多壁碳纳米管/向列型液晶高分子复合材料的制备与表征

Preparation and Characterization of Multiwalled Carbon Nanotube and Nematic Liquid Crystalline Polymer Composites

合成了一种丙烯酸酯类向列相液晶单体LCM及其高分子LCP,采用溶液共混制备了不同配比的MCNT/LCP复合材料,其结构与性能通过FT-IR、1H-NMR、DSC、POM、SEM和荧光光谱表征。LCM与LCP均呈现向列相的线状织构与纹影织构,LCM的熔点与清亮点分别为149.2℃与172.1℃,而LCP的玻璃化温度与清亮点分别是53.1℃与239.4℃。多壁碳纳米管(MCNT)的加入并不改变LCP的液晶相类型与织构,当MCNT的质量分数从0.05%增加到5%时,对应复合材料的清亮点从255.9℃上升到270.1℃,而玻璃化温度呈现先升高后降低的趋势。此外,质量分数在1%以下的MCNT能均匀分散在LCP中,而且沿着液晶的矢量方向排列,起到了稳定液晶相的作用,但当MCNT质量分数为3%时,会出现明显的团聚现象。

The synthesis of a nematic acrylate monomer （LCM） and the corresponding polymer LCP was described. Moreover, multiwalled carbon nanotube （MCNT）/LCP composites containing 0.05 % --5 % MCNT were prepared by solution blending. Their structure and properties were investigated by FT：IR, 1H-NMR, differential scanning calorimetry （DSC）, polarizing optical microscopy （POM）, scanning electron microscope （SEM） and luminoscope. LCM and LCP exhibit threaded and schlieren texture. The melting temperature （Zm） and isotropic temperature （ Ti） of LCM are 149.2 ℃ and 172.1℃ , respectively. The glass transition temperature （Tg） and Ti of LCP are 53.1 ℃ and 239.4 ℃, respectively. The addition of MCNT in LCP does not change mesophase and texture type of LCP. When MCNT content increases from 0.05 % to 5 %, Ti of MCNT/LCP composites also increases, the corresponding Tg firstly increases and then decreases. When MCNT content is less than 1%, it can well disperse in LCP and arrange along vector orientational direction of liquid crystal molecules, moreover, MCNT as crystal nucleus makes the mesophase more stable. However, the agglomeration phenomena occurs when the content of MCNT is more than 3 % in LCP.