Preparation and electrical properties of chemically functionalized carbon nanotube/polymer composites pp.705-726
Authors: (Qun Li, Qingzhong Xue, Department of Materials and Chemical Engineering, Taishan University, Peopleís Republic of China, and others)
Abstract: Since the discovery of the carbon nanotubes (CNTs) by Iijima in 1991, CNTs have been widely studied in the past few years because of their extraordinary electrical, thermal and mechanical properties. They have been pursued extensively to enhance the electrical properties of the polymer matrix by using CNTs as the nanofibers. However, owing to the high surface energy, the dispersion of the CNTs in polymer matrix becomes the very difficult problem. In order to solve this problem and make use of the unique properties of the CNTs, the chemical functionalization has been introduced in recent years. The interfacial characteristics between the CNTs and the polymer matrix could also be changed by the chemical functionalizaton. In this chapter, we summarize the preparation method of CNT chemical functionalization. And the electrical properties of the chemically functionalizd CNT/polymer composites were investigated. Firstly, the noncovalent functionalizations and the covalent functionalizations, for instance, the carboxylic, amino, fluorin, ester functionalizations, were summarized. Not only the solubility and compatibility of the CNTs, but also the interfacial characteristics between the CNTs and the polymer matrix could be improved by the chemical functionalizations. Secondly, the electrical properties of the chemically functionalized multiwalled carbon nanotube/poly(vinylidene fluoride) (MWCNT/PVDF) composites were investigated. The electrical conductivity of the polymer composites increases remarkably after the MWCNT concentration approaches the percolation thresholds. And the dielectric constant of the polymer composites also increases very much. However, the electrical conductivity and the dielectric constant of the chemically functionalized MWCNT/PVDF composites are different from the pristine MWCNT/PVDF composites, which can be attributed to the interface effect between the MWCNTs and the polymer.