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A less-toxic and durable flame-retardant treatment for cotton fabrics was developed using a blocked isocyanate (MDI), citric acid (CA) as a cross-linker, and 3-(dimethylphosphono)-N-methylolpropionamide (MDPPA) as a fire-retardant agent. Treated samples were prepared using the pad–dry–cure method, in which cotton fabric samples were immersed in solutions containing various ratios of MDPPA/CA/MDI. The chemical structures of the treated cotton fabrics, as well as the flame retardancy, thermal stability, physicochemical properties, and durability of the flame-retardant effect to washing, were investigated. The treated cotton fabrics showed different flame retardancies depending on the ratio of components in the flame-retardant treatment, and, thus, the optimal ratio was determined. Using Fourier transform infrared and X-ray photoelectron spectroscopy analyses, we confirmed that MDPPA was attached to the cotton fibers. In addition, vertical flame-retardancy tests were performed on samples before and after washing and the limiting oxygen index values were obtained. Based on the tests, the sample treated with a mixture containing 400, 40, and 50 g/L of MDPPA, CA, and MDI, respectively, showed the best fire resistance, even after 50 washing cycles, and the tear strength, crease recovery angle, and flame retardancy were all improved compared to those of the untreated sample.
Hyeji Jeon; Jaewoong Lee; Jongyoung Park; Chankyu Kang. Eco-friendly, less toxic, and washing-durable flame-retardant finishing for cotton fabrics using a blocked isocyanate and 3-(dimethylphosphono)-N-methylolpropionamide. Materials Chemistry and Physics 2021, 273, 125149 .
AMA StyleHyeji Jeon, Jaewoong Lee, Jongyoung Park, Chankyu Kang. Eco-friendly, less toxic, and washing-durable flame-retardant finishing for cotton fabrics using a blocked isocyanate and 3-(dimethylphosphono)-N-methylolpropionamide. Materials Chemistry and Physics. 2021; 273 ():125149.
Chicago/Turabian StyleHyeji Jeon; Jaewoong Lee; Jongyoung Park; Chankyu Kang. 2021. "Eco-friendly, less toxic, and washing-durable flame-retardant finishing for cotton fabrics using a blocked isocyanate and 3-(dimethylphosphono)-N-methylolpropionamide." Materials Chemistry and Physics 273, no. : 125149.
The commercialization of eco-friendly hydrogen vehicles has elicited attempts to expand hydrogen refueling stations in urban areas; however, safety measures to reduce the risk of jet fires have not been established. The RISKCURVES software was used to evaluate the individual and societal risks of hydrogen refueling stations in urban areas, and the F–N (Frequency–Number of fatalities) curve was used to compare whether the safety measures satisfied international standards. From the results of the analysis, it was found that there is a risk of explosion in the expansion of hydrogen refueling stations in urban areas, and safety measures should be considered. To lower the risk of hydrogen refueling stations, this study applied the passive and active independent protection layers (IPLs) of LOPA (Layer of Protection Analysis) and confirmed that these measures significantly reduced societal risk as well as individual risk and met international standards. In particular, such measures could effectively reduce the impact of jet fire in dispensers and tube trailers that had a high risk. Measures employing both IPL types were efficient in meeting international standard criteria; however, passive IPLs were found to have a greater risk reduction effect than active IPLs. The combination of RISKCURVES and LOPA is an appropriate risk assessment method that can reduce work time and mitigate risks through protective measures compared to existing risk assessment methods. This method can be applied to risk assessment and risk mitigation not only for hydrogen facilities, but also for hazardous materials with high fire or explosion risk.
Byoungjik Park; Yangkyun Kim; Kwanwoo Lee; Shinwon Paik; Chankyu Kang. Risk Assessment Method Combining Independent Protection Layers (IPL) of Layer of Protection Analysis (LOPA) and RISKCURVES Software: Case Study of Hydrogen Refueling Stations in Urban Areas. Energies 2021, 14, 4043 .
AMA StyleByoungjik Park, Yangkyun Kim, Kwanwoo Lee, Shinwon Paik, Chankyu Kang. Risk Assessment Method Combining Independent Protection Layers (IPL) of Layer of Protection Analysis (LOPA) and RISKCURVES Software: Case Study of Hydrogen Refueling Stations in Urban Areas. Energies. 2021; 14 (13):4043.
Chicago/Turabian StyleByoungjik Park; Yangkyun Kim; Kwanwoo Lee; Shinwon Paik; Chankyu Kang. 2021. "Risk Assessment Method Combining Independent Protection Layers (IPL) of Layer of Protection Analysis (LOPA) and RISKCURVES Software: Case Study of Hydrogen Refueling Stations in Urban Areas." Energies 14, no. 13: 4043.
