一种新的侧链型液晶高分子的光谱研究

THE SPECTROSCOPIC STUDY OF A NOVEL SIDE CHAIN LIQUID CRYSTAL POLYMER

本工作使用FTIR、FT-RAMAN、~1H-NMR和^(13)C-NMR等方法,对一新型的侧链型液晶高分子聚-2,5-双(4-甲氧基苯甲酰氧基)苯乙烯的结构进行了表征,并对形成液晶态的分子间相互作用力作了讨论。实验结果表明,这种侧链型液晶高分子的相互作用主要发生在作为侧基的液晶基元之间。聚合物的核磁谱表现异常,其原固有待进一步研究。

The structure of a novel side chain liquid crystal polymer, poly-2,5-bis (4-methoxyben-zoyloxy) styrene, was studied by spectroscopic methods including FTIR, FT-RAMAN, 1H-NMR and 13C-NMR. The molecular structure was proved by both IR and RAMAN. However, unexpected results were given by the NMR methods. In the 1H-NMR spectrum, the peaks for the protons on the back-bone carbons are much smaller than that they would be if the numbers of different protons are considered. In addition, the 13C-NMR signals for the back-bone carbons are even undetectable if a pulse lepetition time of 1.5 seconds is used, which can, ho-wevar, be seen in the spectrum when a ionger pulse repetition time of 3 secends is used. A somewhat plausible explanation is given for these unusual observations. The temperature dependence of the spectroscopic properties is also discussed in terms of molecular interactions.