Preparation and property investigation of crosslinked alginate/silicon dioxide nanocomposite films

Crosslinked nanocomposite films of sodium alginate (SA) and silicon dioxide (SiO₂) with different SiO₂ loading values were prepared by in situ synthesis. Biocomposite films were produced by solution casting and solvent evaporation with glycerol as the plasticizer and calcium chloride as the crosslinking agent. The effects of the addition of nano silicon dioxide (nano‐SiO₂) in SA on the microstructural, physical, mechanical, and optical properties of the nanocomposite films were characterized. The results show that nano‐SiO₂ was dispersed homogeneously in the SA matrix; it thereby formed a strong interfacial interaction between the nano‐SiO₂ particles and the matrix. The transparency of the bionanocomposite films was enhanced. Thermogravimetric analysis also revealed that nano‐SiO₂ improved the thermal stability of the SA films. The incorporation of SiO₂ further reduced the water vapor permeability and swelling degree and significantly increased the tensile strength and elongation, which are parameters important for packaging industries. Finally, the lower light transmission of UV light from 200 to 250 nm indicated that SA/SiO₂ nanocomposite films could potentially be used to prevent lipid damage by UV light in food conservation. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43489.