CPVC fibers were prepared using a low-cost chlorinate polyvinyl chloride (CPVC) precursor using wet spinning, and various elongation rates were applied (0%, 50%, 100%, and 125%) to improve the physicochemical properties. CPVC fibers were carbonized in a nitrogen atmosphere to prepare CPVC carbon fibers, and physicochemical changes were observed by applying the same elongation rates. The CPVC fiber changed from aliphatic to aromatic carbon chemically, such as C-Cl peak intensity disappeared after carbonization and C=C bonding peak was newly discovered. After CPVC carbonization, CPVC carbon fiber, which has an elongation of 125%, has the maximum mechanical properties (tensile strength of up to 1.83GPa, modulus of 172GPa) by inducing a change in the carbon fiber structure, so it can be applied to the automotive industry in the future.
Jiyeon Kim; Jaewoong Lee; Chaehyun Jo; Chankyu Kang. Development of low cost carbon fibers based on chlorinated polyvinyl chloride(CPVC) for automotive applications. Materials & Design 2021, 204, 109682 .
AMA StyleJiyeon Kim, Jaewoong Lee, Chaehyun Jo, Chankyu Kang. Development of low cost carbon fibers based on chlorinated polyvinyl chloride(CPVC) for automotive applications. Materials & Design. 2021; 204 ():109682.
Chicago/Turabian StyleJiyeon Kim; Jaewoong Lee; Chaehyun Jo; Chankyu Kang. 2021. "Development of low cost carbon fibers based on chlorinated polyvinyl chloride(CPVC) for automotive applications." Materials & Design 204, no. : 109682.
The effects of supercritical CO2 and C.I. Disperse Red 167 as media on the structural and chemical properties of polyethylene terephthalate (PET) fibers were observed in the supercritical dyeing process of these fibers using numerous methods to predict changes in their physical properties. PET samples were classified into three cases based on the sample preparation and analysis steps. When the PET fibers were treated without C.I. Disperse Red 167 under a supercritical fluid CO2 solvent at 120 °C and 25 MPa, their crystallinity, orientation, and tensile strength decreased the most among the three cases, whereas when they were treated with C.I. Disperse Red 167 under the same conditions, the three above-mentioned characteristics were relatively improved compared to the scenario without the C.I. Disperse Red 167 treatment. These experimental results provided significant information on the effects of supercritical CO2 and C.I. Disperse Red 167 on the properties of PET fiber polymers.
Jiyeon Oh; Sam Soo Kim; Kyoung Hou Kim; Jaewoong Lee; Chankyu Kang. Structural and physico-chemical properties change of polyethylene terephthalate (PET) fibers after supercritical fluid dyeing with C.I. disperse red 167. The Journal of Supercritical Fluids 2020, 170, 105131 .
AMA StyleJiyeon Oh, Sam Soo Kim, Kyoung Hou Kim, Jaewoong Lee, Chankyu Kang. Structural and physico-chemical properties change of polyethylene terephthalate (PET) fibers after supercritical fluid dyeing with C.I. disperse red 167. The Journal of Supercritical Fluids. 2020; 170 ():105131.
Chicago/Turabian StyleJiyeon Oh; Sam Soo Kim; Kyoung Hou Kim; Jaewoong Lee; Chankyu Kang. 2020. "Structural and physico-chemical properties change of polyethylene terephthalate (PET) fibers after supercritical fluid dyeing with C.I. disperse red 167." The Journal of Supercritical Fluids 170, no. : 105131.
Risk management of major hazardous installations (MHIs) is a principal concern due to chemical hazards, both in South Korea and in foreign countries where chemical plants are located. To cope with these risks, various regulatory schemes have been developed for the recognition, prevention, and control of chemical accidents. Despite these efforts, the worst major accident caused by massive (20 t) leakage of anhydrous hydrogen fluoride occurred in Gumi City in 2012. As a result, the location of MHIs associated with the chemical industry became a major concern among the public, relating to the risks to both the public and environment. In this study, the regulatory systems in South Korea are compared with global standards for controlling major hazards, and the adoption of land use planning (LUP) is discussed. Based on population statistics for the last 17 years, the EPA's ALOHA software was used to evaluate the impact of land development and population growth around MHIs through case studies of societal risk changes at five water-treatment plants using Cl2 (chlorine). The total risk at the Cl2 sites increased by up to 3.05 times from 2000 to 2017, demonstrating the necessity of introducing LUP.
Seungkyoo Pak; Chankyu Kang. Increased risk to people around major hazardous installations and the necessity of land use planning in South Korea. Process Safety and Environmental Protection 2020, 149, 325 -333.
AMA StyleSeungkyoo Pak, Chankyu Kang. Increased risk to people around major hazardous installations and the necessity of land use planning in South Korea. Process Safety and Environmental Protection. 2020; 149 ():325-333.
