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Mesogen 을 포함하지 않은 액정 polyurethane 의 합성과 열적성질에 관한 연구
이종백,최대웅 ( Jong Back Lee,Dae Woong Choi ) 한국공업화학회 1997 공업화학 Vol.8 No.2
액정 polyurethane은 DMF 용매중 1,4-bis(6-hydroxyhexoxy)benzene (BHB6)과 2,5-tolylene diisocyanate (2,5-TDI)를 중부가 반응에 의해서 합성하였다. 고유점도는 0.26, 0.42 ㎗/g였다. 생성된 polyurethane의 열적성질 및 구조확인은 DSC, 편광현미경, X-ray회절 그리고 ¹H-NMR 및 FT-IR에 의해 확인하였다. 특히 분자량이 서로 다른 polyurethane 2,5-TDI/BHB6의 열적성질 및 물성에 대해서 비교 검토하였다. 고유점도가 [η]=0.26인 polyurethane 2,5-TDI/BHB6는 monotropic 액정성을 나타내었다. 이러한 것은 구조적으로는 mesogen을 포함하고 있지 않다. 예를 들면 LCPU-L(저분자량)은 T_(I.LC)(등방성액체상전이점-액정) 및 T_(LC-k)(액정-결정)은 122℃부터 89℃까지 관찰되었다. Liquid crystalline polyurethanes were prepared from 1,4-bis(6-hydroxyhexoxy)benzene (BHB6) and 2,5-tolylene diisocyanate (2,5-TDI) solution polymerization in dimethylformamide produced intrinsic viscosities in the range 0.26 and 0.42 ㎗/g. The polyurethanes were investigated by DSC, Polarizing microscopy, X-ray, ¹H-NMR and IR spectroscopy. Polyurethanes of two different molecular weights were studied in detail and these will be referred to as low molecular weight and high molecular weight. Polyurethane 2,5-TDI/BHB6 with [η]=0.26 ㎗/g prepared from BHB6 and 2,5-TDI, exhibited monotropic liquid crystallinity, although these polyurethanes contained no mesogenic core unit. For example, LCPU-L(low molecular weight) exhibited T_(I.LC) of 122 ℃ and T_(LC-k) of 89℃.
아크릴 폐수의 전처리공정에 따른 UF(tubular)/RO(spiral wound) 공정의 성능변화
이광현 ( Kwang Hyun Lee ),한성범 ( Sung Bum Han ),최대웅 ( Dae Woong Choi ) 한국물환경학회 2002 한국물환경학회지 Vol.18 No.4
The efficiency variation of UF(tubular)/RO(spiral wound) process using acrylic wastewater treated by photo-catalyst pretreatment and coagulant-filter-neutralization pretreatment processes were discussed wit the variation of appled pressure and temperature. Ultrafiltration tubular module using acrylic wastewater treated by photo-catalyst pretreatment and coagulant-filter-neutralization pretreatment processes was shown that COD and T-N were not highly affected with the variation of appled pressure and temperature. It was shown that removal efficiency of COD and T-N was low. Removal efficiency of TDS and turbidity with ultrafiltration tubular module was better with the acrylic wastewater by photo-catalyst pretreatment than acrylic wastewater by coagulant-filter-neutralization pretreatment. T-N and TDS were shown high removal efficiency in reverse osmosis membrane process
최대웅 東義大學校産業技術開發硏究所 2008 産業技術硏究誌 Vol.22 No.-
The continuous extraction of cadmium ion from aqueous solution in a hollow fiber module was conducted using extractants of D2EHPA, Lix84, TOA and TBP, and the variation of extraction efficiency from mixed ion solution and mixed extractants was experimentally investigated. Comparison of the experimental outcome with a conventional solvent extraction and menbrane extraction leads to the following results. The continuous extraction improves the extraction efficiency and reduces solvent consumption and processing time. The mixed extractant systems is no significant effect. The menbrane extraction is more convenient than the conventional solvent extraction process, but the extraction efficiency is close. Other heavy metal ions do not affect the extraction of cadmium in quaternary mixed solution.
최대웅 東義大學校産業技術開發硏究所 2009 産業技術硏究誌 Vol.23 No.-
Comparison of the experiment outcome with the conventional solvent extraction process and the membrane extraction process lead to the following results. The continuous extraction process improves the extraction efficiency and solvent consumption and processing time. The coexisting elements give no significant effect on copper extract, while the mixed extractants of D2EPA-TOPO(TBP) systems reduce the extraction efficiency. The membrane extraction process is more convenient than the conventional solvent extraction process, but extraction efficiency is close.