利用笼形聚倍半硅氧烷增强多壁碳纳米管在水溶液中的分散性

摘要

Polyhedral oligomeric silsesquioxane (POSS) was used as a physical dispersant to disperse multi-walled carbon nanotubes (MWNTs) in aqueous solution based on their strong interactions.The concentration and stability of MWNTs/POSS aqueous dispersion were characterized by UV-Vis absorbance.Zeta potentials of the aqueous dispersion and weight percentage of the supernatant after centrifugation were measured,while transmission electron microscope (TEM) was used to observe the conjugation state of POSS and MWNTs.Results showed that dispersion capability and stability of MWNTs in aqueous solution were significantly improved by POSS,whereas the dispersion efficiency largely depended on the structure of R organic groups.Among the five kinds of POSS investigated in this study,octaisobutyl POSS (POSSC) presented the best dispersion effects on MWNTs.On this basis,the optimized conditions to disperse MWNTs by POSSC were found out to be:MWNTs concentration of 30 mg/L and the weight ratio between POSS and MWNTs of 1.Under these conditions,POSSC can be well adsorbed onto MWNTs surface,resulting in stable MWNTs/POSS aqueous dispersion.This dispersion method is facile,effective and nondestructive,and the obtained MWNTs/POSS dispersion can be used for nanocomposite construction.%以笼形聚倍半硅氧烷(POSS)为物理分散剂,利用POSS与多壁碳纳米管(MWNTs)间较强的相互作用,在水溶液中对MWNTs进行分散.借助紫外吸光度对POSS分散的MWNTs浓度和稳定性进行了表征,测定了分散液的Zeta电位和离心后上清液中固体物质的质量分数,并用透射电镜观察了POSS与MWNTs间的结合情况.结果表明,POSS可以显著提高MWNTs在水溶液中的分散性,且提高程度与其有机官能团R的结构有关.在所采用的五种POSS中,八异丁基笼形聚倍半硅氧烷(POSSC)的分散效果最好.在此基础上,优化得到POSSC分散MWNTs的最佳条件,即MWNTs浓度为30 mg/L,POSSC和MWNTs的质量比为1.此时,POSSC可较好地吸附在MWNTs表面对其进行分散,得到具有良好稳定性的MWNTs水分散液.该分散方法简单高效且不破坏MWNTs的完整结构,所得分散液可用于复合材料的制备.