Synthesis and aggregates of cellulose-based hydrophobically associating polymer

A novel cellulose-based hydrophobically associating water-soluble polymer-cellulose octaonate sulfate (COS) was synthesized in this paper. The basic physico-chemical properties such as surface tension and the critical aggregation concentration (cac) were measured by the conventional Wilhelmy plate method. The obtained cac value was compared with environmental scanning electron microscopy (ESEM) and Rheology data. All these results indicated that cac of this amphiphilic polymer was between the range 0.04 and 0.2 wt% and the corresponding surface tension was around 55 mN/m. The conformation of aggregates and size of particles in aqueous solution were carefully investigated by ESEM and dynamic laser scattering (DLS) measurements. When the concentration is around 0.04 wt%, loose aggregates are formed; around 0.5 wt%, network structure formed. DLS results indicated that average size of particle was increased from 54.7 nm to 73 nm and finally to 168.1 nm with the increase of concentration from 0.04% to 0.1% and even to 0.2%. These results suggested that almost all of micelles in aqueous solution aggregated at the experimental concentration range 0.04–0.5 wt%. Rheological properties of this polymer were similar to hydrophobically associating polymers’ (HMP). As the shear rate increased, the solution passed through a shear-thickening region before exhibiting a sharp decrease in viscosity, eventually exhibited Newtonian behavior.