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( Se-ra Shin ),( Dai-soo Lee ),( Hyoung-joo Kim ),( Won-bae Park ),( You-seok Kim ) 한국폐기물자원순환학회(구 한국폐기물학회) 2019 ISSE 초록집 Vol.2019 No.-
The rigid polyurethane (PU) insulation foam scraps generated from the end-of-life refrigerators in the recycling centers of Ewastes amount to 20,000 tons per year in Korea. Recycling of these scraps have been studied due to the evolution of hydrogen cyanide and carbon monoxide, being highly toxic and corrosive in the combustion process, when the PU foam scraps are incinerated. In this study, we have developed a technique to chemically treat the scraps of the rigid PU foams to produce a recycled polyol and then to produce rigid PU foams. The processes of this chemical recycling technology are as follows: A liquefaction process by depolymerization via the glycolysis of the PU foam scraps; a filtration process for separating foreign substances; an addition process of the propylrnr oxide to the depolymerized products to get the recycled polyol. The recycled polyol obtained therefrom includes significant amount of aromatic moieties in comparison with virgin polyol generally. Therefore, when used in the production of rigid polyurethane foams for heat insulation again, the PU foams have excellent flame retardancy, low thermal conductivity, and high heat insulation performance. This study confirms that the results obtained from the beaker scale experiments are also available in pilot plant scale. Commercial production of the recycled polyol allows the construction of resources circulation systems for the PU foam scraps from E-wastes.
냉장고 단열재 스크랩 재활용 재생 폴리올 이용 난연성 경질 폴리우레탄 폼 제조 기술
신세라 ( Se-ra Shin ),이대수 ( Dai-soo Lee ),김형주 ( Hyoung-joo Kim ),박원배 ( Won-bae Park ),김유석 ( You-seok Kim ) 한국폐기물자원순환학회(구 한국폐기물학회) 2018 한국폐기물자원순환학회 춘계학술발표논문집 Vol.2018 No.-
사용이 끝난 냉장고를 회수하여 리싸이클링 센터에서 재활용하는 공정에서 단열재로 사용한 경질 폴리우레탄 폼 스크랩 발생량은 우리나라의 경우 연간 2만톤에 달하고 있다. 이러한 단열재 스크랩은 소각하는 경우 연소 과정에서 독성과 부식성이 강한 시안화수소 및 일산화탄소 발생이 문제되어 다양한 재활용 방안이 검토되고 있다. 본 연구에서는 경질 폴리우레탄 폼 냉장고 단열재 스크랩을 화학적으로 처리하고 재생 폴리올을 제조하여 다시 경질 폴리우레탄 폼을 제조하는 기술을 개발하였다. 이러한 화학적 재활용 기술의 공정들은 아래 그림에 나타낸 바와 같이, 경질 폴리우레탄 폼 해중합으로 저분자량화하는 액상화 공정, 이물질들을 분리하는 여과공정, 얻어진 화학 원료의 부가반응 공정 등을 포함한다. 여기서 얻어지는 재생 폴리올들은 방향족 구조 화합물 함량이 일반적으로 높은 특징을 가지게 된다. 따라서 다시 단열재용 등 경질 폴리우레탄 폼 제조에 사용하는 경우, 폼들은 난연성이 우수하고 열전도도가 낮아져 단열성능이 우수한 장점을 보임을 확인하였다. 본 연구는 실험실적 연구 단계에서 얻어진 결과가 실증 규모 파일롯 공장에서도 가능함을 확인하였다. 그리고 경제성도 무리가 없어 상업적 생산이 가능하게 되어, 소각 처리되던 폐기물을 단열제품 제조에 재사용하는 자원 순환 시스템 구축이 가능하였다.
