Influence of silica nanoparticles incorporated with chitosan/polyacrylamide polymer nanocomposites

Nanocomposite films based on chitosan (Cs) and polyacrylamide (PAM) embedded with silica nanoparticles (SiO2 ) were prepared. The films were studied and characterized using different techniques. The X-ray diffraction revealed the presence of the semi-crystalline nature of Cs/PAM blend. No peaks characterizing pure SiO2 were observed due to the masking effect of the Cs/PAM blend matrix resulting of the low amount of SiO2 . The main characteristic IR-bands to the vibrational groups for Cs/PAM were observed. No changes in the position of IR bands were seen after incorporation of SiO2 nanoparticles. The UV-vis spectra showed an absorption band at 253 nm with a sharp absorption edge which indicates the semi-crystalline nature of Cs/PAM matrices. The spectra optical parameters were measured and characterized as a function of photon energy. The value of optical energy gap (E g ) was estimated using indirect transition model and explained due to local cross-linking in the amorphous regions of Cs/PAM. The plot of dielectric loss and dielectric constant epsilon' and epsilon '' with the frequency was gradually decreased with the increase of the frequency and reaches to constant values at higher frequencies due to polarization effects. The plot of real impedance (Z') with imaginary impedance Z '' gives a perfect semicircle correlated to Debye behavior. (C) 2019 The Authors. Published by Elsevier B.V.