Chicago/Turabian StyleSeungkyoo Pak; Chankyu Kang. 2020. "Increased risk to people around major hazardous installations and the necessity of land use planning in South Korea." Process Safety and Environmental Protection 149, no. : 325-333.
Computational fluid dynamic (CFD) simulations were performed to assess the potential chlorine leak scenario in the super-urban area of South Korea, where the human population density is very high and numerous buildings exist near operational water treatment facilities. Flame acceleration simulator (FLACS) was used to predict the consequence from accidental chlorine releases out of one of the water treatment facilities for the nearby area having a size of 5 km × 3 km approximately. The ability to precisely implement 3-D geometries is crucial for a successful 3-D simulation. Thus, a method was proposed to rapidly and accurately implement geometry by importing computer aided-design (CAD) files provided by a government agency, and processing them using Auto CAD and MicroStation software programs. An accidental release from an 18-ton tank was simulated with three different wind directions to determine the expected evacuation distances. Results from the study showed that the endpoint distances varied depending on the density and arrangement of the buildings. Moreover, we employed physical barriers with varying heights for mitigating the effects of toxic gas releases and simulated how effectively they decreased the concentration of released chlorine.
Mimi Min; Junyong Park; Chankyu Kang; Seungho Jung. 3-D dispersion model for simulation of accidental toxic gas releases in a metropolitan area. Journal of Loss Prevention in the Process Industries 2020, 69, 104337 .
AMA StyleMimi Min, Junyong Park, Chankyu Kang, Seungho Jung. 3-D dispersion model for simulation of accidental toxic gas releases in a metropolitan area. Journal of Loss Prevention in the Process Industries. 2020; 69 ():104337.
Chicago/Turabian StyleMimi Min; Junyong Park; Chankyu Kang; Seungho Jung. 2020. "3-D dispersion model for simulation of accidental toxic gas releases in a metropolitan area." Journal of Loss Prevention in the Process Industries 69, no. : 104337.
Industrial accidents caused by equipment (machinery) occur in various forms, such as jamming, cutting, and crushing. Among them, various precise and dangerous machines and equipment in the manufacturing industry continue to be used despite the several regulations established and efforts made. This study analysed the accidental deaths caused through jamming or crushing during non-routine work, in the manufacturing industry from 2014 to 2018. The analysis was conducted on 203 cases of non-routine work among 359 fatalities. The maintenance, repair, inspection, replacement, adjustment, cleaning, and removal of foreign substances were classified into non-routine work. Owing to the use of various machineries and equipment in the manufacturing industry, specialised knowledge is required for their maintenance and management, as well as daily work. Since various types of equipment (machinery) are used in the manufacturing industry, expertise to safely use equipment is required to prevent industrial accidents that may occur during work using this equipment. In South Korea, where heavy industry and chemical industry have developed, many accidental deaths due to non-routine work have been reported under these conditions. Non-routine work accounted for 56.5% of jamming accidents, which were caused by seven major equipment such as conveyor, mixer, food manufacturing equipment, crushing machine, injection moulding machine, press machine, and industrial robot. In addition, the employees did not fully comply with the basic safety rules, such as not turning off the power or using lockout-tagout (LOTO), during the maintenance work. Finally, various measures were proposed to prevent accidental deaths resulting non-routine work.
Sanghyun Kim; Jungmo Lee; Chankyu Kang. Analysis of industrial accidents causing through jamming or crushing accidental deaths in the manufacturing industry in South Korea: Focus on non-routine work on machinery. Safety Science 2020, 133, 104998 .
AMA StyleSanghyun Kim, Jungmo Lee, Chankyu Kang. Analysis of industrial accidents causing through jamming or crushing accidental deaths in the manufacturing industry in South Korea: Focus on non-routine work on machinery. Safety Science. 2020; 133 ():104998.
Chicago/Turabian StyleSanghyun Kim; Jungmo Lee; Chankyu Kang. 2020. "Analysis of industrial accidents causing through jamming or crushing accidental deaths in the manufacturing industry in South Korea: Focus on non-routine work on machinery." Safety Science 133, no. : 104998.
Major accidents in the chemical process industries are relatively rare, but the resulting harm to workers, property loss, business interruption, and the environment are very serious. This study investigates chemical accidents that occurred between January 2008 and June 2018 in South Korea, and proposes ways to prevent similar accidents from occurring by analyzing the main causes of these accidents. Nine core concepts were drawn from the analyses comparing chemical accidents in South Korea: (1) current casualties by type of worker, (2) how the scale of the enterprise affects the disaster, (3) chemical accidents by type of occurrence, (4) analysis of ignition sources, (5) chemical accidents by CPI facilities, (6) human and technical error, (7) chemical accidents by work situation, (8) chemical accidents by non-compliance of process safety management (PSM) standards, and (9) chemical accidents by hazardous materials. Although there have been no recent occurrences of large chemical accidents since 2017 due to various factors, our results indicate that the past frequency of such accidents area serious concern in South Korea. Understanding the root causes of these accidents can help to prevent the recurrence of similar accidents and to strengthen preventative measures in chemical plants.
