Effect of SiO2 nanoparticle on the physical and chemical properties of eco-friendly agar/sodium alginate nanocomposite film

Agar/sodium alginate (AG/SA) nanocomposite films were prepared using solution casting method in presence of various concentrations of nano-SiO2 (2.5, 5, 7.5, and 10 wt%). The effect of nano-SiO2 concentration on the nanocomposite film was investigated. The result of Fourier transform infrared (FTIR) illustrated the formation of hydrogen bonding between nano-SiO2 and polysaccharide. As nano-SiO2 concentration rose from 0 to 10 wt%, the tensile strength and elongation at break all increased up to maximum, respectively. The tensile strength and elongation at break of film containing 10 wt% nano-SiO2 increased by 65.29% and 60.38% respectively when compared to those of film prepared without nano-SiO2. The reason for enhancing in tensile strength might be related to the formation of molecular interaction. The film containing 2.5 wt% nano-SiO2 had maximum water contact angle and minimum water vapor permeability among those of all films prepared in this work. However, the film containing 10 wt% nano-SiO2 had minimum swelling degree and water solubility, further demonstrating the formation of strong interaction. The addition of nano-SiO2 improved the properties of film against UV light and thermal stability. Overall, the addition of nano-SiO2 enhanced the mechanical properties, water resistance and thermal stability of polysaccharide film.