Thermal and mechanical properties of polyimide nanocomposites

Interest has grown in recent years on the effects of nano-sized fillers on the thermal, mechanical, and electrical properties of polymeric systems. In particular, we are interested in studying the changes in mechanical and thermal properties of thermosetting polyimides as nano-sized fillers are added in increasing levels of concentration. The results are compared to micron-sized filled polyimides of similar compositions. We have observed dramatic increases in elongation to failure, scratch hardness and thermal conductivity while the tensile modulus does not change significantly. A change in stress state around nanoparticles during deformation is the possible reason for the observed improvement in tensile properties. Thermal conductivity of the filled polymer systems seemed to be most affected by the surface treatment of the nano-fillers. Improved interactions between the filler and the matrix is suggested as a possible explanation for these conductivity differences.