The Kentera¿¿¿¿¿¿¿ polymer treatment system was investigated as a potential candidate for improving the properties of polymer nanocomposites. Polymer treatments have the ability to improve dispersion and interfacial bonding of fillers within a polymer matrix. This investigation focused on one particular Kentera¿¿¿¿¿¿¿ polymer and its ability to compatibilize carbon nanotubes with polycarbonate.
In this study untreated carbon nanotubes, CNT’s, and non-wrapping polymer treated CNT’s were mixed with polycarbonate, PC, in order to produce polymer nanocomposites. The nanocomposites were created by diluting 15 wt.% masterbatches into virgin PC, and then compounding them using a Killion single screw extruder. These compounded samples were then pelletized for further processing. Thermal and rheological analysis was performed on the pelletized samples.
Differential scanning calorimetry was used to perform the thermal analysis. The results showed the glass transition temperature of the PC was unaffected by the addition of untreated or treated CNT’s. The rheological behavior of these nanocomposites was characterized using a capillary rheometer. The results showed that the polymer treatment of the CNT’s helped to plasticize the nanocomposites. The rheological data shows a significant decrease in viscosity between the treated and untreated nanocomposites. Also, depending on how the materials are processed for end-use products, such as compression or injection molding, a significant change in rheological behavior is observed between the 0.5 wt.% and 2 wt.% nanocomposites.
The pelletized samples were then injection molded into ASTM standard tensile, flex, and impact bars, which were tested according to ASTM standards. The addition of CNT’s seemed to only improve the flexural properties of the PC. Also, a shear rate study was conducted using three different injection velocities. This investigated how increasing the shear rate during molding can affect the mechanical properties of the polymer nanocomposites. The results showed that increasing the shear rate did not significantly affect the mechanical properties of either the untreated or treated nanocomposites.
Overall, the Kentera¿¿¿¿¿¿¿ polymer treatment supplied minimal mechanical property improvement to the nanocomposites, but did provide very interesting rheological data. This Kentera¿¿¿¿¿¿¿ polymer treatment makes PC-CNT nanocomposites easier to process by lowering the viscosity of the PC matrix.