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通过聚乙二醇单甲醚钠盐(MPEG-Na)和4-甲氧基-4′-(6-羟基己氧基)偶氮苯钠盐(AZO-Na)与六氯三聚磷腈的分步取代反应,合成了含偶氮苯基团的A3B3六杂臂星型聚合物[NP(MPEG550)(AZO)]3和[NP(MPEG1100)(AZO)]3.采用傅里叶红外光谱(FT-IR)、核磁共振谱(1H-NMR)和凝胶渗透色谱(GPC)手段确证了聚合物的基本结构,所得两种聚合物为接近单分散的多杂臂星型聚合物.采用热分析(DSC)和热台偏光显微镜(POM)研究了两种星型聚合物的热转变行为.结果表明,[NP(MPEG550)(AZO)]3具有可逆的热致液晶转变行为(TS-N=60.5℃;TN-I=104.7℃),为双向性液晶聚合物.而对于[NP(MPEG1100)(AZO)]3,观察不到液晶相转变行为,[NP(MPEG1100)(AZO)]3聚合物中柔性PEG链段含量过高可能导致其偶氮苯链段难局部有序而不能呈现液晶相转变.
Polyethylene glycol monomethyl ether acetate (MPEG-Na) and 4-methoxy-4 ’- (6-hydroxyhexyloxy) azobenzene sodium salt (AZO-Na) (AZO)] 3 and [NP (MPEG1100) (AZO)] 3 containing azobenzene groups were synthesized by Fourier transform infrared spectroscopy The basic structure of the polymer was confirmed by FT-IR, 1H-NMR and GPC. The obtained two polymers were nearly monodisperse multi-arm star polymers. The thermal transition behavior of the two star polymers was investigated by thermal analysis (DSC) and thermal Polarizing Microscope (POM). The results show that [NP (MPEG550) (AZO)] 3 has reversible thermotropic liquid crystal transition behavior -N = 60.5 ° C; TN-I = 104.7 ° C), and the liquid crystal phase transition behavior was not observed for [NP (MPEG1100) ] 3 The high content of the flexible PEG segment in the polymer may lead to its azobenzene segment is difficult to local order and can not show the liquid crystal phase transition.