Synthesis and Properties of Novel Hydrogels from Cross-linked Starch Phosphates

Starch based stable hydrogels providing high swelling and water storing capacity are not only of certain interest for the cosmetics and hygiene industry but also have the potential to become an effective tool in combating desertification and supporting cultivation in many regions of the world. It has been found that strong water adsorbing covalent networks with free swelling capacity (FSC) of up to 190 g water/g hydrogel can be obtained by cross‐linking low‐substituted mono‐starch phosphates (MSP) in a semi‐dry process with di‐ and tricarboxylic acids such as succinic acid (SA), adipic acid (AA) or citric acid (CA). The linear behaviour over a wide frequency range of the rheological parameters G′ and G″ which were determined by using a shearing disc viscosimeter clearly reveal that the cross‐linked starch phosphates are stable hydrogels having stronger elastic than viscous properties.