聚乙烯基吡咯烷酮修饰多壁碳纳米管的研究

MULTI-WALLED CARBON NANOTUBES MODIFIED BY POLY(VINYL PYRROLIDONE)

采用超声波辅助技术,研究了两亲性聚合物聚乙烯基吡咯烷酮(PVP)修饰多壁碳纳米管(MWNTs)的效果、作用机理及影响因素.研究结果表明在适合的条件下两亲性聚合物PVP可以被引入到多壁碳纳米管表面,修饰后的MWNTs在DMF、乙醇和水等溶剂中具有良好的分散性.通过红外光谱(FTIR)和拉曼光谱(Raman)分析表明,两亲性聚合物与MWNTs之间产生了化学接枝作用,高分辨透射电镜分析表明两亲性聚合物不均匀地存在于MWNTs的表面和端部.两亲性聚合物的浓度对接枝量的影响不大,但超声波作用时间对MWNTs表面两亲性聚合物PVP的接枝量有较大的影响,在超声时间为4h时接枝量最大.两亲性聚合物修饰效果不同于表面活性剂,采用表面活性剂十二烷基苯磺酸钠(SDBS)修饰的MWNTs经过洗涤过滤后,不能重新溶于水中,而两亲性聚合物PVP修饰的MWNTs可以重新溶解.

MWNTs were modified by amphiphilic polymer poly（vinyl pyrrolidone） （PVP） with ultrasonic assistance methods. The modified MWNTs were characterized by Fourier transform infrared spectroscopy （FTIR）, thermogravimetry （TG）,high-resolution transmission electron microscopy （TEM） and Raman spectrum. The results show that the surface of modified MWNTs was covered by PVP at special conditions. Modified MWNTs exhibit remarkable dispersion in water, glycol and dimethyl formamide （DMF）. FTIR spectrum analysis show that amphiphilic polymer existsd on the surface of MWNT. Raman spectrum analysis show that the G band of modified MWNTs shifts to high wavenumber and is divided into two bands, which indicates that the chemical graft reaction has occurred between MWNTs and the amphiphilic polymer. TEM shows that the amphiphilic polymer unevenly covered on the surface and ends of modified MWNTs. The content of the amphiphilic polymer had little effect on graft mass, but the ultrasonic time affected the graft mass greatly, and the graft mass of PVP reached a maximum, when the ultrasonic time was 4 h. The modifying effect of the amphiphilic polymer was different from that of surfactant. MWNTs modified with surfactant SDBS can＇t dissolve in water again after washing and filtration, but MWNTs modified with amphiphilic polymer can dissolve in water again.