• Title/Summary/Keyword: Low-volatile polymer

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Performance Evaluation of Organic-Inorganic Adhesives and Organic Adhesives for Polishing Tile Adhesion (폴리싱 타일 접착용 유·무기계 접착제와 유기계 접착제의 성능 평가)

  • Seo, Jong-Oh;Jeon, Jin-Ho;Park, Chang-Hwan;Cho, Sung-Hyun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.11a
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    • pp.211-212
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    • 2023
  • Polishing tiles among porcelain tiles are more durable and aesthetic than ceramic tiles, so their demand has recently increased. In particular, since polishing tiles have a very low absorption rate, organic adhesives with chemical bonds are mainly used. However, organic adhesives have low economic efficiency and some volatile organic compounds (TVOCs). Therefore purpose of this study was to evaluate the performance of polishing tile adhesion by developing organic-inorganic adhesives, which have chemical bonds and mechanical bonds. As a result, since the amorphous chain and chemical bonds of the polymer in the tile adhesives, both tensile and shear adhesion strength were satisfied with the KS L 1592, KS L 1593, and the rate of length change itself in the thermal cycling was lower than organic adhesives. So it is thought that it is possible to replace some organic adhesives.

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Development of Volatile Organic Compound Pretreatment Device for Removing Exhaust Gas from Display Manufacturing Process (Display 제조공정 배출가스 처리를 위한 휘발성 유기화합물 전처리 장치 개발)

  • Moon, Gi-Hak;Kim, Jae-Yong
    • Applied Chemistry for Engineering
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    • v.30 no.5
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    • pp.523-529
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    • 2019
  • In this study, we investigated the pretreatment technologies of volatile organic compounds (VOCs) which is a problem as the semiconductor and display industry develops recently. The conventional concentrator used in the direct combustion system, is easily contaminated by the exhaust gas in the manufacturing process of the display, resulting in the low treatment efficiency of generated VOCs. Physical/Chemical analyses of the exhaust gas showed high boiling point and viscosity in addition to a large amount of molecular weight alcohols and oil components. In this study, we tried to treat degrading materials by using the heat exchanger in a pretreatment facility and some materials degrading the concentrator were condensed more than 90%. In addition, it was also confirmed that an auxiliary device of the grease filter could remove the redispersion polymer oil from the heat exchanger.

Syntheses and Characterization of UV-curable Polyurethane Acrylates with Eco-friendly Polyols (친환경 폴리올을 이용한 광경화형 폴리우레탄 아크릴레이트의 합성)

  • Lee, Bong;Kim, Yeong Woo;Lee, Won-Ki
    • Journal of Adhesion and Interface
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    • v.20 no.4
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    • pp.140-145
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    • 2019
  • In view of environmental considerations, the control of carbon dioxide (CO2) and volatile organic compounds (VOCs) is one of important issues in the film and coating industries. Therefore, UV-curable system has been developed due to minimize emissions of VOCs and reduce CO2 emission due to low energy consumption from fast curing. Also, biodegradable polymers economically are attractive because of environmental and economic concerns associated with huge waste plastics. In this study, UV-curable polyurethane acrylates with different compositions of biodegradable polylactide (PLA) diol and poly(ethylene glycol) as diols were synthesized and curing reaction of their end-capped acrylates was performed by UV exposure. Tensile strength, elongation, and Tg of the UV-cured polyurethane acrylates increased with PLA diol content in the diol while their hydrophilicity and thermal stability increased with the PEG content. These results indicated a property of UV-cured polyurethane acrylates could be controlled by environment-friendly diols.

Fabrication of Block Copolymer Membranes via SNIPS Process (SNIPS 공정을 이용한 블록공중합체 분리막의 구조 형성에 관한 연구)

  • Woo, Sanghoon;Kim, Jinhee;Lee, Junghyun;Bang, Joona
    • Korean Chemical Engineering Research
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    • v.55 no.2
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    • pp.214-219
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    • 2017
  • In this work, we fabricated PS-b-P4VP block copolymer membranes from self-assembly and non-solvent induced phase separation (SNIPS), which combines the block copolymer self-assembly and conventional NIPS process. While previous studies mostly focused on the fabrication of well-defined structures, we systematically examined various processing parameters such as polymer concentration, solvent evaporation duration, solvent composition, and humidity, to optimized the membrane structures. As a result, the morphology of PS-b-P4VP membranes was optimized at a certain polymer concentration in solution and composition of volatile solvent at low humidity conditions, resulting in SNIPS separation membranes with well-defined nanopores on the surface, 75% of membrane porosity, and 18% of surface porosity.

Highly Sensitive Colorimetric Formaldehyde Gas Sensors using Nylon Sheet and Dye (나일론 시트와 염료를 이용한 고감도 색변환 포름알데히드 가스 센서)

  • Jung, Suenghwa;Cho, Yeong Beom;Kim, Yong Shin
    • Journal of Sensor Science and Technology
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    • v.26 no.6
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    • pp.420-426
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    • 2017
  • A colorimetric sensor was investigated to achieve a low-cost warning device for harmful gaseous formaldehyde (HCHO). The sensor is based on selective reactions between hydroxylamine sulfate and HCHO, leading to the production of sulfuric acid. The produced acid results in color-changing response through the acid-base reaction with dye molecules impregnated on a solid membrane substrate. For attaining this purpose, sensors were fabricated by drop-casting a dye solution prepared using different pH indicators on various commercially available polymer sheets, and their colorimetric responses were evaluated in terms of sensitivity and reliability. The colorimetric sensor using bromophenol blue (BPB) and nylon sheet was found to exhibit the best performance in HCHO detection. An initial bluish green of a sensor was changed to yellow when exposed to gaseous formaldehyde. The color change was recorded using an office scanner and further analyzed in term of RGB distance for quantifying sensor's response at different HCHO(g) concentrations. It exhibited a recognizable colorimetric response even at 50 ppb, being lower than WHO's standard of 80 ppb. In addition, the sensor was found to have quite good selectivity in HCHO detection under the presence of common volatile organic compounds such as ethanol, toluene, and hexane.

