Integrated PLA/LLDPE nanocomposites with compatibilizer and hydroxyapatite-zinc oxide: Mechanical, physical, thermal, and morphological properties

Abstract

The integration of Polylactic Acid (PLA)/Linear Low-Density Polyethylene (LLDPE) nanocomposites with Hydroxyapatite-Zinc Oxide hybrid nanoparticles (HAp-ZnO HNPs) as fillers and LLDPE-grafted-Oleic Acid (LLDPE-g-OA) as a compatibilizer was successfully conducted. This study examines the improvement of mechanical, physical, thermal, and morphological properties of PLA/LLDPE blends through the incorporation of HAp-ZnO HNPs and LLDPE-g-OA (LO) to enhance their strength, durability, and biodegradability. The HAp-ZnO HNPs were synthesized by mixing HAp and ZnO in an ethanol-water solution (20:80), adjusting the pH to 11 with ammonium hydroxide, and then applying sonication, filtration, washing, and drying. The nanocomposites were prepared by blending PLA, LLDPE, LO, and 5.0 wt. % HAp-ZnO HNPs in an internal mixer at 160 °C. The incorporation of HAp-ZnO HNPs improved tensile strength (9.171 MPa), elongation at break (52.863 %), and Young's modulus (487.327 MPa) while reducing water absorption to 0.72 %. HAp-ZnO HNPs also accelerated biodegradation, increasing weight loss from 0.73 % at 15 days to 15.81 % at 90 days. Thermal analysis showed enhanced thermal stability, a higher melting point, and faster degradation due to HAp-ZnO HNPs. FTIR spectra revealed complex interactions among the materials, and morphological analysis confirmed good compatibility with evenly nanoparticle dispersion. These findings indicate the potential of HAp-ZnO HNPs as effective fillers and co-compatibilizers for improving the overall properties of PLA/LLDPE blends.