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℃.

Reaction of Gas-Phase Bromine Atom with Chemisorbed Hydrogen Atoms on a Silicon(100)-(2${\times}$1) Surface

이종백,장경순,문경환,김유항,Lee, Jong Baek,Jang, Gyeong Sun,Mun, Gyeong Hwan,Kim, Yu Hang Korean Chemical Society 2001 Bulletin of the Korean Chemical Society Vol.22 No.8

The reaction of gas-phase atomic bromine with highly covered chemisorbed hydrogen atoms on a silicon surface is studied by use of the classical trajectory approach. It is found that the major reaction is the formation of HBr(g), and it proceeds th rough two modes, that is, direct Eley-Rideal and hot-atom mechanism. The HBr formation reaction takes place on a picosecond time scale with most of the reaction exothermicity depositing in the product vibration and translation. The adsorption of Br(g) on the surface is the second most efficient reaction pathway. The total reaction cross sections are $2.53{\AA}2$ for the HBr formation and $2.32{\AA}2$ for the adsorption of Br(g) at gas temperature 1500 K and surface temperature 300 K.

NFS 게이트웨이를 이용한 하둡 분산 파일 시스템의 성능 연구

이종백(Jongbaeg Lee),박종혁(Jong-Hyeok Park),이재훈(Jaehun Lee),박재호(Jaeho Park),이상원(Sang-won Lee) 한국정보과학회 2017 한국정보과학회 학술발표논문집 Vol.2017 No.06

Ester기를 갖는 새로운 주쇄형 액정 coumarin 화합물의 합성 및 특성분석

이종백 ( Jong Back Lee ),강병철 ( Byung Chul Kang ),이강춘 ( Gang Choon Lee ),이동진 ( Dong Jin Lee ),( Kihara Hideyuki ) 한국고무학회 2009 엘라스토머 및 콤포지트 Vol.44 No.4

Benzyl 4-Hydroxybenzoate와 1,6-Dibromohexane을 반응시켜 4-(6-bromohexyloxy)benzoic acid를 합성하였다. 이것을 하이드로퀴논과 반응시켜 브롬 그룹을 갖는 새로운 mesogenic ester를 합성하였다. Mesogenic ester를 자외선에 민감한 coumarin과 반응시켜 새로운 형태의 광응답성 coumarin 화합물을 합성 하였다. 합성된 화합물의 구조는 FT-IR 및 1H-NMR에 의해 확인 하였으며, 그들의 열적 상전이온도 및 안정성들은 DSC, 편광현미경 및 X-선 회절에 의해 조사 하였다. 한편 합성된 새로운 화합물은 광학 편광 현미경 관찰에 의해 스멕틱 및 네마틱 구조를 갖는 쌍방성 액정성을 보였다. 4-(6-bromohexyloxy)benzoic acid was synthesized from benzyl 4-Hydroxybenzoate and 1,6-dibromohexane. It was reacted with hydroquinone to obtain a new mesogenic ester having an bromine group. One kind of new photoresponsive coumarin compound was prepared by the reaction of mesogenic ester with coumarin sensitive to the ultraviolet. Structures of the compound were identified by FT-IR and 1H-NMR spectroscopies. Their phase transition temperatures and thermal stability were also investigated by differential scanning calorimetry (DSC), polarized optical microscopy (POM) and x-ray diffraction analysis. From optical polarizing microscopy, the prepared compound was found to show enantiotropic liquid crystallinity with smectic and nematic textures.

액정폴리우레탄의 합성 및 특성

이종백 ( Jong Back Lee ),이광현 ( Kwang Hyun Lee ),강병철 ( Byung Chul Kang ),이동진 ( Dong Jin Lee ) 한국고무학회 2009 엘라스토머 및 콤포지트 Vol.44 No.3

