• Journal of Adhesion and Interface
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• v.19 no.1
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• pp.5-12
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• 2018

The purpose of this study is to evaluate the adhesive properties of polyurethane mixed aqueous dispersions by omitting the primer, dealing with the preparation of skins for synthetic leather with excellent adhesion by omitting the pre-treatment process. The two-component mixed polyurethane water dispersion was prepared by synthesizing an ester-based polyurethane resin (PU-T) and a carbonate-based polyurethane resin (PU-C) to obtain the final resin. As a result of measuring the peel strength of the adhesive specimens omitting the pre-treatment agent, it was confirmed that the state adhesive strength (ethylene vinyl acetate (middle): $4.2kg_f/cm$ and rubber (outsole): $4.4kg_f/cm$) there was. This makes it possible to omit the pre-treatment process which has been indispensably used in the shoe manufacturing process, thereby reducing the process time and reducing the amount of volatile organic compounds (VOCs) generated in the pre-treatment product, resulting in environmentally advantageous.

• Polymer(Korea)
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• v.33 no.6
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• pp.569-574
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• 2009

Organic- inorganic hybrid waterborne polyurethane (PUD) is synthesized by using hybrid polyol consist of carbonate (PCD), ester (PCL), and siloxane (PDSBP) in order to enhance anti-scratch property of PUD film. The diameter of graft type PUD emulsion is bigger than that of linear type PUD due to the graft structure of hydrophobic siloxane chain. The glass transition temperature of linear type PUD increase and the decomposition temperature of linear type PUD decrease with the content of PCD polyol. While, the decomposition temperature of graft type PUD almost same with increasing PDSBP content. The anti-scratch property and pencil hardness of graft type PUD improves as adding PDSBP polyol in the hybrid polyol system. When 9 wt% of PDSBP polyol is mixed, PUD films shows excellent anti-scratch property (~3.3 N), and pencil hardness (> 9 H).

• Polymer(Korea)
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• v.37 no.4
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• pp.431-436
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• 2013

Polycarbonate (PC) films have been irradiated with various kinds of ions according to energy and dose. Change of the optical transmittance and chemical characteristics were confirmed by UV-VIS and FTIR (ATR) spectroscopy respectively. These UV-A block in 400 nm was variable from 10 to 100% according to energy and doses. Surface electrical resistance of PC film irradiated by ion beam was $10^6-10^{13}{\Omega}/cm^2$, which reveal variation of conduction. Contact angle of film irradiated by ion beam was decreased than the pristine film. Polymer surface morphology was examined by means of atomic force microscopy (AFM). As expected, degradation of polymer film was higher after irradiation with heavier Xe ions but the roughness in the polymer surface morphology were more pronounced for Ar ions. This observed effect can be explained by stronger compaction of polymer surface layer in the case of Xe irradiation, connected with a reduction of free volume available.

• Polymer(Korea)
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• v.37 no.4
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• pp.437-441
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• 2013

A novel sulfonate flame retardant, 1,3,5,7-tetrakis(phenyl-4-sodium sulfonate)adamantane (FR-A), was successfully synthesized from 1-bromoadamantane in sequential four-step reactions involving Fiedel-Crafts phenylation, sulphonation, hydrolysis, and neutralization. The success of synthesis was confirmed by FTIR spectra, $^1H$ NMR spectra, elemental analyses and mass spectra. The effect of FR-A on the flame retardacy of polycarbonate (PC) has been studied. Limiting oxygen index (LOI) and thermogravimetric analysis (TGA) showed that this novel sulfonate flame retardant had effective flame retardancy on polycarbonate (PC). With a small amount (0.08 wt%) of FR-A, the flame retardancy of PC was improved obviously, which got to UL 94 V-0 rating. TGA and DTA curves demonstrated that the additive raised the degradation rate of PC by promoting the quick formation of an insulating carbon layer on the surface, and confirmed that the flame retardant mechanism of PC/FR-A system was similar to potassium diphenylsulfone sulfonate (KSS).

