Thermal and electrical properties of nanocomposites based on acrylic copolymers and multiwalled carbon nanotube

Nanocomposites based on multiwalled carbon nanotubes (MWCNT) and various acrylic copolymers, poly(methyl methacrylate-co-butyl acrylate) (PMBA) and poly(methyl methacrylate-co-butyl acrylate-co-acrylic acid) (PMAA), were prepared and the effects of the copolymer composition on the thermal and electrical properties of the nanocomposites were investigated. The results showed that there was a decrease in the glass transition temperature (T(g)) with increasing MWCNT content in the nanocomposites based on the acrylic copolymers. This decrease in T(g) was attributed to the characteristics of the nanocomposites in which the compatibility between the matrix polymers and MWCNT were relatively poor and there was an increase in free volume at the interface. It was found that the critical concentrations, P(c)s, for the percolation of MWCNTs in terms of the electrical resistivity decreased with increasing acrylic acid content in the matrix polymers. In addition, the thermal conductivity of the nanocomposites increased with increasing MWCNT content if there was good compatibility between the matrix polymer and MWCNT while those of the nanocomposites with relatively poor compatibility between the matrix and MWCNT showed little change.