Rheological and Nonlinear Mechanical Behavior of PLA / MWCNT / MMT Nanocomposites Under Cyclic Loading: Influence of Hybrid Filler Concentration and Dispersion

ABSTRACT This study examines the rheological and nonlinear mechanical behavior of polylactic acid (PLA) nanocomposites reinforced with hybrid multi‐walled carbon nanotubes (MWCNTs) and montmorillonite (MMT) nanoplatelets. Three hybrid compositions were investigated, all maintaining a fixed MMT:MWCNT weight ratio of 2:1, and compared against neat PLA. Oscillatory shear rheometry revealed that, at low frequencies, the hybrid nanocomposite with 2 wt% total filler content exhibited a frequency‐independent storage modulus and yield stress—indicative of pseudo‐solid‐like behavior and the formation of a percolated filler network. Cyclic tensile testing further demonstrated enhanced mechanical performance, with the 2 wt% hybrid sample showing a 25% increase in elastic modulus and a 38% improvement in toughness under cyclic loading compared to neat PLA. Notably, the incorporation of 1.0 wt% MMT/MWCNT led to significant reductions in deformation‐related degradation: 60% in damage and 100% in plasticity. Transmission electron microscopy (TEM) confirmed a homogeneous dispersion of the hybrid fillers, which supports the observed synergistic improvements in both rheological and mechanical properties. These findings highlight the effectiveness of MMT/MWCNT nanofillers in tailoring the structure–property relationships of PLA‐based materials. The resulting nanocomposites offer enhanced performance and processability, making them promising candidates for structural, packaging, and automotive applications where lightweight, biodegradable, and mechanically robust materials are essential.