The influence of polymer adsorption, and fiber composition, on the rheology of aqueous suspensions of aspen, cotton, and corn stover pulps

Abstract The mechanisms governing the ability of water-soluble polymers (WSP) to alter the rheological properties of lignocellulosic biomass to achieve processing advantages are investigated. Lignocellulosic fiber surface chemistry is found to be an important factor in the efficacy of WSPs as rheological modifiers, and a strong correlation between the amount of adsorbed polymer at fiber surfaces and the yield stress of the fiber suspension indicate that adsorption of polymer is important for rheological modification. Three fiber suspensions of varying physical chemistry were produced from Aspen wood chips, and a number of additional fiber suspensions with chemically functionalized surfaces were generated from cellulose pulp. Polymer adsorption and suspension rheology are found to correlate in every case examined, but the amount of adsorbed polymer alone cannot be used to predict the efficacy of a WSP as a rheological modifier, suggesting that there are contributions from additional variables such as adsorbed-polymer conformation.