Tailoring mechanical and thermal behavior of HDPE via Ba–Sr–Ca hexaferrite incorporation

Using mechanical ball milling at filler loadings of 5-20 wt%, high-density polyethylene (HDPE) nanocomposites reinforced with BaSrCa hexaferrite nanoparticles were created, and their structural, mechanical, and thermal performance was thoroughly examined. The M-type hexaferrite phase was successfully incorporated into the HDPE matrix, as demonstrated by X-ray diffraction, and the composite crystallite size gradually decreased from 59.31 nm (5 wt%) to 50.38 nm (20 wt%). Effective filler integration was confirmed by Rietveld refinement, which showed a gradual increase in the BaSrCa volume percentage from 4.89% to 19.25% while the HDPE fraction fell proportionally. HDPE lattice characteristics (a: 7.418 → 7.410 Å, b: 4.940 → 4.933 Å, and c: 2.485 → 2.475 Å) show slight contractions that suggest interfacial stress and limited polymer chain mobility. As the filler content increased, mechanical testing showed a noticeable stiffening impact. Young's modulus rose from 144.35 MPa for pure HDPE to 191.35 MPa at 20 wt% BaSrCa (5 mm/min) and 239.04 MPa at 20 mm/min. While yield stress increased significantly from 16.48 MPa to 25.37 MPa, ultimate tensile strength showed a slight improvement from 24.44 MPa to 27.33 MPa. On the other hand, strain at break dropped dramatically from 536% to about 70%, indicating lower ductility because of filler-induced constraint. At greater BaSrCa concentrations, the thermal study revealed improved stability with a delayed commencement of deterioration and a higher residual mass. Overall, the findings show that BaSrCa nanoferrites considerably improve HDPE's strength, stiffness, and thermal stability at the expense of ductility. These composites are promising options for lightweight structural, electromagnetic, and heat-resistant applications because an ideal filler range of 10-15 wt% is found, providing a balanced combination of mechanical reinforcement and structural integrity.