CuO nanoparticle green synthesis and composite film production with PVA matrix

In recent years, the use of secondary metabolites in aqueous extracts of plant roots, stems, leaves and stalks for the synthesis of various nanoparticles has attracted attention as a new environmentally friendly technology. Copper (II) oxide (CuO) nanoparticles find use in many industrial areas such as solar energy systems, semiconductors, catalysts and gas sensors, due to their superior properties in micro-scale with the reduction of crystal size. In this study, a non-toxic, environmentally friendly and low-cost green synthesis method was developed for the synthesis of CuO nanoparticles using the aqueous extract of artichoke stem (Cynara Scolymus L.) as a reducing agent. The synthesized nanoparticles were characterized by UV-Vis spectroscopy (UV-Vis), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) method and scanning electron microscopy (SEM), and as a result of the developed method, spherical CuO nanoparticles (˂25 nm) was confirmed to be synthesized. Within the scope of the study, different composite and nanocomposite films were prepared by adding the synthesized CuO nanoparticles, polyethylene glycol (PEG), glycerine and gum acacia polymers in different ratios to the polyvinyl alcohol (PVA) matrix. The effects of the additives on the chemical structure, morphological properties, thermal degradation behaviors, mechanical and electrical properties of composite and nanocomposite films were investigated by FTIR spectroscopy, SEM, thermogravimetric analysis (TGA), tensile tests and dielectric constant measurements, respectively. As a result of the FTIR analysis, it was determined that new hydrogen bonds were formed between PVA chains and hydroxyl groups in the structure of PEG molecules. The data obtained from TGA and dielectric constant measurements showed that the percentage of residue at 600oC was increased by 81% and the dielectric constant by 30% compared to pure PVA film as a result of the study. As a result of the tensile tests, it was determined that the tensile strength (38.85 MPa) of the pure PVA film increased by 503% to 234.34 MPa with the addition of 20% PEG and 3% CuO nanoparticles. Key words: Green synthesis, Copper oxide nanoparticle, Polyvinyl alcohol, Polyethylene glycol, Nanocomposite film.