4종류의 새로운 형태의 열방성 액정폴리우레탄을 4,4`-Bis(5-hydroxypentoxy)biphenyl (BP5)와 2,6-tolylene diisocyanate (2,6-TDI), 2,5-tolylene diisocyanate (2,5-TDI), 및 2,4-tolylene diisocyanate(2,4-TDI), 1,4-phenylene diisocyanate (1,4-PDI) 의 중부가 반응에 의해 합성하였다. 단량체 BP5은 스멕틱상을 형성하였으며 1,4-PDI/BP5을 제외한 나머지 폴리우레탄에서는 모두 액정성을 나타내었다. 생성된 폴리우레탄의 구조는 FT-IR과 1H NMR 스펙트럼으로 확인하였고 열적 성질은 DSC와 편광현미경으로 관찰하였다. Four series of novel liquid crystalline polyurethanes were synthesized by the polyaddition reaction of diisocyanates such as 2,6-tolylene diisocyanate (2,6-TDI), 2,5-tolylene diisocyanate (2,5-TDI), 2,4-tolylene diisocyanate (2,4-TDI), and 1,4-phenylene diisocyanate (1,4-PDI) with 4,4`-bis(5-hydroxypentoxy)biphenyl (BP5). 4,4`-bis(5-hydroxypentoxy)biphenyl exhibited a smectic type mesophase. Mesophase was found for all synthesized liquid crystalline polyurethanes except 1,4-PDI/BP5. The structures and the thermal properties of polyurethanes were studied by using FT-IR and 1H NMR spectroscopy, DSC measurements and a polarizing microscope equipped with a heating stage.

Coumarin이 함유된 액정고분자의 광중합

이종백 ( Jong Back Lee ),이광현 ( Kwang Hyun Lee ),강병철 ( Byung Chul Kang ) 한국고무학회 2010 엘라스토머 및 콤포지트 Vol.45 No.4

Coumarin기가 포함된 액정성을 가진 단량체를 액정 상태에서 UV 조사에 의해 중합하였다. Cycloaddition 반응에 의해 coumarin 액정 단량체는 이량체로 전환되었으며, 광이량화 반응 후에도 액정성이 유지되었다. 그리고 이러한 이량체는 단량체의 액정범위 보다 넓은 영역에서 액정성을 나타내었다. 화합물의 구조는 FT IR 및 1H NMR에 의해 확인하였으며, 그들의 열적 상전이온도 및 열안정성들은 DSC, GPC 및 편광현미경에 의해 조사하였다. 광중합에 의해 생성된 고분자 생성물은 광학 편광 현미경 관찰에 의해 스멕틱 및 네마틱 조직을 갖는 쌍방성 액정성을 보였다. Liquid-crystalline (LC) monomer, which was functionalized with a coumarin group on their extremity, was synthesized by UV light irradiation in their LC phases. LC monomer was converted into the dimers by the cycloaddition reaction of the coumarin group, and the LC phases were maintained after photodimerization reaction. The dimers showed LC phases in the wider temperature range than those of the corresponding monomer. Structures of the compound were identified by FT IR and 1H NMR spectroscopies. Their phase transition temperatures and thermal stability were also investigated by differential scanning calorimetry (DSC), gel permeating chromatography (GPC) and polarized optical microscopy (POM). From optical polarizing microscopy, the prepared polymer shows enantiotropic liquid crystallinity with smectic and nematic textures.

새로운 형태의 액정플리우레탄의 합성과 성질

이종백 ( Jong Back Lee ),강병철 ( Byung Chul Kang ),유일 ( Il Yu ) 한국공업화학회 2002 공업화학 Vol.13 No.8

다섯 종류의 새로운 형태의 액정성 폴리우레탄을 4,4`-bis(7-hydroxyheptoxy)biphenyl (BP7)와 2,6-tolylene diisocyanate (2,6-TDI), 2,5-tolylene diisocyanate (2,5-TDI), 2,4-tolylene diisocyanate (2,4-TDI), 1,4-phenylene diisocyanate (1,4-PDI) 및 hexamethylene diisocyanate (HDI)의 중부가 반응에 의해 합성하였다. 단량체 BP7은 스멕틱상을 형성하였으며 1.4PDI/BP7을 제외한 나머지 폴리우레탄에서는 모두 액정성을 나타내었다. 생성된 폴리우레탄의 구조는 IR과 ^1H NMR 스펙트럼에 의해 확인하였고 열적 성질은 DSC와 편광현미경으로 관찰하였다. Five series of novel polyurethanes were synthesized by the polyaddition reaction of diisocyanates: 2,6-tolylene diisocyanate (2,6-TDI), 2,5-tolylene diisocyanate (2,5-TDI), 2,4-tolylene diisocyanate (2,4-TDI), and 1,4-phenylene diisocyanate (1,4-PDI), hexamethylene diisocyanate (HDI) with 4,4`-Bis(7-hydroxyheptoxy) biphenyl (BP7). 4,4`-bis(7-hydroxyheptoxy) biphenyl exhibited a smectic type mesophase. All synthesized liquid crystalline polyurethanes except 1,4-PDI/BP7 exhibit liquid crystalline behavior. The structures and the thermal properties of polyurethanes were studied by using FT-IR and ^1H NMR spectroscopy, DSC measurements and a polarizing microscope equipped with a heating stage.

