CNT reinforced PEI and PEEK nanocomposites: A comparison on the thermal and rheological properties

Multifunctionality brought by nanomaterials such as carbon nanotubes (CNTs) to high-performance thermoplastics brings several opportunities for tuning the properties in advanced applications. Here, polyetherimide (PEI) and polyether ether ketone (PEEK), amorphous and semi-crystalline polymers, were chosen to explore the thermal transitions and rheology linked to morphological properties of CNT-reinforced PEI and PEEK nanocomposites. A custom-built twin-screw extruder was employed to manufacture the CNT/PEI and CNT/PEEK nanocomposites at 1, 3, and 5 wt%. The thermal stability and glass transition temperature (T_g) of nanocomposites were not significantly affected; however, the crystallization ratio of the PEEK nanocomposites was increased to 29.3% for 1 wt% CNT/PEEK. Rheological analysis showed that storage modulus was enhanced in both polymers. Rheological percolation was considered to be below 1 wt% CNT for both PEI and PEEK. The lowest shear-thinning exponents were found as 0.35 and 0.26 between 10² and 10³ rad/s for 5 wt% CNT/PEI and CNT/PEEK, respectively.