Preparation and Application of Carboxymethyl Starch

Carboxymethyl starch (CMS) was used as printing thickener, it was synthesized by carboxymethylation reaction with acid-hydrolyzed maize starch and chloroacetic acid(MCA). The optimum conditions of synthesized CMS were as follows: the ratio of nNaOH/nAGU was 3, the ratio of nMCA/nAGU was 1.5:1, etherification temperature was 65°C. The highest degree of substitution(DS) was 0.45. The maximum value of printing viscosity index(PVI) was 0.513, the best water-retention property was 0.2cm and the solid containing rate was 8%. Compared the synthesized CMS with sodium alginate, the results on printing experiments showed the properties of the CMS were almost the same as sodium alginate. Form FT-IR, it was found carboxyl functional group were show at absorption peak of 1604cm-1,1425cm-1 and 1325cm-1, it indicated that the maize starch were substituted.