Green Nanocomposites of PLA / PBAT Reinforced With Fe ₃ O ₄ and GNP : EMI Shielding, Mechanical, Thermal, and Morphological Analysis

ABSTRACT This study focuses on the bio‐based green nanocomposites formed by melt‐mixing PLA and PBAT in a 70/30 weight ratio, with Fe ₃ O ₄ and Graphene Nanoplatelets (GNP) as the nanoparticles. Reinforcement with Fe ₃ O ₄ (3, 5, and 7 phr), GNP (3, 5, and 7 phr), and their hybrid was used to evaluate improvements in electromagnetic interference shielding effectiveness (EMI SE), thermal, mechanical, and morphological properties of the PLA/PBAT system. GNP 7 phr and hybrid 7 phr show high SE, primarily from absorption due to magnetic dipoles in Fe ₃ O ₄ based and interfacial polarization in GNP based nanocomposites. The 70/30 blend shows a tensile strength of 31 MPa and elongation of 4.6%, while the nanocomposites range from 22 to 30 MPa and 2%–3.2%, respectively—except for 3 phr Fe ₃ O ₄ , which reaches 35 MPa and 2.7%. However, in fracture toughness, the critical stress intensity factor (K _IC ) increased from 1.56 to 5.7 MPa.m ^0.5 and strain energy release rate per unit area (G _IC ) increased from 1.68 to 18.39 kJ/m ² for the 70/30 to 3 phr hybrid. XRD confirms Fe ₃ O ₄ phase retention in nanocomposites. TGA shows improved thermal stability for GNP and the hybrid composition. SEM evaluated PBAT dispersion in PLA, and FTIR showed no chemical interaction between the materials.