Rheological properties of cellulose hydrogels prepared from Cladophora cellulose powder

The rheological properties of cellulose hydrogels prepared from cellulose powder of algal origin (Cladophora sp. green algae) were investigated and compared to a commercially available dispersive cellulose grade (Avicel RC-591). The rheological properties of cellulose hydrogels were investigated using a controlled rate instrument of couette type in the dynamic oscillation mode. Cladophora cellulose powder was dispersed in carboxymethylcellulose solutions of different concentrations. It was found that Cladophora cellulose forms gel structures at cellulose concentrations as low as 0.2% (w/v), whereas the lower threshold for the commercially available analog is around 1.5% (w/v) solids contents. Carboxymethylcellulose, even though useful in aiding the dispersion, has a negative effect on the viscoelastic properties of Cladophora cellulose when used in high concentrations. Cladophora cellulose powder could be a useful alternative to commercially available dispersible cellulose grades when very low quantities of stabilizing agents are required. (c) 2006 Elsevier Ltd. All rights reserved.