Retrogradation Behavior of Cassava Starch Modified by Different Surface Properties Nano‐Silica under Combined Actions of Tensile and Ultrasound

The combined actions of tensile and ultrasound on the melting enthalpy, retrogradation kinetics, spherical morphology, crystal structure, thermal stability, hydrophilicity, and molecular chain of thermoplastic cassava starch (TPS) containing different surface properties nano‐silica (SiO 2 ) are investigated. The result indicates that the melting enthalpy of TPS/SiO 2 composite and the retrogradation rate increases under combined actions of tensile and ultrasound, and the sample containing hydrophobic nano‐SiO 2 is greater than that of hydrophilic nano‐SiO 2 . The spherulites of TPS/SiO 2 composite become obvious, and the contact angle increases; however, the thermal degradation temperature decreases. Under combined actions of tensile and ultrasound, the aggregation of nano‐SiO 2 particles in the matrix reduces and the dispersion become uniform. TPS/SiO 2 composite presents A+V type crystal structure, and V‐type crystal increases after the combined actions of tensile and ultrasound. The storage modulus, loss modulus, and glass transition temperature of TPS/SiO 2 composite increase, and the sample containing hydrophobic nano‐SiO 2 is higher than that of sample containing hydrophilic nano‐SiO 2 .