• Polymer(Korea)
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• v.35 no.1
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• pp.87-93
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• 2011

We developed a fluorene-containing multifunctional binder polymer for LCD color filter resist, and employing the binder polymer, carbon black based black photoresist (CBR) was prepared in order to apply it to the black matrix (BM). To obtain the multifunction of the binder polymer, we synthesized bisphenol fluorene epoxy acrylate-containing unsaturated polyester and identified the binder polymer structure with $^1H$ NMR, GPC and FTIR. The corresponding BFEA-polyester binder polymer was compared with the commercially available acryl binder toward the application to the CBR. From the BM lithography test, we found that the synthesized BFEA-polyester binder had better photocrosslinking capability and alkali solubility. In addition, the newly developed binder gave a good process margin, good resolution and adhesion property on a glass substrate.

• Membrane Journal
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• v.28 no.5
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• pp.326-331
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• 2018

Crosslinking of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) anion exchange membranes, which can be used for capacitive deionization (CDI), was investigated. PPO Anion exchange polymer was prepared through bromination and amination reaction steps and crosslinked with bisphenol A diglycidylether (BADGE), m-phenylenediamine (m-PDA), and hexamethylenediamine (HMDA). The gelation time by crosslinking was short in the order of HMDA > m-PDA > BADGE. The anion exchange membranes crosslinked at room temperature over a certain amount of crosslinking agent did not dissolve in an aprotic solvent such as 1-methylpyrrolidone (NMP) and the chemical durability of their membranes to organic solvent increased. The ion exchange capacity and water uptake of anion exchange membranes crosslinked with different crosslinker (BADGE) contents were measured and compared. The CDI performance of the crosslinked PPO anion exchange membrane immersed in the HMDA solution was almost the same as that of the non - crosslinked membrane except for the initial stage of the adsorption step.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.4
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• pp.616-624
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• 2018

In this study, a previous DNPH (2,4-dinitrophenylhydrazine) coupled with high performance liquid chromatography (HPLC) method to measure the concentration of formaldehyde in ambient and source environments has been improved. To improve the disadvantage of the previous HPLC method, an appropriate composition ratio of mobile phase (water: acetonitrile (ACN)) was determined and an isocratic analysis was conducted. Furthermore, limit of detection (LOD), limit of quantitation(LOQ), accuracy, and precision were investigated to verify the reliability of the analytical conditions determined. Finally, samples of exhaust gases from five different industrial facilities were applied to HPLC analytial method proposed to determine their formaldehyde concentrations. The appropriate composition ratio of the mobile phase under the isocratic condition was a mixture of water(40%) and ACN(60%). As the volume fraction of the organic solvent ACN increases, retention time of the formaldehyde peak was reduced. Detection time of formaldehyde peak determined using the proposed isocratic method was reduced from 7 minutes(previous HPLC method) to approximately 3 minutes. LOD, LOQ, accuracy, and precision of the formaldehyde determined using standard solutions were 0.787 ppm, 2.507 ppm, 93.1%, and 0.33%, respectively, all of which are within their recommended ranges. Average concentrations of the formaldehyde in five exhaust gases ranged from 0.054 ppm to 1.159 ppm. The lowest concentration (0.054 ppm) was found at samples from waste gas incinerator in a bisphenol-A manufacturing plant. The highest was observed at samples from the absorption process in manufacturing facilities of chemicals including formaldehyde and hexamine. The analytical time of the formaldehyde in ambient air can be shortened by using the isocratic analytical method under appropriate mobile phase conditions.

