Effect of nano-SiO₂ on the properties of novel oxidized starch Available to Purchase

In this article, the oxidized starch (OS) with 48·2% degree of oxidation containing 36·2% carboxyl content was prepared by hydrogen peroxide, then nano-SiO₂ was added to obtain OS/SiO₂ composites by solution mixing method. The structure and morphology of OS/SiO₂ were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy and X-ray diffraction (XRD). Thermogravametric analysis, moisture absorption and contact angle (CA) measurements were applied to study their thermal and hydrophobic properties, respectively. XRD analysis showed that the additional nano-SiO₂ had no significant influence on the crystallization of the OS. Moreover, the result of FTIR illustrated that an intermolecular hydrogen bond and a chemical bond C-O-Si were formed between SiO₂ and OS. Therefore, the properties of the OS were improved significantly by nano-SiO₂, especially the thermal stability and hydrophobicity. In addition, when the content of nano-SiO₂ was 3%, the OS/SiO₂ achieved the best properties, its thermal decomposition temperature and CA at 180 s increased from 129·4 to 155·1°C and from 30·7 to 45·4°, respectively, while the moisture absorption rate decreased from 45·3 to 33·1%.