Structural and Optical Features of Sago Starch Polymer Nanocomposites Embedded with Silicon Carbide Nanoparticles

In the present work, biodegradable polymer sago starch based polymer nanocomposite films reinforced with Silicon Carbide (SiC) nanoparticles were synthesized via solution casting method. The resulting polymer nanocomposite films were characterized utilising transmission electron microscopy, X-ray diffraction, UV-VIS-NIR absorption spectroscopy and dielectric spectroscopy. The data obtained from UV-VIS-NIR absorption spectrophotometer was further used to compute optical parameters such as absorption coefficient (α), optical energy gap (E_g) and Urbach’s energy (E_u). Further the transmittance spectra of sago-starch SiC nanocomposite film displayed a sharp decrease in UV region and it decreased from 83.68% to 12.70% at wavelength of 600 nm. Eg of sago-starch film decreased from 4.31 eV to 2.57 eV and E_u increased from 0.66 eV to 1.6 eV with addition of 1 wt% of SiC nanoparticle in sago starch. This is attributed to the additional defects created in HOMO-LUMO gap of polymer matrix. Dielectric spectroscopy results were used to compute dielectric permittivity and dielectric tangent loss. The dielectric permittivity of sago starch increased with addition of SiC nanoparticles while dielectric tangent loss increased at lower frequencies and decreased at higher frequencies and the relaxation peak moved towards the high-frequency side suggesting a decrease in relaxation time.