芳香族偶氮苯封端的液晶聚氨酯膜的制备及其液晶性能

Synthesis and Liquid Crystalline Properties of Liquid Crystalline Polyurethane Film with Aromatic Azo Benzene End Capping

以苯胺或对硝基苯胺为主要原料,经重氮偶合反应制得液晶基元对氨基偶氮苯(LC1)或对硝基偶氮苯胺(LC2),再用聚氨酯预聚体[由聚乙二醇(PEG400,含-OH)和二苯基甲烷二异氰酸酯(MDI,含-NCO)制得,r=n(-OH):n(-NCO)]封端合成了一系列偶氮液晶聚氨酯膜LCPU1r和LCPU2r,其结构和液晶性能经UV,IR,TGA,POM与XRD表征。结果表明,LCPU1r和LCPU2r为具有良好热稳定性的热致型向列型液晶聚氨酯。LCPU31/4的接触角较大,耐水性相对较佳,硬度也相对适中。

Aromatic azo benzene liquid crystalline units,LC1 or LC2,were prepared by diazo coupling reaction from aniline or p-nitroaniline.A series of azo liquid crystalline polyurethane films（LCPUr1 and LCPUr2） were synthesized by the end capping reaction of LC1 or LC2 with polyurethane prepolymer which were prepared by different ratio[r=n（-OH）：n（-NCO）] polyethylene glycol（PEG400,containing-OH） and 4,4′-diphenylmethane diisocyanate（MDI,containing-NCO）.The structures and film properties of LC and LCPU were characterized by UV,IR,TGA,DSC,POM and XRD.The results indicated that LCPUr1 and LCPUr2 were thermotropic nematic liquid crystalline polyurethane and showed good thermal stability.LCPU3/41 exhibited a relatively modest value of static contact angle,the water resistance and hardness properties.