Seungho Jung; Jongkwon Woo; Chankyu Kang. Analysis of severe industrial accidents caused by hazardous chemicals in South Korea from January 2008 to June 2018. Safety Science 2020, 124, 104580 .
AMA StyleSeungho Jung, Jongkwon Woo, Chankyu Kang. Analysis of severe industrial accidents caused by hazardous chemicals in South Korea from January 2008 to June 2018. Safety Science. 2020; 124 ():104580.
Chicago/Turabian StyleSeungho Jung; Jongkwon Woo; Chankyu Kang. 2020. "Analysis of severe industrial accidents caused by hazardous chemicals in South Korea from January 2008 to June 2018." Safety Science 124, no. : 104580.
Using personal protective equipment, such as safety helmets, at industrial sites, is the last method to prevent disasters, and such equipment are widely recognized as consumables. Among them, industrial safety helmets use ABS (acrylonitrile butadiene styrene) or PE (polyethylene) resins as the main material of the shell to absorb shocks, and they also possess a relatively good heat resistance. However, efforts to develop new materials by a simple fabrication method are not actively performed. In this study, to improve the safety performance of industrial helmets, an epoxy resin was used as a matrix to produce a p-aramid/carbon fiber composite as a simple cross-ply, and compared to p-aramid fiber-reinforced composites, carbon fiber-reinforced composites, and ABS plastic. The specimens were prepared by the compression molding method, and their mechanical properties including the impact strength, tensile strength, flexural strength, and inter-laminar shear strength along with heat resistance properties were observed via thermogravimetric analysis.
Sanghyun Kim; Jaewoong Lee; Changhyun Roh; Jonghyun Eun; Chankyu Kang. Evaluation of carbon fiber and p-aramid composite for industrial helmet using simple cross-ply for protecting human heads. Mechanics of Materials 2019, 139, 103203 .
AMA StyleSanghyun Kim, Jaewoong Lee, Changhyun Roh, Jonghyun Eun, Chankyu Kang. Evaluation of carbon fiber and p-aramid composite for industrial helmet using simple cross-ply for protecting human heads. Mechanics of Materials. 2019; 139 ():103203.
Chicago/Turabian StyleSanghyun Kim; Jaewoong Lee; Changhyun Roh; Jonghyun Eun; Chankyu Kang. 2019. "Evaluation of carbon fiber and p-aramid composite for industrial helmet using simple cross-ply for protecting human heads." Mechanics of Materials 139, no. : 103203.
Despite recent extensive research and technical development to prevent and mitigate dust explosions, processes that produce and handle combustible materials in the form of powders and dusts, either as a main product or as an undesired by-product, have become a constant dust explosion threat as they become more sophisticated and complicated. This study analyzed the characteristics of 53 dust explosions that occurred in South Korea over the last 30 years, and investigated the differences of dust explosions that happened in various countries, such as Japan, the United States, the United Kingdom, and France. In addition, case studies showed the severity of dust explosions occurring in South Korea. Through the special focus on the three most recent years of dust explosions, the causes and processes of the accidents were identified. Analyses of dust explosions in South Korea show that they were mainly caused by organic matter and metal, and, unfortunately, dust explosions occurred repeatedly during grinding, mixing, and injection of powder materials into facilities. No reported accidents occurred during the production processes of wood or paper during the last three years. Taking these characteristics into account, effective ways to prevent or mitigate dust explosions at workplaces where many dust explosions occurred were suggested.
Seonggyu Pak; Seongho Jung; Changhyun Roh; Chankyu Kang. Case Studies for Dangerous Dust Explosions in South Korea during Recent Years. Sustainability 2019, 11, 4888 .
AMA StyleSeonggyu Pak, Seongho Jung, Changhyun Roh, Chankyu Kang. Case Studies for Dangerous Dust Explosions in South Korea during Recent Years. Sustainability. 2019; 11 (18):4888.
Chicago/Turabian StyleSeonggyu Pak; Seongho Jung; Changhyun Roh; Chankyu Kang. 2019. "Case Studies for Dangerous Dust Explosions in South Korea during Recent Years." Sustainability 11, no. 18: 4888.
