title: Small strain deformation measurements of konjac glucomannan solutions and the influence of borate cross-linking.
abstract: The dynamic rheology of aqueous solutions of konjac glucomannan has been evaluated over a range of concentrations up to 2.35%, and the effect of borate cross-linking of such solutions evaluated in the range 0.02-40 mM borate. In preliminary work, conventional parallel plate geometries were employed and in situ cross-linking was investigated. For borate cross-linked samples a superior method, however, was found to be measurement of pre-formed cores of cross-linked polymer into which a four-bladed vane geometry was introduced. In order to compare with other associating polymer systems, rheological data were analysed by defining plateau moduli, corresponding relaxation times and zero shear viscosities and the scaling behaviour of these parameters with polymer and cross-linker concentrations was established. Maxwell fits and time-concentration superposition procedures were investigated. The rheological properties of the cross-linked polymer were shown to be the result of both increased network connectivity and retarded network dynamics.
authors.affiliation: Centre for Water Soluble Polymers, Glyndwr University, Plas Coch, Mold Road, Wrexham LL11 2AW, UK. ratcliffei@glyndwr.ac.uk
authors.forename: Ian
authors.initials: I
authors.lastname: Ratcliffe
authors.forename: Peter A
authors.initials: PA
authors.lastname: Williams
authors.forename: Robert J
authors.initials: RJ
authors.lastname: English
authors.forename: John
authors.initials: J
authors.lastname: Meadows
mesh_terms: D001881:Borates / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry*; D008351:Mannans / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D012212:Rheology; D012996:Solutions; D014783:Viscosity
chemical_list: D001881:Borates; D003432:Cross-Linking Reagents; D008351:Mannans; D011108:Polymers; D012996:Solutions; C022901:(1-6)-alpha-glucomannan