Advances in <scp>PEKK</scp> Thermoplastic Composites: Reinforcing With <scp>MWCNTs</scp> and <scp>GNPs</scp> for Enhanced Performance

ABSTRACT Polyetherketoneketone (PEKK) is a highly regarded material in polymer science due to its outstanding thermal stability, mechanical strength, and chemical resistance. Despite substantial research on PEKK composites reinforced with CNTs and GNPs, two primary challenges remain: inconsistent glass transition temperature behavior at varying filler contents, leading to unpredictable shifts in both thermal and mechanical performance, and the absence of direct comparisons under uniform processing conditions that would allow quantitative evaluation of each filler's effect. In this work, PEKK/MWCNT and PEKK/GNP nanocomposites were produced via the same hot‐press molding protocol and systematically evaluated for thermal and mechanical performance, electrical conductivity (using S ‐value analysis) and microstructural morphology. A range of mechanical tests, including tensile, Charpy impact, and hardness tests, were conducted alongside physical analyses such as differential scanning calorimetry (DSC), thermogravimetric analysis, dynamic mechanical analysis (DMA), thermal conductivity, electrical conductivity, and scanning electron microscopy (SEM). The results demonstrated that both MWCNTs and GNPs significantly enhanced PEKK's properties. The incorporation of MWCNTs raised the glass transition temperature ( T g ) to 169°C and the crystallization temperature ( T c ) to 327°C, whereas GNPs increased the decomposition temperature ( T d ) to 572°C. Adding 1 wt.% of either nano‐additive notably improved tensile and flexural strength, while an optimal concentration of 0.1 wt.% was determined for Charpy impact performance. Additionally, higher concentrations resulted in exceptional electrical and thermal conductivity.