In this study, the antimicrobial and photodegradation properties of nylon fabric were improved by chemical treatment using 3-mercaptopropyltrimethoxysilane (3-MPTMS), which binds to photocatalyst TiO2, on a nylon fabric surface. The nylon fibers were impregnated with a solution containing isopropanol, titanium dioxide (TiO2), and 3-MPTMS at optimum ratios, and then stirred for 90 min. To remove the nonreactive impurities, the sample was washed twice with isopropanol and distilled water, and then dried. The TiO2 concentration, agitation temperature, and time were varied to determine suitable coating conditions for attachment to the nylon surface; the resulting properties were confirmed by scanning electron microscopy/energy dispersive spectroscopy. To evaluate the antimicrobial and photodegradation properties of TiO2, antimicrobial tests were conducted using the microbial reduction method and contact angle tests. The fiber contamination rate was measured by computer color matching after the sample was contaminated with methylene blue. Moreover, the antimicrobial activity of Staphylococcus aureus and Escherichia coli strains on the treated nylon was investigated.
Gyoyoung Lee; Jaewoong Lee; Chankyu Kang. Strong and sustainable chemical bonding of TiO2 on nylon surface using 3-mercaptopropyltrimethoxysilane (3-MPTMS): analysis of antimicrobial and decomposition characteristics of contaminants. Journal of Coatings Technology and Research 2019, 16, 1399 -1409.
AMA StyleGyoyoung Lee, Jaewoong Lee, Chankyu Kang. Strong and sustainable chemical bonding of TiO2 on nylon surface using 3-mercaptopropyltrimethoxysilane (3-MPTMS): analysis of antimicrobial and decomposition characteristics of contaminants. Journal of Coatings Technology and Research. 2019; 16 (5):1399-1409.
Chicago/Turabian StyleGyoyoung Lee; Jaewoong Lee; Chankyu Kang. 2019. "Strong and sustainable chemical bonding of TiO2 on nylon surface using 3-mercaptopropyltrimethoxysilane (3-MPTMS): analysis of antimicrobial and decomposition characteristics of contaminants." Journal of Coatings Technology and Research 16, no. 5: 1399-1409.
Recently, the impact of radioactive caesium (Cs) and strontium (Sr) on human health and the ecosystem has been a major concern due to the use of nuclear energy. However, this study observed changes in green-fluorescent (GFP)-tagged Pseudomonas aeruginosa PAO1 biofilms by injecting non-radioactive caesium chloride (CsCl) and strontium chloride (SrCl 2 ) into microstructures embedded in polydimethylsiloxane microfluidic devices, which were used due to their strong toxicity limitations. Four types of microstructures with two different diameters were used in the study. The change of biofilm thickness from fluid velocity and wall shear stress was estimated using computational fluid dynamics and observed throughout the experiment. The effect of pore space became a significant physical factor when the fluid was flowing through the microfluidic devices. As the pore space increased, the biofilm growth increased; therefore, triangular microstructures with the largest pore space showed the best growth of biofilm. Caesium chloride (CsCl) and strontium chloride (SrCl 2 ), less toxic than radioactive caesium (Cs) and strontium (Sr), completely eradicated the P. aeruginosa PAO1 biofilm with low concentrations. The combined effect of toxicity, fluid velocity, wall shear stress and microstructures increased the efficiency of biofilm eradication. These findings on microfluidic chips can help to indirectly predict the impact on human public health and ecosystems without using radioactive chemicals.
Changhyun Roh; Thi Toan Nguyen; Jae-Jin Shim; Chankyu Kang. Physico-chemical characterization of caesium and strontium using fluorescent intensity of bacteria in a microfluidic platform. Royal Society Open Science 2019, 6, 182069 .
AMA StyleChanghyun Roh, Thi Toan Nguyen, Jae-Jin Shim, Chankyu Kang. Physico-chemical characterization of caesium and strontium using fluorescent intensity of bacteria in a microfluidic platform. Royal Society Open Science. 2019; 6 (5):182069.
Chicago/Turabian StyleChanghyun Roh; Thi Toan Nguyen; Jae-Jin Shim; Chankyu Kang. 2019. "Physico-chemical characterization of caesium and strontium using fluorescent intensity of bacteria in a microfluidic platform." Royal Society Open Science 6, no. 5: 182069.
With excellent heat resistance and chemical resistance, p-aramid is used in a variety of industrial applications. In this study, the polyimide (PI) precursor was coated on the surface of p-aramid yarn and studied the changes in heat resistance and physicochemical properties of composite PI / p-aramid yarns. Changes in peaks by imidization of PI using XRD and FT-IR, surface characteristics through SEM, and thermal properties analyzed by TMA and TG-DTA were measured. The degree of imidization of PI films were quantitatively investigated by FT-IR analysis. Through these analyzes, the following results were revealed: (1) the imidization of the PI was confirmed that the thermal imidization process at 350 °C was suitable; (2) the physical properties of the PI film were affected by the imidization temperature, the heat treatment time and the amount of the catalyst; and (3) the tensile strength of PI / p-aramid coated yarn was higher than that of conventional uncoated p-aramid yarn at 200–350 °C. Therefore, PI/ p-aramid composite yarns formed through the stepwise coating were found to improve thermal properties including initial thermal degradation temperature compared to no PI coating.