液晶性 Polyurethane의 合成과 物性에 關한 硏究

이종백(Jong Back Lee),송진철(Jin Cherl Song),최대웅(Dae Woong Choi) 한국염색가공학회 1996 韓國染色加工學會誌 Vol.8 No.1

비페닐렌 메소겐단위를 포함한 4,4`-bis(ω-hydroxyalkoxy)biphenyl 의 합성 및 열적성질

이종백 ( Jong Baek Lee ) 한국공업화학회 2002 공업화학 Vol.13 No.7

화합물 4,4`-bis(ω-hydroxyalkoxy)biphenyls (BPm; m=3, 4, 5, 6, 7, 8, 9, 10, 11, 12)은 4,4`-dihydroxybiphenyl와 ω-halogenated alkanols를 반응시켜 합성하였다. IR 및 ^1H NMR 스펙트럼을 사용하여 합성된 BPm의 구조를 분석하였다. 이들의 열적 및 액정특성을 관찰하기 위해서 DSC 및 편광현미경을 사용한 결과, BPm은 모두 일정한 온도 영역에서 스멕틱 상의 액정성을 나타내었다. 또한 이러한 액정 화합물은 전형적인 짝수-홀수의 효과를 나타내었다. A series of 4,4`-bis(ω-hydroxyalkoxy)biphenyls (BPm; m=3, 4, 5, 6, 7, 8, 9, 10, 11, 12) was synthesized by the reaction of 4,4-dihydroxybiphenyl with ω-halogenated alkanols. The chemical structures of BPm were determined by lnfrared and ^1H NMR spectra. All these compounds exhibited a smectic liquid crystalline phase in a certain temperature range, which was determined by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). The liquid crystalline compounds also showed the typical even-odd effect.

방향족 고리를 갖는 액정폴리우레탄의 합성 및 특성

이종백 ( Jong Baek Lee ) 한국고무학회 2013 엘라스토머 및 콤포지트 Vol.48 No.2

메소겐(Mesogen) 단위가 포함되어 있지 않는 para- 형태의 1,4-phenylene diisocyanate (1,4-PDI)와 2,6-bis(ω-hydroxypentoxy)naphthalene (BHN5) 또는 1,4-bis(ω-hydroxypentoxy)benzene (BHB5)을 단일과 공중합폴리우레탄을 부가중합에 의해 합성하였다. 모든 공중합폴리우레탄에서는 전단변형의 측정에서 단방성액정상을 나타내었다. 예를 들면, 고유점도가 [∩]=0.32 dL/g인 폴리우레탄 Poly(50/50, mol%)은 223℃∼211℃에서 냉각 시 액정성을 나타내었다. 그러나 두 개의 단일폴리우레탄에서는 DSC (Differental Scanning calorimeter) 측정 및 편광현미경 관찰에서도 액정상을 전혀 관찰 할 수 없었다. 합성된 폴리우레탄의 액정성은 시차주사열량분석기, 편광현미경과 X-ray에 의해 확인하였다. Polyurethanes containing no mesogenic unit were prepared by polyaddition reaction of homo- and copolyurethanes based on para-type 1,4-phenylene diisocyanate (1,4-PDI), 2,6-bis(ω-hydroxypentoxy)naphthalene (BHN5) with 1,4-bis(ω-hydroxypentoxy)benzene (BHB5). All copolyurethanes showed monotropic liquid crystallinity, when measurements were performed under shearing. For example, a polyurethane Poly(50/50, mol%) with [∩]=0.32 dL/g exhibited liquid crystallinity in the temperature range from 223℃ to 211℃ in the cooling stage. In contrast, two homopolyurethanes exhibited no explicit mesomorphic behavior, which was observed by DSC (Differental Scanning calorimeter) and measurement and polarized microscopic observation. The mesomorphic behavior of synthesized polyurethane was identified and characterized by differential scanning calorimetry, polarized optical microscope and X-ray.