【摘要】 合成了4种以间苯二甲酸、间苯二酚为中心,硝基为端基的芳香酯类香蕉形液晶(M1～M4)。利用红外光谱(IR)、核磁共振谱(1 H NMR)及元素分析对其分子结构进行了表征,通过差示扫描量热(DSC)、偏光显微分析(POM)、热重分析(TG)对其介晶性能、相行为及热稳定性进行了研究。结果表明,所合成的香蕉形化合物(M1～M4)均有液晶性,呈现树叶、马赛克、扇形、球粒及纹影织构;升、降温时的液晶区间分别为32.9～57.2℃(M1除外)与28.4～96.5℃;随着分子刚性增加,它们的tm、ti、tic值明显提高;该类物质热稳定性良好,5%热失重温度均在285℃以上。更多还原

【Abstract】 A series of novel banana-shaped liquid crystals M1-M4 based on isophthalic acid or resorcinal as a core and nitryl as terminal groups was synthesized by aromatic esterification.Their chemical structures were confirmed by FT-IR,1H NMR and elemental analysis,their mesomorphic properties and phase behavior were investigated by differential scanning calorimetry(DSC),polarizing optical microscopy(POM) and thermograrimetric analyzer(TG) measurements.The results showed that M1-M4 were thermotropic liquid crystals.In mesomorphic state,they displayed dendritic,mosaic,fan-shaped,droplet and schlieren texture severally.The mesophase range was 32.9-57.2℃(except M1) during heating,while it was 28.4-96.5℃ during cooling.With increasing rigidity of M1-M4,their tm,ti,tic improved obviously.The temperatures when 5% weight loss occurred were higher than 285℃,which revealed that the synthesized banana-shaped liquid crystals M1-M4 had a high thermal stability.更多还原