Jaewoong Lee; Sam Soo Kim; Dakyung Kang; Changhyun Roh; Chankyu Kang. Physicochemical characterization of polyimide (PI) / p-aramid: New functional and safe materials with improved heat resistance by a simple coating of polyimide on the surface of p-aramid. Progress in Organic Coatings 2018, 127, 117 -123.
AMA StyleJaewoong Lee, Sam Soo Kim, Dakyung Kang, Changhyun Roh, Chankyu Kang. Physicochemical characterization of polyimide (PI) / p-aramid: New functional and safe materials with improved heat resistance by a simple coating of polyimide on the surface of p-aramid. Progress in Organic Coatings. 2018; 127 ():117-123.
Chicago/Turabian StyleJaewoong Lee; Sam Soo Kim; Dakyung Kang; Changhyun Roh; Chankyu Kang. 2018. "Physicochemical characterization of polyimide (PI) / p-aramid: New functional and safe materials with improved heat resistance by a simple coating of polyimide on the surface of p-aramid." Progress in Organic Coatings 127, no. : 117-123.
Dajeong Ahn; Jaewoong Lee; Chankyu Kang. Physico-chemical properties of new composite polymer for heat resistance with thin-film form through the blending of m-aramid and polyurethane (PU). Polymer 2018, 138, 17 -23.
AMA StyleDajeong Ahn, Jaewoong Lee, Chankyu Kang. Physico-chemical properties of new composite polymer for heat resistance with thin-film form through the blending of m-aramid and polyurethane (PU). Polymer. 2018; 138 ():17-23.
Chicago/Turabian StyleDajeong Ahn; Jaewoong Lee; Chankyu Kang. 2018. "Physico-chemical properties of new composite polymer for heat resistance with thin-film form through the blending of m-aramid and polyurethane (PU)." Polymer 138, no. : 17-23.
Dajeong Ahn; Jaewoong Lee; Changhyun Roh; Inhwan Sul; Chankyu Kang. Comparative analysis between gamma-irradiation and three chemical disinfectants using antibacterial efficacy and tensile strength of polymers. Journal of Cleaner Production 2018, 172, 847 -854.
AMA StyleDajeong Ahn, Jaewoong Lee, Changhyun Roh, Inhwan Sul, Chankyu Kang. Comparative analysis between gamma-irradiation and three chemical disinfectants using antibacterial efficacy and tensile strength of polymers. Journal of Cleaner Production. 2018; 172 ():847-854.
Chicago/Turabian StyleDajeong Ahn; Jaewoong Lee; Changhyun Roh; Inhwan Sul; Chankyu Kang. 2018. "Comparative analysis between gamma-irradiation and three chemical disinfectants using antibacterial efficacy and tensile strength of polymers." Journal of Cleaner Production 172, no. : 847-854.
Functional p-aramid fibers that can express antimicrobial activity were produced by simple processing of silver nanoparticles (AgNPs), which are well known as antimicrobial agents, by using glycidyltrimethylammonium chloride (GTAC), a quaternary ammonium salt. P-aramid fibers were treated with GTAC by the pad-dry-cure process and put into an Ag colloid solution for reactions at 40 °C for 90 min to prepare GTAC/AgNPs-treated p-aramid fibers. Through these processes, GTAC was used as a substitute for existing cross-linking agents. The changes in the degree of attachment of AgNPs to the surface of p-aramid fibers were determined using a scanning electron microscope according to parameters such as GTAC concentration, Ag colloid concentration, and reaction temperature. Through this study, the following results were obtained: (i) The tensile strength of AgNPs/GTAC-treated p-aramid fibers was found to be about 80% of that of untreated p-aramid fibers; (ii) Thermogravimetric analysis showed that the thermal stability of p-aramid fibers did not change much after GTAC/AgNPs treatment and (iii) Antimicrobial activity analysis showed that AgNPs/GTAC-treated p-aramid fibers exhibited superior antibacterial properties compared to untreated p-aramid fibers, which may or may not be the effect of GTAC or AgNPs, or both.
Chankyu Kang; Dajeong Ahn; Changhyun Roh; Sam Soo Kim; Jaewoong Lee. Development of Synergistic Antimicrobial Coating of p-Aramid Fibers Using Ag Nanoparticles and Glycidyltrimethylammonium Chloride (GTAC) without the Aid of a Cross-Linking Agent. Polymers 2017, 9, 357 .
AMA StyleChankyu Kang, Dajeong Ahn, Changhyun Roh, Sam Soo Kim, Jaewoong Lee. Development of Synergistic Antimicrobial Coating of p-Aramid Fibers Using Ag Nanoparticles and Glycidyltrimethylammonium Chloride (GTAC) without the Aid of a Cross-Linking Agent. Polymers. 2017; 9 (12):357.
