Print: | ISSN 0304-128X |
Online: | ISSN 2233-9558 |
Korean Chemical Engineering Research,
Vol.48, No.5, 615-620, 2010 4,4'-Bis(3-hydroxypropoxy)Biphenyl와 Diisocyanate에 의한 열방성 액정폴리우레탄 합성
Thermotropic Polyurethanes Prepared from Diisocyanates and 4,4'-Bis(3-hydroxypropoxy)Biphenyl Containing Mesogenic Unit
본 실험은 다섯 종류의 새로운 형태의 액정성 폴리우레탄을 4,4'-Bis(3-hydroxypropoxy)biphenyl (BP3)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 BP3은 스멕틱상을 형성하였으며 HDI/BP3을 제외한 나머지 폴리우레탄에서는 모두 단방성 액정성을 나타내었다. 그러나 메틸 치환기를 가지고 있지 않는 1,4-PDI/BP3에서는 DSC 및 편광현미경에서도 액정상을 전혀 관찰할 수 없었다. 합성된 화합물의 구조는 FTIR 및 1H-NMR에 의해 확인하였으며, 그들의 열적 상전이온도 및 안정성들은 DSC, 편광현미경 및 x-선 회절에 의해 조사하였다.
In this study, five series of novel polyurethanes was 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), hexamethylene diisocyanate(HDI) with 4,4'-Bis(3-hydroxypropoxy)biphenyl (BP3), 4,4'-bis(3-hydroxypropoxy)biphenyl exhibited a smectic type mesophase. Monotropic mesophase was found for all synthesized liquid crystalline polyurethanes except HDI/BP3. In contrast, 1,4-PDI/BP3 without a methyl substituent in the phenylene unit exhibited no explicit mesomorphic behavior, which was confirmed by DSC and polarizing microscopy experiments. 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.
Keywords:
4,4'-Bis(3-hydroxypropoxy)biphenyl (BP3); Liquid Crystalline Polyurethane; POM; Smectic; Mesophase
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