Abstract
Chemically prepared cobalt oxide nanoparticles (NPs) were added to biodegradable carboxymethyl cellulose (CMC) (20%)/polyvinyl alcohol (PVA) (80%) blend films. The structural properties of these films were investigated by X-ray diffraction, Fourier transformation infrared spectroscopy (FTIR) and differential thermal analysis (DTA). Co3O4/(CMC + PVA) films show a semi-crystalline structure and the degree of crystallinity decreases with adding Co3O4 NPs. FTIR confirms the good interaction between the blend chains and Co3O4 NPs. The melting temperature Tm for CMC/PVA is about 212 °C then decreased with increasing Co3O4 content, due to some decrease in the ordered association of the blend which results in a decrease in the blend crystallinity. Positron annihilation lifetime spectroscopy (PALS) measurements were carried out with a conventional fast–fast coincidence spectrometer. It was found that ortho-positronium lifetime τ 3 and free volume Vf increase while o-Ps intensity I3 still constant as Co3O4 concentration increases. This is because adding Co3O4 NPs encourages the formation of o-Ps. The swelling ratio SR% as a function of Co3O4 concentration was also studied and its value increases with Co3O4 addition. The optical study illustrated the decrease of the transmittance T of the films from 87 to 35.5% with increasing Co3O4 content from 0 to 0.9 wt%. Also, both the direct and indirect optical band gaps of the films red-shifted from 4.05 to 3.75 eV and 3.3 to 2.75 eV, respectively. The influence of Co3O4 on the refractive index of the films is also reported.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call