Chicago/Turabian StyleChankyu Kang; Dajeong Ahn; Changhyun Roh; Sam Soo Kim; Jaewoong Lee. 2017. "Development of Synergistic Antimicrobial Coating of p-Aramid Fibers Using Ag Nanoparticles and Glycidyltrimethylammonium Chloride (GTAC) without the Aid of a Cross-Linking Agent." Polymers 9, no. 12: 357.
Functional poly(m-phenylene isophthalamide), m-aramid (known as Nomex®) fibers with antimicrobial properties were prepared by applying quaternary ammonium salts (such as glycidyltrimethylammonium chloride (GTAC)) in combination with silver nanoparticles (AgNPs). The fibers treated by this simple process exhibited enhanced antimicrobial activity. In the coating process, the m-aramid fibers were immersed in a GTAC solution and reacted via the pad-dry-cure process. The GTAC-treated m-aramid fibers were then reacted with an Ag colloid solution at 40 °C for 90 min to prepare GTAC/AgNP-treated m-aramid fibers. Scanning electron microscopy was used to confirm the surface morphology of the m-aramid fibers treated with GTAC and AgNPs. Changes in the chemical composition before and after GTAC and AgNP treatment were analyzed by scanning electron microscopy with energy-dispersive X-ray spectroscopy. The tensile strength of the GTAC/AgNP-treated m-aramid fibers declined by about 3.5% compared to that of untreated m-aramid fibers. Durability of the AgNPs on the m-aramid fibers treated with GTAC/AgNPs was demonstrated through a washing-fastness test, indicating 76% retention after five washing cycles. The antimicrobial activity analysis showed that the synergistic antimicrobial properties of the GTAC/AgNP-treated m-aramid fibers resulted in efficacy against P. aeruginosa.
Chankyu Kang; Sam Soo Kim; Dajeong Ahn; Soo Jung Kim; Jaewoong Lee. Effective surface attachment of Ag nanoparticles on fibers using glycidyltrimethylammonium chloride and improvement of antimicrobial properties. RSC Advances 2017, 7, 23407 -23414.
AMA StyleChankyu Kang, Sam Soo Kim, Dajeong Ahn, Soo Jung Kim, Jaewoong Lee. Effective surface attachment of Ag nanoparticles on fibers using glycidyltrimethylammonium chloride and improvement of antimicrobial properties. RSC Advances. 2017; 7 (38):23407-23414.
Chicago/Turabian StyleChankyu Kang; Sam Soo Kim; Dajeong Ahn; Soo Jung Kim; Jaewoong Lee. 2017. "Effective surface attachment of Ag nanoparticles on fibers using glycidyltrimethylammonium chloride and improvement of antimicrobial properties." RSC Advances 7, no. 38: 23407-23414.
This paper describes the use of an analytical microfluidic sensor for accelerating chemo-repellent response and strong anti-bacterial 1-(Thien-2-yl)-3-(2, 6-difluoro phenyl) prop-2-en-1-one (1-TDPPO). The chemically-synthesized antimicrobial agent, which included prop-2-en-1-one and difluoro phenyl groups, was moving through an optically transparent polydimethylsiloxane (PDMS) microfluidic sensor with circular obstacles arranged evenly. The response, growth and distribution of fluorescent labeling Pseudomonas aeruginosa PAO1 against the antimicrobial agent were monitored by confocal laser scanning microscope (CLSM). The microfluidic sensor along with 1-TDPPOin this study exhibits the following advantages: (i) Real-time chemo-repellent responses of cell dynamics; (ii) Rapid eradication of biofilm by embedded obstacles and powerful antibacterial agents, which significantly reduce the response time compared to classical methods; (iii) Minimal consumption of cells and antimicrobial agents; and (iv) Simplifying the process of the normalization of the fluorescence intensity and monitoring of biofilm by captured images and datasets.
Changhyun Roh; Jaewoong Lee; Mayank Kinger; Chankyu Kang. In Vitro Studies on a Microfluidic Sensor with Embedded Obstacles Using New Antibacterial Synthetic Compounds (1-TDPPO) Mixed Prop-2-en-1-one with Difluoro Phenyl. Sensors 2017, 17, 803 .
AMA StyleChanghyun Roh, Jaewoong Lee, Mayank Kinger, Chankyu Kang. In Vitro Studies on a Microfluidic Sensor with Embedded Obstacles Using New Antibacterial Synthetic Compounds (1-TDPPO) Mixed Prop-2-en-1-one with Difluoro Phenyl. Sensors. 2017; 17 (4):803.
