title: Structure-property relationships of carboxymethyl hydroxypropyl guar gum in water and a hyperentanglement parameter.
abstract: The viscoelastic properties of carboxymethyl hydroxypropyl guar gum (CMHPG) in aqueous solution were determined as function of concentration and of molecular weight, using SEC/MALLS/dRI and viscometry. The chain is more rigid as in native guar as was deduced from the molecular parameter in dilute solution. Superstructures are formed in moderately concentrated solutions as is shown from the comparison of steady state shear and small amplitude oscillatory shear (SAOS) experiments. The shear rate dependent viscosity of CMHPG can satisfactorily be described by the Carreau-Yasuda model with the rheological parameters (η0, λ0, n, b) obtained from the evaluation of viscosity data. A quantitative hyperentanglement parameter is introduced to account for the differences in responses in shear and SAOS experiments.
authors.affiliation: Institute for Technical and Macromolecular Chemistry, University of Hamburg, Bundesstraße 45, 20146 Hamburg, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Szopinski
authors.affiliation: Institute for Technical and Macromolecular Chemistry, University of Hamburg, Bundesstraße 45, 20146 Hamburg, Germany.
authors.forename: Werner-Michael
authors.initials: WM
authors.lastname: Kulicke
authors.affiliation: Institute for Technical and Macromolecular Chemistry, University of Hamburg, Bundesstraße 45, 20146 Hamburg, Germany. Electronic address: luinstra@chemie.uni-hamburg.de.
authors.forename: Gerrit A
authors.initials: GA
authors.lastname: Luinstra
mesh_terms: D005685:Galactans / Q000737:chemistry*; D008351:Mannans / Q000737:chemistry*; D008968:Molecular Conformation; D008970:Molecular Weight; D053149:Plant Gums / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*; D012212:Rheology; D012996:Solutions; D013314:Stress, Mechanical; D013329:Structure-Activity Relationship; D014783:Viscosity; D014867:Water / Q000737:chemistry*
chemical_list: D005685:Galactans; D008351:Mannans; D053149:Plant Gums; D011134:Polysaccharides; D012996:Solutions; C469704:carboxymethyl guar gum; C519976:hydroxypropyl guar; D014867:Water
keywords: CMHPG; Guar gum; Hyperentanglement; Shear dependent viscosity; Small amplitude oscillatory shear; Steady state shear