• Journal of the Korean Ceramic Society
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• v.35 no.8
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• pp.857-863
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• 1998

The BaTiO3 powders extensively used as MLCC (Multilayer ceramic capacitor) in electronic ceramic in-dustry were synthesized by GNP (Glycine-Nitrate process) The powders were prepared using carbonate and alkoxide as starting materials and nitric acid was used as a solvent for starting materials as well as an oxidant for combustion. The BaTiO3 powders were synthesized using different amounts of glycine as a fuel for combustion. The characteristics of synthesized powders were examined with helium pycnometer X-ray diffraction(XRD) Brunauer-Emmett-Teller with N2 adsorption and scanning electron microscopy(SEM). It was found that single phase BaTiO3 could be formed when the as-synthesized powders were heat-treated at 100$0^{\circ}C$ When the glycine/cation molar ratio was 1,2 specific surface area was 24m2/g

• Journal of Energy Engineering
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• v.23 no.2
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• pp.217-222
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• 2014

In order to improve the heat efficiency of the general residential boiler, we performed an experiment of condensation heat transfer to air pre-heating exchanger adhered to the condensing boiler. In this study, surface roughness was imposed on the surface of stainless steel by etching. And in order to evaluate the heat transfer performance on each plate, the counter flow heat exchanger fabricated with polycarbonate in used. As a result, on etching treated plate's overall heat transfer coefficient is higher than the original plate. And etching treated plate during 60 seconds with etchant is the to average 15% compared to bare stainless steel. And we studied the heat transfer enhancement factor through the analysis of surface characteristics using AFM.

• Korean Journal of Microbiology
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• v.54 no.3
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• pp.302-304
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• 2018

We, for the first time, isolated and identified a Vibrio splendidus KCTC 11899BP producing hyaluronate lyase from seawater. This enzyme is produced only when hyaluronic acid (HA) is added to the basal medium. Hyaluronate lyases are produced by microorganisms, which degrade the ${\beta}$-(1, 4) bond of HA to produce disaccharide. The genome of KCTC 11899BP, which consist of two circular contigs that are 3,522 kb (contig 1) long and 1,986 kb (contig 2) long respectively, as like other Vibrio sp. that contained 2 chromosomes. The genome included 4,700 predicted open reading frames, G + C content 44.12%, 137 tRNA genes, and 46 rRNA genes.

• Applied Chemistry for Engineering
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• v.19 no.3
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• pp.287-294
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• 2008

Molecularly imprinted polymer (MIPs) membranes were prepared by UV polymerization to separate racemates with opposite physiological activity, and then its separation selectivity of racemates was carried out. Likewise, their properties were examined. Polycarbonate (PC) membrane was polymerized as small spot form in pore inner wall, but anodisc (AD) membrane was polymerized as film form with thickness 500~700 nm onto the membrane surface. Also the study on the separation selectivity of prepared MIPs membranes was carried out in L-Tryptophane (Trp) racemate solution. The results showed that AD MIPs membrane polymerized as a film form, which was achieved by solution polymerizaion consisting of over 90% cross-linking agent (ethylene glycol dimethacrylate; EGDMA) and under 30% dispersing agent (methanol; MeOH), had predominant 3.5 selectivity.

• Journal of Adhesion and Interface
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• v.4 no.1
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• pp.9-17
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• 2003

The UV hard coating materials are attracting more and more attention to modern industry, in terms of the development of low or non solvent coating materials which will contribute to economizing both materials and energy and to reducing pollution. This study was performed in order to invent UV curable coating materials containing colloidal silica which have actual industrial applications. As results of experiments, the oligomers type and the concentration of colloidal silica acrylate oligomer (SAOC) have an influence on various especially, The properties of UV hardening cooling, such as chemical, abrasion resistance and weatherability, were greatly enhanced, the impact properties of coated polycarbonate substrate were improved compared with the noncoated that. The UV cured films containing 30 wt% SAOC obtained showed the best properties.

• Journal of the Korean Society of Radiology
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• v.15 no.6
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• pp.869-875
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• 2021

The purpose of this study is to derive a formula for calculating the effective energy of an X-ray beam generated by a CT simulator. Under 90, 120, and 140 kVp X-ray beams, the CT number calibration insert part of the AAPM CT performance phantom was scanned 5 times with a CT simulator. The CT numbers of polyethylene, polystyrene, water, nylon, polycarbonate, and acrylic were measured for each CT slice image. The average value of CT number measured under a single tube voltage and the linear attenuation coefficients corresponding to each photon energy calculated from the data of the National Institute of Standards and Technology were linearly fitted. Among the obtained correlation coefficients, the photon energy having the maximum value was determined as the effective energy. In this way, the effective energy of the X-ray beam generated at each tube voltage was determined. By linearly fitting the determined effective energies(y) and tube voltages(x), y=0.33026x+30.80263 as an effective energy calculation formula was induced.