Manufacture of High Density Graphite Using Coal Tar Pitch (석탄계 피치를 이용한 고밀도 흑연 제조)

  • Cho, Kwang-Youn;Kim, Kyung-Ja;Riu, Doh-Hyung;Lim, Kwang-Hyun;Kim, Jung-Il;Shin, In-Cheol;Lim, Yun-Soo;Joo, Heyok-Jong
    • Journal of the Korean Ceramic Society
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    • v.43 no.12 s.295
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    • pp.839-845
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    • 2006
  • Graphite has hexagonal closed packing structure with two bonding characteristics; (1) van der waals bonding between c axis, and (2) covalent bonding in the a and b axis. The weak van der waals bonds cause self-lubricant property, and the strong covalent bonds cause excellent electric and thermal conductivity. Furthermore, graphite is chemically very inert because of the material composed of only carbon elements. Thus, graphite is very useful for mechanical sealing materials. However, Graphite have porous microstructure because starting materials of graphite produce many volatile during the manufacturing processes. This causes low density of graphite, which is unsuitable for the mechanical sealing materials. Thus, further impregnation process is generally needed to enhance the graphite density. In this work, high density graphite is prepared with the principle of densification when coke and pitch binder, prepared from thermal treatment of coal tar pitch, become dehydrogenation during graphitization or carbonization.

Behaviors of Pollutants and Microorganisms in an Anaerobic Digestion of Propionate Containing High Ammonia Nitrogen Level (고농도 암모니아성 질소를 함유한 프로피온산의 혐기성 분해시 오염물질 및 미생물 거동)

  • Lee, Chae-Young;Kim, Dae-Sung;Ahn, Won-Sik;Shin, Hang-Sik
    • Journal of the Korea Organic Resources Recycling Association
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    • v.14 no.3
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    • pp.126-137
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    • 2006
  • Behaviors of simple organic compound and granular sludge in an upflow anaerobic sludge blanket (UASB) reactor treating propionate at high ammonia nitrogen levels were investigated for 12 months. The UASB reactor achieved about 80% removal of chemical oxygen demand (COD) at ammonia nitrogen concentration up to 6000 mg-N/L. At higher concentration of ammonia nitrogen, the propionate in the effluent increased whereas the acetate was very low. At ammonia nitrogen concentration of 8000 mg-N/L, the volatile suspended solids (VSS) increased sharply due probably to the decrease of the content of extracellular polymer (ECP) although methane production was very low. The specific methanogenic activity (SMA) using formate, acetate, and propionate as substrate to granules decreased as ammonia nitrogen concentration increased. The ammonia nitrogen concentration $I^{50}$, causing 50% inhibition of SMA were 2666, 4778 and 5572 mg-N/L, respectively. The kinetic coefficients of ammonia inhibition using formate, acetate, and propionate as substrate were 3.279, 0.999 and 0.609, respectively. The SMA using formate was severely affected by ammonia nitrogen than those using acetate and propionate. This result indicated that the hydrogenotrophic methanogens was most affected by ammonia nitrogen. Granules were mainly composed of microcolonies of methanothrix-like bacteria resembling bamboo-shape, and several other microcolonies including propionate degrader with juxtapositioned syntrophic associations between the hydrogen-producing acetogens and hydrogen-consuming methanogens.

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Effect of PFO/Coal-tar Blending Ratio on Yield and Physical Properties of Pitch-based Activated Carbon (열분해유/콜타르 혼합비가 피치계 활성탄의 수율 및 물성에 미치는 영향)

  • Tae Ung Yoo;Sang Wan Seo;Ji Sun Im;Soo Hong Lee;Woo Jin Song;Seok Chang Kang
    • Applied Chemistry for Engineering
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    • v.35 no.2
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    • pp.107-114
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    • 2024
  • In order to produce high-yield pitch-based activated carbon, pitch was synthesized by blending pyrolysis fuel oil (PFO) and coal-tar. Pitch was synthesized by varying the amount of coal-tar from 0~20% compared to PFO and reacting at 380~420 ℃ for 3 h. The synthesized pitch had a softening point between 80 and 260 ℃, and yields ranged from 10 to 40%. At all synthesis temperatures, as the coal-tar blending ratio increased, the yield increased and the softening point decreased. After considering the selected pitches (softening points: 230~260 ℃), pitches containing coal-tar were more volatile at a low boiling point and had a higher residual carbon content. This is a difference in the composition of coal-tar and PFO, and it was con- firmed that coal-tar has a lot of aromatics and PFO has a lot of aliphatics. The selected pitch was heated to 950 ℃ in a tubular reactor and physically activated with steam for 1 hour. Activated carbon containing coal-tar showed higher yield and microporosity compared to only PFO. In this study, the effect of increasing activated carbon yield by blending pitch raw materials was confirmed, and the physical activation characteristics according to the coal-tar mixing ratio were examined.