Structure and Physical Properties of Al₂O₃ Nanofillers Embedded in Poly(Vinyl Alcohol)

Samples of solid poly(vinyl alcohol) (PVA) membrane filled with different concentrations of Al₂O₃ nanofiller were prepared by the casting method. XRD intensity revealed a reduction in the PVA hump intensity with increasing the Al₂O₃ concentration up to x = 0.10 wt%, indicating that the amorphous character increases. Although for higher Al₂O₃ content the membrane crystallinity increased. FTIR spectra revealed distinct absorption bands at approximately 938,845 and 784 cm⁻¹ resulting from the chemical bonding of the Al₂O₃ nanofiller with PVA hydroxyl groups. The DC electrical conductivity was enhanced with the Al₂O₃ nanofiller up to x = 0.10 wt % by three orders of magnitude then it was reduced for higher Al₂O₃ values. This enhancement reflected the creation of charge transfer complexes inside the chains of the PVA network. The reduction in the optical band gap energy with dopant concentration up to x = 0.10 wt% is attributed to defects in the films as well as leads to increased chemical linkage between the polymer chains. These findings confirm that, Al₂O₃ nanofiller were dispersed homogenously through the polymer matrix up to 0.10 wt% uptake. POLYM. COMPOS., 40:E647–E653, 2019. © 2018 Society of Plastics Engineers