Effect of Copper Oxide Nanoparticles on the Structural, Thermal, Electrical, and Mechanical Properties of Cashew Gum/Polylactic Acid Biopolymer Nanocomposites

ABSTRACT

Biopolymer‐based nanocomposite films comprising polylactic acid (PLA) and cashew gum (CG), reinforced with different concentrations of copper oxide (CuO) nanoparticles, were developed to investigate their structural, optical, morphological, thermal, electrical, and mechanical characteristics. UV–visible spectroscopy revealed strong ultraviolet absorption and a decrease in direct and indirect bandgap energies upon the addition of nanoparticles. Fourier transform infrared (FTIR) spectroscopy indicated physicochemical interactions among CG, PLA, and CuO nanoparticles. X‐ray diffraction (XRD) analysis confirmed the semi‐crystalline nature of the synthesized nanocomposites. Field‐emission scanning electron microscopy (FESEM) and high‐resolution transmission electron microscopy (HR‐TEM) revealed uniform dispersion of CuO nanoparticles within the CG/PLA matrix at optimal loadings, while energy‐dispersive X‐ray (EDX) analysis confirmed their successful incorporation. Thermogravimetric analysis (TGA) demonstrated an increase in decomposition temperature with nanoparticle loading. Electrical characterization showed enhanced AC conductivity and dielectric constant with increasing temperature, along with a reduction in activation energy upon CuO addition. Mechanical analysis demonstrated a significant improvement in tensile strength, increasing from 42.83 to 57.69 MPa, along with enhanced stiffness. The combined improvements in optical properties, thermal stability, electrical conductivity, dielectric behavior, and mechanical stability suggest that the developed CG/PLA/CuO biopolymer blend nanocomposite films are potential candidates for a wide range of applications.