Coupled Reinforcement Mechanisms in TC / HT Nano Bi‐Filler Polypropylene Composites: Implications on Static Mechanical, Thermal, and Creep Behavior

ABSTRACT

This study investigates the synergistic effect of bi‐nanofillers, 0D tungsten carbide (TC), and 1D halloysite nanotubes (HTs) on the thermal, static, and long‐term mechanical properties of polypropylene (PP). At an optimum filler loading of 0.5 wt% TC and 1 wt% HTs (PP/0.5TC/1HT), tensile strength, critical stress intensity factor and strain energy release rate were found to be increased by 54%, 67% and 91%, respectively, compared with PP due to the pinning and intertwining effects of dual nanofillers. Various theoretical models were employed to predict the strain energy release rate and radius of the plastic zone of the nanocomposite system. A reduction in the nominal radius of the plastic zone observed in PP/0.5TC/1HT was due to the higher Young's modulus exhibited by the samples. The fractographs of the hybrid nanocomposite revealed a semi‐brittle fracture with shallow and well‐defined riverlines. The creep analysis elucidated a lower strain rate for the PP/0.5TC/1HT owing to the uniform dispersion of nanofillers as observed in TEM micrographs. The hybrid nanocomposite sample showed higher thermal stability, with a 24% increase in activation energy and a 130% decrease in mass loss rate, compared to PP, which can be attributed to restricted chain mobility and the barrier network provided by the fillers.