Shin, Se‐,Ra,Kim, Han‐,Na,Liang, Jing‐,Yu,Lee, Sang‐,Hyub,Lee, Dai‐,Soo John Wiley Sons, Inc. 2019 Journal of applied polymer science Vol.136 No.35
<P><B>ABSTRACT</B></P><P>The preparation and characteristics of rigid polyurethane foams (RPUFs) based on recycled polyol obtained by glycolysis of waste RPUF scraps from end‐of‐life refrigerators were investigated. To deactivate the amine adducts derived from isocyanates, the recycled product obtained after depolymerization was chemically modified via addition polymerization of propylene oxide. Two kinds of recycled polyols with different hydroxyl values and viscosity were blended with conventional virgin polyether polyol to prepare the RPUFs. The effects of the recycled polyols on the physical properties of RPUFs such as cell structures, compressive strength, thermal conductivity, and limiting oxygen index were discussed. It was found that the RPUFs from recycled polyols showed superior compressive strength, thermal insulation property, and self‐extinguishing property compared with conventional control foam. The results of this study reveal that the recycled polyols could be used as feedstock for RPUFs with superior performance. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. <B>2019</B>, <I>136</I>, 47916.</P>
Shin, Jae Man,Kim, Minsoo P.,Yang, Hyunseung,Ku, Kang Hee,Jang, Se Gyu,Youm, Kyung Ho,Yi, Gi-Ra,Kim, Bumjoon J. American Chemical Society 2015 Chemistry of materials Vol.27 No.18
<P>Monodisperse colloidal particles of polystyrene-<I>b</I>-polybutadiene (PS-<I>b</I>-PB) block copolymers (BCPs) were successfully prepared, in which uniform emulsions containing BCPs were first generated by cross-flow membrane emulsification using tubular Shirasu porous glass (SPG) membrane, and then unique internal nanostructures were developed by controlled evaporation of solvent inside emulsion. The diameter of those BCP particles could be controlled from 200 nm to 5 μm by tuning the pore diameter of the membrane. With symmetric BCPs, onion-like nanostructures inside particles were formed. Coiled cylinders in the BCP particles were also developed by adding homopolymers, in which the assembled BCP structure is strongly dependent on the particle size, demonstrating the importance of our membrane method in generating monodisperse BCP particles. Further investigation of process parameters showed that for a given pore diameter, the operation pressure (<I>P</I>) and surfactant concentration were critical parameters for narrow size distribution of the particles. Uniform emulsions were produced when the ratio of the operation pressure to the critical pressure (P/Pc) was less than 4.33. In addition, uniformly sized, hierarchically structured particles of BCPs and nanoparticles (NPs) were produced, in which oleylamine-coated, 3 nm sized Au NPs were incorporated selectively into the PB domains inside the particles.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2015/cmatex.2015.27.issue-18/acs.chemmater.5b02020/production/images/medium/cm-2015-02020c_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm5b02020'>ACS Electronic Supporting Info</A></P>
모 조선업체 아크 용접 작업자의 공기중 6가 크롬 및 니켈 노출에 관한 연구
신용철,강성규,오세민,이나루,문영한,이광용,이기라 한국산업위생학회 1998 한국산업보건학회지 Vol.8 No.2
The aim of this study was to evaluate welders' exposure to hexavalent chromium (Cr(VI)) and nickel (Ni) during welding operations in a Korean shipyard. The airborne Cr(VI) and Ni concentrations were measured during metal inert gas (MIG) welding on mild and stainless steel, and manual metal arc (MMA) welding on mild steel. The geometric mean (GM) of Cr(VI) concentrations inside the welding helmet during MIG welding on mild steel were 0.0018 ㎎/㎥ inside a ship section, and 0.0015-0.0026 ㎎/㎥ at the welding shops. All of the personal breathing zone air samples were below the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV^ⓡ) of 0.01 ㎎/㎥. Conversely, eighty-eight percent(21 of 24) of the personal breathing zone air samples exceeded the National Institute for Occupational Safety and Health (NIOSH) recommended exposure limit of 0.001 ㎎/㎥. Ni was not detected on 20 of 23 air samples collected during MIG welding on mild steel. The three Ni samples above the limit of detection ranged from 0.015 to 0.044 ㎎/㎥. The GM of Cr(VI) concentrations during MMA welding on mild steel were 0.0013 ㎎/㎥, but Ni was not detected in the air samples during this operation. It is assumed that the airborne Cr(VI) and Ni during mild steel welding were derived from the base metals which contained about 0.03% Cr and 0.03% Ni. The GM of airborne total Cr, Cr(V1) and Ni concentrations during MIG welding on stainless steel were 4.02, 0.13 and 0.86 ㎎/㎥, respectively, and the levels of Cr(VI) and Ni were above the ACGIH-TLV^ⓡ Cr(VI) comprised about 35.5% of the total chromium(Cr) from MIG welding on mild steel, and about 8.4% of total Cr from MIG welding on stainless steel. The ratios of Cr(VI) to total Cr were significantly different among welding shops. It was concluded that welders were exposed to high levels of Cr(VI) and Ni during welding on stainless steel, and were exposed to low levels of Cr(VI) even during welding on mild steel.