51
grown CNTs, with a greater rigidity and slightly higher entanglement, are robust
enough to survive the force of a percolating polymer, making them a much more
realistic option for mechanically-reinforced A-CNT composites.
Due to the compliancy of the PDMS matrix, these nanocomposites can be
dynamically stressed to large strains, and such testing has revealed that these
aligned CNTs in a composite matrix do impart not only significant improvement
over the neat polymer, but their anisotropy can result in loading-specific responses.
The thickness of the CNTs also plays a large role in their bulk properties, and axial
loading has revealed that the storage is very high until a critical strain threshold,
where the CNTs will enter a global buckling mode. Radial loading, however, largely
mimics the trend of the neat polymer, though the yield strain is significantly lower
due to polymer chain entanglement around the CNTs.
In addition to the further characterization of these composites, future work
will include extended cyclic testing to determine the fatigue behavior of these
polymer nanocomposites to gauge their viability in real world applications as
mechanical reinforcement. Also, by understanding the high-cycle behavior of these
materials, we can further shed light on the complicated interactions between these
nanomaterials and polymer matrices.