The Physical Characteristics of Nanofiller and Interfacial Regions in Nanocomposites with Polymer/Carbon Nanotubes and Elastomeric Vitreous Matrix

Abstract

Purpose. The purpose of this study is to separately defi ne the elasticity modulus of nanocomposites with polydicyclopentadiene/multilayer carbon nanotubes, specifi cally, of the nanofi ller and interfacial regions. To achieve this we used a micromechanical model. Results. According to our estimates, the elasticity modulus of carbon nanotubes, or aggregates, in polymer matrix nanocomposite is approximately two orders of magnitude less than the nominal value of this parameter for one single carbon nanotube, while the elasticity modulus of interfacial regions is approximately two times than the elasticity modulus of the matrix polymer. Our data clearly demonstrates that it’s incorrect to use the nanofi ller’s nominal characteristics, its elasticity modulus in particular, for determining the corresponding characteristics of the nanocomposite. Nevertheless, it’s possible to use the real elasticity modulus values of carbon nanocomposite aggregates when using the general rule of mixtures to determine this value for the nanocomposite with suffi cient accuracy. It’s important to note that the elasticity modulus of carbon nanotubes in an elastomeric matrix is much lower than the elasticity modulus in a vitreous matrix even if it’s the same nanocomposite. This means that the given parameter is determined not only by the size and structure of the nanofi ller aggregates, but also other factors, such as the stiffness of the polymer matrix around the aggregate, the effectiveness with which the polymer matrix transfers mechanical stress to the nanofi ller, and so on. When we used a modifi ed rule of mixtures to determine the elasticity modulus of nanocomposites, we discovered that the so called length effi ciency factor of carbon nanotubes, which is calculated using the modifi ed rule of mixtures, is much (several orders of magnitude) lower than the one proposed theoretically, and that is especially evident in case of nanocomposites with an elastomeric matrix. Conclusion. Thus, we conclude, that the elasticity modulus of nanocomposite components is a strong function of their phase state, and that it’s possible to determine the real characteristics of these components by correctly using the rule of mixtures.

Keywords

• nanocomposite
• carbon nanotubes
• polymer matrix
• elasticity modulus
• phase state