Preparation of electro conductive nano-composite from surface modified carbon nanotube and their application to sensing material

1.在Al粉和AlCl_3催化剂存在下，通过含二茂铁基团的聚合物与碳纳米管（CNT）和气相生长碳纤维（VGCF）表面芳环的配体交换反应，成功地实现了聚合物在CNT和VGCF上的接枝。接枝率（接枝聚合物占CNT的wt%）达到60.9%。研究还发现，聚（乙烯基二茂铁-co-甲基丙烯酸甲酯）接枝的百分比随着共聚物中乙烯基二茂铁含量的增加而增加。通过配体交换反应，将共聚物接枝到VGCF和碳微线圈表面。2.通过碳纳米管和VGCF表面的稠环与1，1 '-二羧基二茂铁的配体交换反应，成功实现了碳纳米管和VGCF表面羧基的引入。采用直接冷凝法将端羟基和端氨基聚合物如聚乙二醇（PEG）和聚己二酸乙二醇酯接枝到碳纳米管表面， 关于我们 在N，N '-二环己基马来酰亚胺存在下，CNT和VGCF的羧基与这些聚合物的端羟基发生了反应。3.研究了通过捕获Perhexa C在甲苯中于70℃热分解10 h所形成的具有过氧酯结构的自由基，在CNT上引入过氧酯基团的方法。结果，过氧酯基团被成功地引入到CNT表面上。通过滴定测定，CNT上引入的过氧基的量为9.5mmol/g。结果表明，在100℃下，碳纳米管表面引入过氧化酯基团可引发乙烯基单体自由基接枝聚合，得到相应的聚合物接枝碳纳米管。4.聚乙烯基二茂铁-甲基丙烯酸甲酯接枝碳纳米管在四氢呋喃等溶剂中的分散性较好。即使在4周后也几乎没有观察到聚合物接枝的CNT的沉淀。另外，聚合物接枝的VGCF和CNT在接枝聚合物中分散均匀，形成纳米复合材料，在PEG熔点50℃时，复合材料的电阻显著增加。结果表明，PEG接枝的VGCF/CNT复合材料具有正温度系数（PTC）特性，其电阻在甲醇、THF、甲苯等有机溶剂蒸气中突然增大，在干燥空气中迅速恢复到初始电阻。即使在暴露于甲醇蒸气和干燥空气20个循环后，电阻的响应性也是可再现的。少

1.The grafting of polymers onto carbon nanotube (CNT) and vapor grown carbon fiver (VGCF) by ligand-exchange reaction of polymers containing ferrocene moieties with aromatic ring of these surfaces was successfully achieved in the presence of Al powder and AlCl_3 as catalyst. The percentage of grafting (wt% of grafted polymer to CNT) reached to 60.9%. It was also found that the percentage of poly(vinyl ferrocene-co-methyl methacrylate) grafting increased with increasing vinyl ferrocene content of the copolymer. The copolymer was also grafted onto VGCF and carbon micro coil surface by use of the ligand-exchange reaction.2.The introduction of carboxyl groups onto CNT and VGCF surface was successfully achieved by the ligand-exchange reaction of polycondensed aromatic rings of these surfaces with 1,1'-dicarboxyferrocene. The grafting of hydroxyl and amino group terminated polymers, such as poly(ethylene glycol) (PEG) and poly(ethylene adipate), onto CNT surface was achieved by direct conden … More sation of carboxyl groups of CNT and VGCF with terminal hydroxyl groups of these polymers in the presence of N,N'-dicyclohexylcarbodiimide.3.The introduction of peroxyester groups onto CNT by the trapping of radicals having peoxyester moieties which were formed by the thermal decomposition of Perhexa C in toluene at 70℃ for 10 h was examined. As a result, peroxyester groups were successfully introduced onto CNT surface. The amount of peroxy groups introduced onto CNT was determined to be 9.5 mmol/g by titration. It was found that the radical graft polymerization of vinyl monomers was successfully initiated by the peroxyester groups introduced onto the CNT surface at 100℃ to give the corresponding polymer-grafted CNT. The percentage of grafting of ptoly(methyl methacrylate) reached to 6.6%.4.Poly(vinyl ferrocene-co-methyl methacrylate)-grafted CNT gave a stable dispersion in good solvent for grafted polymer, such as THF. The precipitation of the polymer-grafted CNT was scarcely observed even after 4 weeks. In addition, polymer-grafted VGCF and CNT readily and uniformly dispersed in grafted polymers to give nano-composites.It was found that electric resistance of the composites prepared from PEG-grafted VGCF and CNT drastically increased at melting point of PEG, 50℃. Therefore, the composites from PEG-grafted VGCF and CNT show positive temperature coefficient (PTC) characteristic.The electric resistance of the composites prepared from polymer-grafted VGCF and CNT suddenly increased in organic solvent vapor, such as methanol, THF, and toluene, and returns immediately to initial resistance when the composite was transferred in dry air. The responsiveness of electric resistance was reproducible even after 20 cycles of exposure to methanol vapor and dry air. Less