Abstract: The occurrence of grafting copolymerization reaction was proved by analytical means such as FT-IR, X-ray diffraction, SEM, etc. on the obtained composite-modified starch. The physical and chemical properties of the starch were systemically analyzed and described by conventional chemical analysis method. The result of FT-IR analysis showed that there was copolycondensation between acid-hydrolyzed and oxidized starch and acrylamide. X-ray diffraction detected that acid-hydrolysis,oxidation and grafting copolymerization of corn starch mainly occurred in the amorphous area. The result of SEM revealed that the granularity of the modified starch could be intact, but the surface of granule became rough. The results showed that composite-modified starch had the properties such as big sedimentation volume, low pasting-temperature, high hot-pasting stability and low cold-paste viscosity.

Key words: composite-modified starch, grafting copolymer