Characterization of mechanical properties of multiwalled nanotube polymer composites

Multiwalled carbon nanotubes are dispersed in polycarbonate matrices using a novel solution mixing technique and dynamic load tests are performed to characterize the storage and loss modulus. Tests are also performed with pristine polycarbonate (no carbon fillers), to compare the response of the two materials. The test results indicate that as the strain amplitude is increased, the storage modulus decreases in conjunction with an increase in the loss modulus. This suggests that at large strain levels the adhesion between the nanotubes and polymer is not strong enough to prevent interfacial slip, resulting in frictional sliding at the tube-polymer interfaces. This debonding at the filler-matrix interface is responsible for the observed decrease in storage modulus and increase in loss modulus. The nanotube-polymer sliding energy dissipation mechanism shows potential to reliably and efficiently deliver high levels of structural damping to polymer structures.