The effect of nano‐SiO₂ on the physicochemical and structural properties of gelatin‐polyvinyl alcohol composite films

Abstract

Abstract This study investigated the effects of nano‐silicon dioxide (nano‐SiO 2 ) (0%, 0.5%, 1%, and 1.5%) and the ratio of PVA/gelatin (1:1 and 2:1) on the physicochemical and structural properties of gelatin/polyvinyl alcohol composite films. The results showed that the highest value of tensile strength (18.05 MPa) was found for a PVA/gelatin ratio of 2:1 and 1% nano‐SiO 2 (P2:G1‐1%). The films’ elongation at break value increased with increases in the nano‐SiO 2 and PVA content, while their water solubility decreased with the addition of nano‐SiO 2 . Their water vapor permeability decreased with 1% nano‐SiO 2 , and the lowest value for water vapor permeability was with P2:G1‐1%. Fourier transform infrared and differential scanning calorimetry results showed that appropriate interaction between both polymers and nano‐SiO 2 was found with P2:G1‐1%. Scanning electron microscopy illustrated a compact structure and good compatibility of nano‐SiO2 with gelatin in P1:G1‐1% film. X‐ray diffraction results showed that the crystallization peak intensity of P2:G1‐1% was higher than that of P1:G1‐1% nanocomposite films. Overall, the results indicated that the concentration of 1% of nano‐SiO 2 in P2:G1 films significantly improved the films’ physicochemical and structural properties. These results suggest that they could be useful as food‐packaging materials to maintain food quality. Practical application Gelatin films possess properties that make them useful in packaging, such as water vapor resistance and low values for mechanical properties. PVA as a synthetic polymer, have good tensile strength asz and biodegradability along with high numbers of hydrophilic groups. PVA has also been used in many biomaterial applications. Some advantages of nanomaterials such as silica nanoparticle are high mechanical strength, biocompatibility, and biodegradability. In the present study, nano‐SiO 2 was used in films blended from PVA and gelatin. The improved physicochemical and structural properties achieved through the use of nano‐SiO 2 could make the films more effective as food packaging.