A critical review on nanotube and nanotube/nanoclay related polymer composite materials

Since the last decade, research activities in the area of nano-materials have been increased dramatically. More than a 1000 of journal articles in this area have been published within the last 3 years. Materials scientists and researchers have realized that the mechanical properties of materials can be altered at the fundamental level, i.e. the atomic-scale. Carbon nanotubes (hereafter called ‘nanotubes’) have been well recognized as nanostructural materials that can be used to alter mechanical, thermal and electrical properties of polymer-based composite materials, because of their superior properties and perfect atom arrangement. In general, scientific research related to the nanotubes and their co-related polymer based composites can be distinguished into four particular scopes: (i) production of high purity and controllable nanotubes, in terms of their size, length and chiral arrangement; (ii) enhancement of interfacial bonding strength between the nanotubes and their surrounding matrix; (iii) control of the dispersion properties and alignment of the nanotubes in nanotube/polymer composites and (iv) applications of the nanotubes in real life. Although, so many remarkable results in the above items have been obtained recently, no concluding results have so far been finalized. In this paper, a critical review on recent research related to nanotube/polymer composites is given. Newly-adopted coiled nanotubes used to enhance the interfacial bonding strength of nanocomposites are also discussed. Moreover, the growth of nanotubes from nanoclay substrates to form exfoliated nanotube/nanoclay polymer composites is also introduced in detail. q 2006 Elsevier Ltd. All rights reserved.