title: Polyelectrolyte and rheological studies on the polysaccharide welan.
abstract: This paper investigates the polyelectrolyte behaviour of welan in aqueous solution. From conductivity and activity measurements it is demonstrated that a double-helical conformation is adopted irrespective of pH and ionic strength. The intrinsic pK of its carboxylic groups is found to be abnormally low (pKO = 2.2) and no conformational transition was observed during neutralization. The viscometric behaviour was studied as a function of degree of neutralization, polymer concentration, shear rate and ionic strength. The linear relation [eta] = f(Cs-1/2) allows the determination of B, the stiffness parameter from Smidsrød, whose value characterizes a very stiff molecule.
authors.affiliation: Instituto de Fisica e Quimica de Sao Carlos, Brasil.
authors.forename: S
authors.initials: S
authors.lastname: Campana
authors.forename: C
authors.initials: C
authors.lastname: Andrade
authors.forename: M
authors.initials: M
authors.lastname: Milas
authors.forename: M
authors.initials: M
authors.lastname: Rinaudo
mesh_terms: D002236:Carbohydrate Conformation; D004553:Electric Conductivity; D004573:Electrolytes; D006863:Hydrogen-Ion Concentration; D009904:Optical Rotation; D009994:Osmolar Concentration; D011108:Polymers; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D012212:Rheology; D014783:Viscosity
chemical_list: D004573:Electrolytes; D011108:Polymers; D011135:Polysaccharides, Bacterial; C068570:welan