Summary: Starch based stable hydrogels providing high swelling and water storing capacity are not... more Summary: 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.
Starch-based hydrogels were synthesized by cross-linking monostarch monophosphates (MSMP) with di... more Starch-based hydrogels were synthesized by cross-linking monostarch monophosphates (MSMP) with different di- and tricarboxylic acids such as succinic, adipic or citric acid. Phosphorylation of starch was performed in a semi-dry process using a mixture of primary and secondary sodium phosphates. The phosphorus content and degree of substitution of phosphate groups (DSP) of the resulting MSMP were determined using a photometric method. For structural characterization of starch phosphates 31P NMR was used. Investigations showed that MSMP hydrogels were strong water absorbing polymer networks with a free swelling capacity (FSC) of up to 185 g water / g dry hydrogel.
Hydrogels with different mechanical properties were synthesized by cross-linking monostarch monop... more 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.
Summary: Starch based stable hydrogels providing high swelling and water storing capacity are not... more Summary: 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.
Starch-based hydrogels were synthesized by cross-linking monostarch monophosphates (MSMP) with di... more Starch-based hydrogels were synthesized by cross-linking monostarch monophosphates (MSMP) with different di- and tricarboxylic acids such as succinic, adipic or citric acid. Phosphorylation of starch was performed in a semi-dry process using a mixture of primary and secondary sodium phosphates. The phosphorus content and degree of substitution of phosphate groups (DSP) of the resulting MSMP were determined using a photometric method. For structural characterization of starch phosphates 31P NMR was used. Investigations showed that MSMP hydrogels were strong water absorbing polymer networks with a free swelling capacity (FSC) of up to 185 g water / g dry hydrogel.
Hydrogels with different mechanical properties were synthesized by cross-linking monostarch monop... more 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.
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