三聚磷腈为核的A3B3六杂臂偶氮苯星型聚合物的合成及其热致液晶行为研究  

SYNTHESIS AND THEIR THERMOTROPIC LIQUID CRYSTALLINE BEHAVIOR OF CYCLOTRIPHOSPHAZENE BASED A3B3 MIKTOARM AZOBENZENE-CONTAINING STAR-SHAPED COPOLYMERS

作　　者：周波轩[1] 张兴宏[1] 孙学科[1] 傅智盛[1] 王齐[1] 范志强[1] 戚国荣[1] 

机构地区：[1]浙江大学高分子科学与工程学系高分子合成与功能构造教育部重点实验室,杭州310027

出　　处：《高分子学报》2009年第8期735-740,共6页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号20704034);中国博士后科学基金(基金号20060400339)资助项目

摘　　要：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.A new type of A3B3 six-arm azobenzene-containing star-shaped copolymers based on cyclotriphosphazene was prepared by stepwise nucleophilic substitution of hexachlorocyclotriphosphazene, using the sodium salt of methoxy poly（ethylene glycol） （MPEG-Na） and the sodium salt of 4-methoxy-4′-（6-hydroxyhexyloxy）azobenzene （AZO-Na） in sequence. Structures of the resultant copolymers [ NP （MPEG550） （AZO） ] 3 and [ NP （MPEG1100）- （AZO） ]3 were characterized by Fourier transform infrared spectroscopy （FT-IR）, proton nuclear magnetic resonancespectroscopy （^1H-NMR） and gel permeation chromatography （GPC）. Thermal properties of both six-arm azobenzenecontaining copolymers were investigated by differential scanning calorimetry （DSC） and polarizing optical microscopy （POM）. DSC result showed that [ NP（MPEG550） （AZO）]3 showed reversible thermotropic liquid crystalline （LC） behavior （ TS-N = 60.5℃ ; TN-1 = 104.7℃ ,by the second heating DSC curve） and was an enantiotropic LC polymer. Nematic droplets texture was observed by POM, but smectic-to-nematic translation was not clear. This might berelated to the complex LC phase transition process with the unique molecular structure of [ NP （MPEG550）- （AZO） ]3. It was not observed the thermotropic LC transition of [ NP（MPEG1100）（AZO）]3 by DSC and POM. This might be the result of the difficulty of crystallization of azobenzene segment linked to the long and flexible PEG chains with big volume fraction in the [ NP（MPEG1100）（AZO）]3-Thermotropic liquid crystalline behavior of such A3B3 polymers was mainly relevant to the chemical property and volume fraction of different arms.

关 键 词：杂臂星型聚合物 偶氮苯 磷腈 液晶 

分 类 号：O631.3[理学—高分子化学]