title: Rheology of hydroxyethylated starch aqueous systems. Analysis of gel formation.
abstract: This paper reports dynamic viscoelastic and steady shear measurements of aqueous solutions of two commercial hydroxyethyl ethers of potato starch, allowing us to define three different viscoelastic regions, depending on the polymer concentrations. The fluid-like zone (I) corresponds to a homogeneous solution, free of associations between chains, where the linear viscoelastic model can be applied; the fluid-gel transition zone (II) is associated with the rheology of complex systems which possess intermolecular specific interactions; and the gel-like zone (III) involves a network formation giving rise to a gel. The reversibility of the hydrogels was studied by means of steady/dynamic transient experiments allowing breakdown of the gel network and analysis of rehealing. Comparing the elastic moduli of the starch derivative gels leads us to assume that the functionality depends on the capacity to form hydrogen-bonding associations between polymer chains.
authors.affiliation: Polymer Science and Technology Department, University of the Basque Country, Faculty of Chemistry, San Sebastián, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Jauregui
authors.forename: M E
authors.initials: ME
authors.lastname: Muñoz
authors.forename: A
authors.initials: A
authors.lastname: Santamaría
mesh_terms: D004548:Elasticity; D005782:Gels; D006860:Hydrogen Bonding; D006895:Hydroxyethyl Starch Derivatives / Q000737:chemistry*; D046911:Macromolecular Substances; D008956:Models, Chemical; D012212:Rheology; D011198:Solanum tuberosum; D012996:Solutions; D013816:Thermodynamics; D014783:Viscosity; D014867:Water
chemical_list: D005782:Gels; D006895:Hydroxyethyl Starch Derivatives; D046911:Macromolecular Substances; D012996:Solutions; D014867:Water