有机醇改性多壁碳纳米管/水性聚氨酯复合材料

Organic alcohol modifieded multi-walled carbon nanotubes/waterborne polyurethane composites

将多壁碳纳米管(MWCNTs)羧基化和酰氯化,再分别和乙二醇(EG)、丙三醇(GL)以及二羟甲基丙酸(DMPA)反应合成3种亲水性MWCNTs,并将其与水性聚氨酯(WPU)混合,固化制得MWCNTs/WPU复合材料。采用透射电镜,扫描电镜,傅里叶红外光谱和同步热分析仪以及乳液粒径,流变性,拉伸性能和导电率测试研究了有机醇改性MWCNTs/WPU复合材料的性能。结果表明,改性MWCNTs的接枝率高于19.8%,在水和WPU乳液中分散性得到显著改善。接枝率越高,MWCNTs的水溶性越好,复合乳液平均粒径越小,复合材料的力学性能越好,导电率越高。质量分数1.5%的原始MWCNTs/WPU复合材料比WPU膜的拉伸应力提高了32%,而相同用量的MWCNTs-EG、MWCNTs-GL和MWCNTs-DMPA与WPU的复合材料则较其分别提高60%、67%和72%。其导电率达6.3×10^-5 S/cm以上,比原始MWCNTs复合材料提高了3个数量级。

The multi-walled carbon nanotubes (MWCNTs)were carboxylated and acylated,and then reacted with ethylene glycol (EG), glycerol (GL)and dimethylolpropionic acid (DMPA)respectively to synthesize three hydrophilic MWCNTs.The products were mixed with waterborne polyurethane (WPU)and cured to produce MWCNTs/WPU composites.The properties of organic alcohol modified MWCNTs/WPU composites were investigated by transmission electron microscopy,scanning electron microscopy,Fourier transform infrared spectroscopy,simultaneous thermal analyzer and testings of emulsion particle size,rheology,tensile properties and conductivity. The results showed that the grafting ratio of modified MWCNTs was higher than 19.8%,and the dispersibility in water and WPU emulsion were significantly improved.The higher the grafting rate,the better the water solubility of MWCNTs.The smaller the average particle size of the composite emulsion,the better the mechanical properties of the composite and the higher the electrical conductivity.The tensile stress of original MWCNTs/WPU composite with a mass fraction of 1.5%was increased by 32%comared with that of the WPU film, while the same amount of MWCNTs-EG,MWCNTs-GL and MWCNTs-DMPA and WPU composites was increased by 60%,67%and 72%,respectively.Its electrical conductivity was above 6.3×10^-5 S/cm,which was three orders of magnitude higher than the original MWCNTs composite.