• Fisheries and Aquatic Sciences
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• v.8 no.4
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• pp.220-227
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• 2005

The estrogenic phenolic compounds, nonylphenol (NP), octylphenol(OP), bisphenol A (BPA) and nonylphenol mono- and diethoxylate ($NP_{1-2}EO$) were analyzed in 24 surface water samples from six rivers flowing into Masan Bay. All of the phenolic compounds were detected in all six rivers in high concentrations. The most abundant compound was $NP_{1-2}EO$ (86.0%), followed by NP ($10.1 \%$), BPA ($3.6\%$) and OP ($0.3\%$). The levels of phenolic compounds were 1.42-22.70 ${\mu}g$/L for $NP_{1-2}EO$, 0.15-1.68 ${\mu}g$/L for NP, 0.024-0.610 ${\mu}g$/L for BPA and 0.003-0.067 ${\mu}g$/L for OP. Especially, high concentrations were recorded in the rivers that pass through industrial complexes. The concentrations of phenolic compounds observed in these river waters were 1-2 orders of magnitude lower than the reported acute toxicity levels (hundreds of micrograms per liter). However, they were only slightly lower than the chronic toxicity levels. Most of the water samples also exceeded the Canadian nonylphenolic compounds water quality guideline, 1 ${\mu}g$/L, for the protection of aquatic life and the maximum permissible concentrations (MPC), 0.33 ${\mu}g$/L for NP and 0.12 ${\mu}g$/L for $NP_{1-2}EO$.

• Restorative Dentistry and Endodontics
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• v.24 no.4
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• pp.604-613
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• 1999

This study was performed to evaluate the effect of resin and filler type on the fracture toughness of light-activated composites. Experimental composites were prepared using urethane tetramethacrylate(UTMA) and bisphenol glycidylmethacrylate(Bis-GMA) monomers and five different types of silica fillers. Fracture toughness was measured by a single edge V-notched beam(SEVNB) method, which was discussed from ASTM E399-78. Rectangular bars of $2.5{\times}5{\times}26mm$ were prepared with experimental composites and a notch about 2.25mm deep was carved at the center of the long axis of the specimen using a dental diamond disk driven by a dental micro engine. The flexural test was carried out at a crosshead speed of 0.05mm/min and fracture surfaces were observed under scanning electron microscope. The results obtained were summarized as follows: 1. The fracture toughness values of UTMA-based composites were relatively higher than those of Bis-GMA-based composites. 2. The highest fracture toughness value was observed in the UTMA-based composite containing the $1.5{\mu}m$-spherical fillers. 3 Aging in the distilled water at $37^{\circ}C$ for 10 days showed the increase of fracture toughness, which was severer in the Bis-GMA-based composites than those of UTMA-based composites. 4. The AE amplitude occurring during the fracture toughness tests was the highest at the point of macroscopic fracture.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3706-3710
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• 2012

A novel silicon-containing arylacetylene resin (MSAR) modified by dipropargyl ether of bisphenol A (DPBPA) and dipropargyl ether of perfluorobisphenol A (DPPFBPA) was prepared separately. The curing behaviors of modified resins, DPBPA/MSAR and DPPFBPA/MSAR, were characterized with differential scanning calorimeter (DSC). The kinetic parameters of modified resins were obtained by the Kissinger and Ozawa methods. The results of dynamic mechanical analysis (DMA) revealed that the glass transition temperature ($T_g$) of the cured DPBPA/MSAR reached $486^{\circ}C$. According to the thermogravimetric analysis (TGA), the decomposition temperature ($T_{d5}$) of the cured resins and char yield ($Y_c$, $800^{\circ}C$) decreased as the dipropargyl ether loadings increased, especially in air. With the same weight loading, thermal stability of DPBPA/MSAR was better than that of DPPFBPA/MSAR. The carbon fiber (T300) reinforced composites exhibited excellent flexural properties at room temperature with a high property retention at $300^{\circ}C$.

• Journal of Adhesion and Interface
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• v.5 no.4
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• pp.17-23
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• 2004

In this study, we prepared the polycarbonates with various molecular weights by melt polymerization and investigated the crystallization by solvent induced crystallization. Effects of the types and compositions of solvents, crystallizing temperatures and molecular weights on crystallinity and melt temperatures of polycarbonates were evaluated by DSC, XRD and SEM. In case of low molecular weight polycarbonates and high crystallization temperature, the crystallinity of the polycarbonate was increased. As the increase of the crystallization temperature and the solution concentration, relatively uniform crystalline structures were obtained. Also, by treating with mixed solvents, the control of desired surface areas and crystallinity could be possible.

