Starch Phosphate Hydrogels. Part II: Rheological Characterization and Water Retention

Hydrogels with different mechanical properties were synthesized by cross-linking monostarch monophosphates (MSMP) with various di- and tricarboxylic acids (succinic, glutaric, adipic, citric, and maleic acid) by using a semi-dry method. For a physical characterization water retention and rheological parameters (dynamic viscosity η*, storage and loss moduli G' and G") of the hydrogels were determined. Rheomechanical measurements revealed the viscoelasticity and mechanical sturdiness of the gels. Due to their special physical qualities MSMP hydrogels are not only suitable for different industrial applications but also have a big potential to be used as water storing soil amendments improving the efficiency of irrigation especially in arid regions. In order to investigate the suitability of MSMP hydrogels as water storing soil amendments the water retention curves of a sandy soil treated with different amounts of a selected starch phosphate hydrogel were determined.