Papers by Author: Byung Won Kang

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Authors: Byung Won Kang, T. Yoshida, Jong Baek Lee, S.J. Jeon, H.D. Choi
Abstract: In order to elucidate the relationship between the structure and biological activity such as anti-HIV and blood anticoagulant activity, sulfonated polysaccharides and amino-polysaccharides having pentofuranosidic structures were synthesized. These sulfonated polysaccharides had potent anti-HIV activity in spite of low molecular weights, and which was dependent on the degree of sulfonation. For the blood anticoagulant activity, the conformation of polymer backbone and sulfamide group plays an important role on the interactions with the blood anticoagulant factor.
721
Authors: Jong Baek Lee, Byung Won Kang
Abstract: A new type of thermotropic main-chain liquid crystalline polyurethanes containing biphenyl units was synthesized by polyaddition reaction of diisocyanates such as 2,6-tolylene diisocyanate, 2,5-tolylene diisocyanate, 2,4-tolylene diisocyanate, and 1,4-phenylene diisocyanate, with 4,4′-Bis(8-hydroxyoctoxy)biphenyl (BP8). The structure of the monomer and the corresponding polymers were confirmed using FT-IR and 1H-NMR spectroscopic methods. BP8 exhibited a smectic type mesophase, however, nematic phases were found for all synthesized liquid crystalline polyurethanes except for 1,4-phenylene diisocyanate/BP8 based polyurethane. For example, polyurethane 2,5-TDI/BP8 exhibited monotropic liquid crystallinity in the temperature ranging from 172 to 160 °C on the cooling stage. Properties of these polyurethanes were studied by differential scanning calorimetry (DSC), and optical polarizing microscopy. The FT-IR study indicated that the hydrogen bonding among urethane linkages attributed to the mesomorphism.
729
Authors: Jong Baek Lee, Kwang Hyun Lee, Byung Chul Kang, Byung Won Kang, Sang Ll Lee, Jin Kyung Lee
Abstract: A new type of thermotropic main-chain liquid crystalline polyurethanes containing biphenyl units was synthesized by polyaddition reaction of diisocyanates such as 2,6-tolylene diisocyanate, 2,5-tolylene diisocyanate, 2,4-tolylene diisocyanate, and 1,4-phenylene diisocyanate, with 4,4′-Bis(11-hydroxyundeyloxy)biphenyl (BP11). The structure of the monomer and the corresponding polymers were confirmed FT-IR and 1H NMR spectroscopic methods. BP11 exhibited a smectic type mesophase, however, nematic phase was found for all synthesized liquid crystalline polyurethanes except for 1,4-phenylene diisocyanate/BP11 based polyurethane. For example, polyurethane 2,5-TDI/BP11 exhibited monotropic liquid crystallinity in the temperature ranges from 173 to 156 °C on the cooling stage.
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