Preparation and Properties of Oxidized Starch

The corn starch was modified into oxidized starch containing both carboxyl and aldehyde groups by chemical method, which provided a new clean tanning agent for leather industry. The original oxidized starch containing large number carboxyl groups was obtained by orthogonal experiments and the optimal conditions were as follows: pH 9.0, time 4h, temperature 45℃ and amount of H 2O 2 was 30% of corn starch. Then the oxidized starch containing large number aldehyde groups was obtained and the optimal conditions were as follows: pH 1.2, time 4h,temperature 40℃ and n(NaIO 4)∶n(oxidized starch with carboxyl group) was 1∶1.2. The content of carboxyl group in the original oxidized starch was 0.75%, which was measured by conductance titration method. And the aldehyde group content of the oxidized starch was 0.83%, which was measured by ultraviolet (UV) spectra. And weigh average molecular weight of original oxidized starch and oxidized starch was 7238.70 and 2915.44 respectively, which was determined by high performance liquid chromatogram (HPLC).