论文部分内容阅读
合成一种分子量分布窄、两嵌段侧链不同的新型聚(γ-苄基-L-谷氨酸)和聚(γ-十二烷基-L-谷氨酸)的二嵌段聚肽(poly(γ-benzyl-L-glutamate)-b-poly(γ-dodecyl-L-glutamate),PBLG-b-PDLG),并研究该嵌段聚肽的分子结构、热性能及液晶性.PBLG-b-PDLG的合成是利用N-羧酸内酸酐(N-carbonyl anhydride,NCA)法,以正己胺为引发剂,在0℃的条件下的氯仿溶液中,先将γ-苄基-L-谷氨酸NCA开环聚合获得了末端带胺基的活性PBLG-NH2沉淀后,再以其为引发剂加入γ-十二烷基-L-谷氨酸的NCA继续反应.氢核磁共振波谱(1H-NMR)和凝胶渗透色谱(GPC)用于表征两嵌段的摩尔比、分子量及其分布,发现嵌段聚肽的分子量分布只有1.07～1.09.由红外光谱(IR)的分析得知PBLG-b-PDLG的二次结构为刚直棒状的α-螺旋结构.利用示差扫描量热分析法(DSC)考察材料的热性质,发现不同组成的PBLG-b-PDLG有不同的热行为,而在100℃附近都出现了微弱的热致相转变.采用偏光显微镜观察PBLG-b-PDLG磁场取向膜的相变行为中发现其相结构不同于一般无规共聚物所呈现的胆甾液晶结构,同时用在PBLG-b-PDLG的二氯乙烷溶致液晶溶液中观察到一般近晶相所呈现的扇形织构.
A novel diblock peptide with poly (γ-benzyl-L-glutamic acid) and poly (γ-dodecyl-L-glutamic acid) with narrow molecular weight distribution and different diblock side chains was synthesized (poly-γ-benzyl-L-glutamate) -b-poly (γ-dodecyl-L-glutamate) and PBLG-b-PDLG were synthesized and their molecular structures, thermal properties and liquid crystallinity were studied. The synthesis of -b-PDLG was carried out by using N-carbonyl anhydride (NCA) method and n-hexylamine as initiator in a chloroform solution at 0 ° C. γ-Benzyl-L -amino-glutamic acid NCA ring-opening polymerization obtained after the active side of the PBLG-NH2 amine precipitation, and then as its initiator added γ-dodecyl-L-glutamic acid NCA continued the reaction of hydrogen nuclear magnetic resonance spectroscopy (1H-NMR) and gel permeation chromatography (GPC) were used to characterize the molar ratio, molecular weight and distribution of diblock. The molecular weight distribution of the block peptide was found to be only 1.07-1.09. Analysis by IR The secondary structure of PBLG-b-PDLG is a straight rod-like α-helical structure.The thermal properties of the material were investigated by differential scanning calorimetry (DSC) and the PBLG-b-PDLG was found to have different thermal behavior, In the vicinity of 100 ℃ there have been weak Thermal phase transition.It is found that the phase structure of the PBLG-b-PDLG magnetic field oriented film is different from that of the general random copolymer in polarized light microscopy, The fan-shaped texture exhibited by the general smectic phase was observed in the dichloroethane-soluble liquid crystal solution.