Preparation of mechanical force and citric acid thermoplastic modified corn starch
Corn starch used as raw material to synthesis double-modified thermoplastic starch through the ultra-fine powder and citric acid and glycerol as modifiers. The optimum conditions of double-modified thermoplastic corn starch were researched. Under the reaction time is 60 min, the reaction temperature is 120 ℃, mass ratio of micronization corn starch:citric acid:glycerol was 1:0.4:0.3, obtained that double-modified thermoplastic starch are 0.259 degree of substitution and 0.346 degree of etherification, which are all higher than single-modified starch. Infrared spectroscopy confirmed that the lemon anhydride groups were introduced in starch. The X- diffraction showed the crystalline of double modified starch were dropped.