ABSTRACT
Polymer nanocomposites have been an area of active research for the last 20 years. The field is relatively young, essentially starting in the late 1980s with the discovery by Toyota Research and Development Labs that some important properties of polymers could be improved upon even as their total materials, cost was reduced by introducing clays as additives. As fibers, carbon nanotubes (CNTs) can be considered one-dimensional molecules. Their radius reduces to zero size while their lengths are typically on the order of microns. The high surface free energy of CNTs is more often a hindrance than a help, as it leads to the formation of tight bundles of CNTs. Purification methods most commonly involve acid treatments and/or high-temperature annealing treatments. "Physical functionalization" of CNTs refers to noncovalent adhesion of an intermediary molecule to the CNT sidewall, hindering aggregation. Polymer composites take advantage of the appealing properties of the matrix polymer while improving or imparting specific properties using nanofillers.
