INFLUENCE OF TEMPERATURE AND POLYMER CONCENTRATION ON RHEOLOGICAL PROPERTIES OF RHAMSAN
Urška Florjanèiè and Miha Žumer
Faculty of Chemistry and Chemical Technology, Department of Chemical Engineering, University of Ljubljana, Aškerèeva 5, SI 1001 Ljubljana, Slovenia
Microbial polysaccharide rhamsan imparts high solution viscosity at very low polysaccharide concentration and forms weak gels. The rheological behaviour, in particular the viscoelastic properties of aqueous rhamsan systems were investigated by using controlled stress rheometer HAAKE RS150, equipped with two sensor systems: cone-plate and double cone. The effects of temperature and polymer concentration on the rheological properties of rhamsan systems were examined under steady shear and oscillatory conditions. Variation in polymer concentration and environmental conditions results in changes of the consistency and the elastic response, which is very important for practical use. The viscoelastic data were described by applying the generalized Maxwell model.