Complexes of Starch with Dioic Acids

Attempts are presented for the preparation of complexes of starch with a series of dioic acids (oxalic, malonic, succinic, glutaric and adipic). The complexes are isolated and characterized by potentiometric titration, powder X‐ray diffraction, characteristics of gelation and differential scanning calorimetry. These complexes contain dioic acids on the level of 1−3g per 1g of starch. Oxalic acid forms a surface complex with crosslinking involving both its carboxylic groups. Malonic acid forms surface complex with involvement of only one of its carboxylic groups and all three succinic, glutaric and adipic acids form inclusion complexes.