Studies on structural, optical and mechanical properties of MWCNTs and ZnO nanoparticles doped PVA nanocomposites

This paper presents a novel class of multiwalled carbon nanotubes (MWCNTs) and zinc oxide (ZnO) doped polyvinyl alcohol (PVA) nanocomposites prepared using coagulation and solvent casting method. The dopant, ZnO nanoparticles, was prepared using precipitation method, and another dopant, MWCNTs, was treated with H2SO4 and HNO3 taken in 3:1 volume ratio to create carboxylated MWCNTs. Furthermore, prepared ZnO and treated MWCNTs were doped into PVA matrix to prepare PVA nanocomposites by solvent casting technique. The Fourier transform infrared (FTIR) spectra detect the irregular shift in the bands of doped PVA nanocomposites indicating the presence of intra/intermolecular hydrogen bonding creating the interaction between the nanoparticles and neighboring OH group of PVA. Crystallinity of the prepared nanocomposites films was investigated using XRD technique, which explores the average particle size of the embedded nanoparticles and explains the complex formation and variation in crystallinity of the nanocomposites due to interaction of dopants. The decrease in optical energy band gap of nanocomposite films and the information of Urbach energy (E-u) were assessed by UV/vis spectroscopy. By using a universal testing machine, the mechanical properties of doped polymer films found escalation for doping percentage concentration x=7.5 wt%. The phase homogeneity, film morphology, and chemical configuration of the nanocomposites were inspected using atomic force microscope, scanning electron microscopy and energy-dispersive X-ray spectroscopy, respectively.