.

• Korean Chemical Engineering Research
• /
• v.62 no.3
• /
• pp.246-252
• /
• 2024

In this study, impurities such as Li and F were removed from waste graphite through citric acid treatment, and changes in structural properties, capacity, and cycle stability of regenerated graphite were observed accordingly. Regenerated graphite pretreated in a nitrogen atmosphere was treated with citric acid, and its structure and characteristics were analyzed through SEM (Scanning Electron Microscope), FT-IR (Fourier Transform Infrared spectroscopy), XRD (X-ray Diffraction), and XPS (X-ray Photoelectron Spectroscopy). Waste graphite that was not treated with acid had a rapid decrease in capacity before 70 cycles, but graphite that had been treated with citric acid showed a capacity of 302.9 mAh g^-1 and a capacity retention rate of 93.1% at 100 cycles. In addition, despite changes in current density in rate performance, samples treated with citric acid showed 340.2 mAh g^-1 performance at 1.0C without change in capacity. As a result, it was confirmed that citric acid treatment not only effectively removed impurities and showed a high capacity retention rate, but also showed stability even at high current densities.

• Journal of the Optical Society of Korea
• /
• v.7 no.4
• /
• pp.240-244
• /
• 2003

Simultaneous determination of concentrations for four major components in human blood serum was investigated using a Fourier-transform mid-infrared spectroscopy. Infrared spectra of human blood serum were measured in 8.404 ∼ 10.25 ${\mu}m$ range where the highest absorption peaks of glucose are located. A partial least square (PLS) algorithm was utilized to establish a calibration model for determining total protein, albumin, globulin and glucose levels which are commonly measured metabolites. The standard error of cross validation obtained from our multivariate calibration model was 0.24 g/dL for total protein, 0.15 g/dL for albumin, 0.17 g/dL for globulin, and 6.68 mg/dL for glucose, which are comparable with or meet the criteria for clinical use. The results indicate that the infrared absorption spectroscopy can be used to predict the concentrations of clinically important metabolites without going through a chemical process with a reagent.

• Advances in environmental research
• /
• v.9 no.3
• /
• pp.215-232
• /
• 2020

Crude oils are essential source of energy. It is majorly found in geographical locations beneath the earth's surface and crude oil is the main factor for the economic developments in the world. Natural crude oil contains unrefined petroleum composed of hydrocarbons of various molecular weights and it contains other organic materials like aromatic compounds, sulphur compounds, and many other organic compounds. These hydrocarbons are rapidly getting degraded by biosurfactant producing microorganisms. The present study deals with the isolation, purification, and characterization of biosurfactant producing microorganism from oil-contaminated soil. The ability of the microorganism producing biosurfactant was investigated by well diffusion method, drop collapse test, emulsification test, oil displacement activity, and blue agar plate method. The isolate obtained from the oil contaminated soil was identified as Bacillus subtilis. The identification was done by microscopic examinations and further characterization was done by Biochemical tests and 16SrRNA gene sequencing. Purification of the biosurfactant was performed by simple liquid-liquid extraction, and characterization of extracted biosurfactants was done using Fourier transform infrared spectroscopy (FTIR). The degradation of crude oil upon treatment with the partially purified biosurfactant was analyzed by FTIR spectroscopy and Gas-chromatography mass spectroscopy (GC-MS).

• Journal of Electrochemical Science and Technology
• /
• v.8 no.4
• /
• pp.274-281
• /
• 2017

This paper describes the simple fabrication of an electrode modified with electrochemically reduced graphene oxide (ERGO) for the simultaneous electrocatalytic detection of dopamine (DA), ascorbic acid (AA), and uric acid (UA). ERGO was formed on a glassy carbon (GC) electrode by the reduction of graphene oxide (GO) using linear sweep voltammetry. The ERGO/GC electrode was formed by subjecting a GO solution ($1mg\;mL^{-1}$ in 0.25 M NaCl) to a linear scan from 0 V to -1.4 V at a scan rate of $20mVs^{-1}$. The ERGO/GC electrode was characterized by Raman spectroscopy, Fourier transform infrared spectroscopy, contact angle measurements, electrochemical impedance spectroscopy, and cyclic voltammetry. The electrochemical performance of the ERGO/GC electrode with respect to the detection of DA, AA, and UA in 0.1 M PBS (pH 7.4) was investigated by differential pulse voltammetry (DPV) and amperometry. The ERGO/GC electrode exhibited three well-separated voltammetric peaks and increased oxidation currents during the DPV measurements, thus allowing for the simultaneous and individual detection of DA, AA, and UA. The detection limits for DA, AA, and UA were found to be 0.46, 77, and $0.31{\mu}M$ respectively, using the amperometric i-t curve technique, with the S/N ratio being 3.

• Applied Science and Convergence Technology
• /
• v.24 no.4
• /
• pp.90-95
• /
• 2015

The adsorption behavior of tris (dimethylamino)-cyclopentadienyl-zirconium (Cp-Zr) precursor using an in-situ attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FT-IR) was studied. In attempt to improve the detection intensity of an adsorbed precursor, nanoparticles were uniformly distributed on the Ge ATR crystal surface employing the spray method. The absorption characteristics studies were carried out over the Ge crystal temperature in the range of $30{\sim}50^{\circ}C$. Upon increasing the temperature, a reduction of absorption was observed. Based on the peak intensities of ATR-FT-IR spectroscopy, higher-$ZrO_2$ absorption efficiency occurs when the nano-particles are utilized compared to pure Ge crystal.