通过自手性和外消旋酪氨酸衍生的异氰酸酯-酚的自聚加成反应合成了旋光性聚氨酯(LPU和DPU)和外消旋聚氨酯(RPU)。所有聚合物均通过FT-IR表征1此外,还对1 H NMR,GPC,UV-Vis光谱,圆二色性(CD)光谱,TGA和X射线衍射(XRD)以及红外发射率值进行了研究。LPU和DPU是两个对映体,与具有随机盘绕分子链的RPU相比,它们具有螺旋构型和更高的氢键结合度。LPU和DPU的结晶度和热分解温度高于RPU,这是由于二级结构更为规则,有利于形成大量链间氢键。因此,LPU和DPU的红外发射率值较低(8–14μm),分别降至0.611和0.625。
Correlation between the secondary structure and hydrogen bonding in optically active polyurethane and its effect on infrared emissivity
作者:Yong Yang、Yuming Zhou、Jianhua Ge、Xiaoming Yang
DOI:10.1016/j.reactfunctpolym.2012.05.006
日期:2012.9
Abstract 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 opticalactivities 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