• YAKHAK HOEJI
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• v.53 no.4
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• pp.184-188
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• 2009

Fluorouracil (5-FU) is one of the most widely used chemotherapeutic drugs in the treatment of advanced colorectal cancer patients. Capsaicin (N-vanillyl-8-methyl-alpha-nonenamide), a spicy component of hot pepper, is a homovanillic acid derivative that preferentially induces cancer cells to undergo apoptosis. The purpose of the present study is to examine whether capsaicin enhances the anticancer effect of 5-fluorouracil in HT-29 human colon cancer cells by inducing apoptosis, and whether PPARgamma is involved in the capsaicin action in combination treatment with 5-FU. Treatment of the cells with either 5-FU or capsaicin alone for 48 h had little effect on the cell viability up to $50{\mu}M$ concentration, whereas co-treatment of the cells with capsaicin in the presence of 5-FU for 48 h significantly decreased the cell viability in a concentration-dependent manner. In addition, caspase-3 activity, a marker enzyme for apoptosis, was significantly increased by the combined treatment with 5-FU and capsaicin compared to the 5-FU or capsaicin alone treatment. Also, treatment with troglitazone, a peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$) agonist, further enhanced the effect of the combination treatment on the cell viability and caspase-3 activity, and bisphenol A diglycidyl ether (BADGE), a $PPAR{\gamma}$ antagonist, blocked the effect of the combination treatment. These results suggest that the combination treatment of HT-29 cells with 5-FU and capsaicin induces apoptotic cell death at relatively low concentration than each drug alone, and the combination treatment may be associated with the $PPAR{\gamma}$ pathway activation.

• Polymer(Korea)
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• v.33 no.4
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• pp.364-370
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• 2009

The curing kinetics and mechanical properties of siloxane-diaminodiphenylmethane (ETSO-DDM) on the two kinds of bisphenol (BPH) system which are DGEBA and DGEBF were investigated with the different contents of ETSO. To investigate the curing kinetics of the ETSO-DDM/BPH systems, differential scanning calorimeter (DSC) was used. The mechanical properties of ETSO-DDM/BPH systems were also examined by universal testing machine (UTM), tensile test and flexural test. From experimental results, the activation energies and mechanical properties of ETSO-DDM/BPH were improved with the decrease contents of ETSO. This was due to the high cross-linking density made from short length of ETSO-DDM, resulting in improving the mechanical inter-locking between ETSO-DDM and BPH in these systems.

• Restorative Dentistry and Endodontics
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• v.45 no.3
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• pp.32.1-32.12
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• 2020

Objectives: To evaluate the polymerization efficiency of a matrix-modified bulk-fill composite, and compare it to a conventional composite which has a similar filler system. The degree of conversion (DC%) and monomer elution were measured over different storage periods. Additionally, fillers' content was examined. Materials and Methods: Cylindrical specimens were prepared, in bulk and incrementally, from Filtek Bulk Fill (B) and Filtek Supreme XTE (S) composites using a Teflon mold, for each test (n = 6). Using attenuated total reflection method of Fourier transformation infrared spectroscopy, DC% was measured after 24 hours, 7 days, and 30 days. Using high-performance liquid chromatography, elution of hydroxyethyl methacrylate, triethylene glycol dimethacrylate, urethane dimethacrylate, and bisphenol-A glycidyl dimethacrylate was measured after 24 hours, 7 days and 30 days. Filler content was examined by scanning electron microscopy (SEM). Data were analyzed using 2-way mixed-model analysis of variance (α = 0.05). Results: There was no significant difference in DC% over different storage periods between B-bulk and S-incremental. Higher monomer elution was detected significantly from S than B. The elution quantity and rate varied significantly over storage periods and between different monomers. SEM images showed differences in fillers' sizes and agglomeration between both materials. Conclusions: Matrix-modified bulk-fill composites could be packed and cured in bulk with polymerization efficiency similar to conventional composites.