Chicago/Turabian StyleChanghyun Roh; Jaewoong Lee; Mayank Kinger; Chankyu Kang. 2017. "In Vitro Studies on a Microfluidic Sensor with Embedded Obstacles Using New Antibacterial Synthetic Compounds (1-TDPPO) Mixed Prop-2-en-1-one with Difluoro Phenyl." Sensors 17, no. 4: 803.
Escherichia coli (E. coli) was used to activate hydrolysis reaction along with biodegradation in natural and synthetic fibers to identify possibilities as alternative substitutes for textile wastes using chemical solutions and enzymes. To confirm the reaction between the bacterial infections of E. coli and the excessively abundant interstitial spaces of the fibers, various types of natural and synthetic fibers such as cotton, wool, polyethylene terephalate (PET), polyadmide (PA), polyethylene (PE), and polypropylene (PP) were used to confirm the physico-chemical reactions. Tensile strength analysis, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and contact angle analysis were used to determine the physico-chemical property changes of the fiber by the bacteria. When biofilm was formed on the fiber surface, various physical changes such as the following were observed: (i) in the analysis of tensile strength, all except PA and PP were decreased and a decrease in cotton fibers was noticeable (ii) depending on the type of fibers, the degree of roughness was different, but generally the surface became rough. In this study, the change of roughness was the most severe on the cotton fiber surface and the change of PET and PA fiber was relatively small. It was found that the intensity peak of oxygen was increased, except for the in cases of PA and PP, through the change of chemical properties by XPS analysis. Changes in topographical properties on the surface through contact angle analysis were stronger in hydrophilic properties, and in the case of cotton, completely hydrophilic surfaces were formed. Through this study, PA and PP fibers, which are Olefin fibers, were theoretically free of physicochemical and topographical changes since there were no functional groups that could trigger the hydrolysis reaction.
Chankyu Kang; Sam Soo Kim; Soo Jung Kim; Jae Woong Lee. The Significant Influence of Bacterial Reaction on Physico-Chemical Property Changes of Biodegradable Natural and Synthetic Polymers Using Escherichia coli. Polymers 2017, 9, 121 .
AMA StyleChankyu Kang, Sam Soo Kim, Soo Jung Kim, Jae Woong Lee. The Significant Influence of Bacterial Reaction on Physico-Chemical Property Changes of Biodegradable Natural and Synthetic Polymers Using Escherichia coli. Polymers. 2017; 9 (4):121.
Chicago/Turabian StyleChankyu Kang; Sam Soo Kim; Soo Jung Kim; Jae Woong Lee. 2017. "The Significant Influence of Bacterial Reaction on Physico-Chemical Property Changes of Biodegradable Natural and Synthetic Polymers Using Escherichia coli." Polymers 9, no. 4: 121.
Deformable polydimethylsiloxane (PDMS) microfluidic devices embedded with three differently-shaped obstacles (hexagon, square, and triangle) were used to examine the significant challenge to classical fluid dynamics. The significant factors in determining a quasi-steady state value of flow velocity (v)QS and pressure drop per unit length (∆P/∆x)QS were dependent on the characteristic of embedded microstructures as well as the applied flow rates. The deviation from the theoretical considerations due to PDMS bulging investigated by the friction constant and the normalized friction factor revealed that the largest PDMS bulging observed in hexagonal obstacles had the smallest (∆P/∆x)QS ratios, whereas triangle obstacles exhibited the smallest PDMS bulging, but recorded the largest (∆P/∆x)QS ratios. However, the influence of (v)QS ratio on microstructures was not very significant in this study. The results were close to the predicted values even though some discrepancy may be due to the relatively mean bulging and experimental uncertainty. The influence of deformable PDMS microfluidic channels with various shapes of embedded microstructures was compared with the rigid microchannels. The significant deviation from the classical relation (i.e., f~1/Re) was also observed in hexagonal obstacles and strongly dependent on the channel geometry, the degree of PDMS deformation, and the shapes of the embedded microstructures.
Changhyun Roh; Jaewoong Lee; Chankyu Kang. Physical Properties of PDMS (Polydimethylsiloxane) Microfluidic Devices on Fluid Behaviors: Various Diameters and Shapes of Periodically-Embedded Microstructures. Materials 2016, 9, 836 .
AMA StyleChanghyun Roh, Jaewoong Lee, Chankyu Kang. Physical Properties of PDMS (Polydimethylsiloxane) Microfluidic Devices on Fluid Behaviors: Various Diameters and Shapes of Periodically-Embedded Microstructures. Materials. 2016; 9 (10):836.
Chicago/Turabian StyleChanghyun Roh; Jaewoong Lee; Chankyu Kang. 2016. "Physical Properties of PDMS (Polydimethylsiloxane) Microfluidic Devices on Fluid Behaviors: Various Diameters and Shapes of Periodically-Embedded Microstructures." Materials 9, no. 10: 836.