1322097-64-2Relevant academic research and scientific papers
Correlation between the secondary structure and hydrogen bonding in optically active polyurethane and its effect on infrared emissivity
Yang, Yong,Zhou, Yuming,Ge, Jianhua,Yang, Xiaoming
experimental part, p. 574 - 579 (2012/10/07)
Optically active polyurethanes (PUs) with different specific rotations were synthesized using a hydrogen transfer addition polymerization procedure with isocyanate-phenols of varying enantiomeric excess. The optical activities of the PUs were enhanced with an increase in the enantiomeric excess of the monomers. A helical secondary structure in the PUs with a more compact arrangement of the macromolecular backbones facilitated interchain hydrogen bonding, and the infrared emissivity of the corresponding polymers decreased. The results indicated that the level of order and number of hydrogen bonds in the macromolecule played significant roles in controlling the infrared emissivity.
Synthesis, characterization and infrared emissivity property of optically active polyurethane derived from tyrosine
Yang, Yong,Zhou, Yuming,Ge, Jianhua,Wang, Yongjuan,Chen, Xinglan
experimental part, p. 3745 - 3751 (2012/03/13)
Optically active polyurethanes (LPU and DPU) and racemic polyurethane (RPU) were synthesized by the self-polyaddition of the isocyanate-phenols which derived from the chiral and racemic tyrosine. All of the polymers were characterized by FT-IR, 1H NMR, GPC, UV-Vis spectroscopy, circular dichroism (CD) spectroscopy, TGA and X-ray diffraction (XRD), and the infrared emissivity values were investigated in addition. LPU and DPU were two enantimorphs, they possessed helical configurations and higher degree of hydrogen bondings compared to the RPU which presented random coiled molecular chain. The crystallinity and thermal decomposition temperature of LPU and DPU were higher than that of the RPU due to the more regular secondary structure which facilitate the formation of a large number of inter-chain hydrogen bonds. Consequently, the LPU and DPU exhibited lower infrared emissivity values (8-14 μm), which came down to 0.611 and 0.625.
