Influence of NiO and La2O3 nanoparticles on the optical, mechanical and electrical properties of PVAc-PMMA blend: a comparative study

Nano-sized metal oxides are fascinating materials as fillers used for improving the polymeric materials' performance and expanding their multifunctionality. Two metal oxides; NiO and La2O3 nanoparticles (NP) were prepared and introduced into poly(vinyl acetate)/poly(methyl methacrylate), PVAc/PMMA blend via solution casting route. XRD and HR-TEM analysis confirmed the preparation of a cubic NiO and a hexagonal La2O3 NP with an average crystallite size of 59.85 and 29.13 nm, respectively. Introducing NiO and La2O3 increases the films' amorphous structure. FTIR analysis confirmed the existence of all blend' functional groups and hydrogen bond formation. SEM investigation showed that NiO or La2O3 loading affects the blend surface morphology. A UV-vis-NIR study showed that NiO narrowed the direct bandgap of the blend from 4.1 to 3.3 eV, whereas La2O3 reduced it to 3.4 eV. 1.0 wt% NiO significantly improved the various optical constants of the blend. DMA revealed that storage modulus G ' increased with loading of 1 wt% NiO or La2O3 by 79.3% and 51.0%, respectively while G ' decreased with heating. The dielectric behavior of films is analyzed using several dielectric parameters. The maximum sigma (ac) reported for 1.0 wt% NiO/blend film is 5.8 x 10(-6) (S/cm). The AC conduction mechanism is discussed for all films in the temperature and frequency ranges (298-373 K) and (5 Hz-2 MHz). 1.0 wt%/PVAc/PMMA nanocomposite showed enhanced optical and mechanical properties, making it suitable for architectural, flexible display screens, and photovoltaic cell devices. Moreover, loading NiO and La2O3 improved the dielectric properties of the blend to be used in the semiconductor industry, besides energy storage devices and supercapacitors.