含二苯并-18-冠-6冠醚环的主链型液晶共聚酯的设计与合成(英文)

DESIGN AND SYNTHESIS OF MAIN CHAIN LIQUID CRYSTALLINE COPOLYESTERS CONTAINING DIBENZO-18-CROWN-6 UNITS

以4,4′-(α,ω-亚烷基二酰氧)二联苯甲酰氯(M1)、顺式-4,4′-双(4-羟基苯基偶氮)二苯并-18-冠-6(M2)、反式-4,4′-双(4-羟基苯基偶氮)二苯并-18-冠-6(M3)和1,10-癸二醇(M4)为单体,通过溶液共缩聚反应,合成了两个系列新的含联苯型液晶基元和偶氮型冠醚环的主链型液晶共聚酯.共聚酯的[η]在0·25～0·35和0·27～0·38之间.单体的化学结构通过IR、UV-Vis、1H-NMR、MS和元素分析等方法确证.共聚酯的性质采用[η]、DSC、TGA、WAXD和POM等方法进行了研究.发现所有的共聚酯加热到各自熔融温度以上都能形成向列相液晶态,可以观察到向列相的丝状织构或纹影织构或球粒织构.共聚酯的熔融温度(Tm)和各向同性温度(Ti)随共聚酯分子中柔性间隔基长度的增加而有规律地降低,含反式冠醚环的共聚酯的Tm和Ti均高于相应含顺式冠醚环的共聚酯的Tm和Ti.

Two series of novel main chain liquid crystalline copolyesters with biphenyl mesogenic units and azo type crown ether cycles were prepared via solution polycondensation from 4,4＇-（α,ω-alkanedioyloxy）dibiphenylyloyl dichloride （M1）, cis-4,4＇-bis （ 4-hydroxy-phenylazo ） dibenzo-18-crown-6 （M2）, trans-4,4＇-bis-（4-hydroxy-phenylazo）-dibenzo-18-crown-6 （M3） and 1,10-decanediol （M4） as the monomers.The intrinsic viscosity [ η] of the two series of copolyesters ranges from 0.25 - 0.35 dL/g and 0.27 - 0.38 dL/g, respectively. The structures of monomers were identified by elemental analysis, IR, UV-Vis, ^1H-NMR and MS. The properties of copolyesters were investigated by using DSC, TGA, WAXD and POM. All the copolyesters are able to form nematic mesophase after melting. The threaded texture, or ball granul texture or Schlieren texture of nematic phase can be observed on POM. Their melting temperature （ Tm ） and isotropic temperature （ Ti ） decrease regularly with increasing the length of flexible spacer in the copolyesters, and the Tm and Ti of copolyesters containing trans crown ether cycles are higher than those of the copolyesters containing cis crown ether cycles.