Rheological behaviour of solutions of poly(2-hydroxyethyl methacrylamide) in glycerine

The theological behaviour of dilute and semidilute solutions of poly(2-hydr oxyethyl methacrylamide) in glycerine is described, emphasising the study o f the variation of both the zero shear rate viscosity, eta (0), and the ste ady-state compliance function, J(e)(0), with concentration. Shear rate fiel ds, above a critical value, may promote molecular tight 'structures' that e nhance the viscosity of the semidilute solutions and, as a result, these sy stems exhibit shear-thickening behaviour. However, the dilute solutions dis play shear-thinning behaviour and obey the Cox-Merz rule. The flow transien ts appearing after either application of a constant shear rate or cessation of Row were studied for semidilute solutions. The shear-thickening behavio ur of these solutions is interpreted in terms of the formation of hydrogen bonds between the acrylamide groups and the carbonyl groups of different ch ains. (C) 2001 Elsevier Science Ltd. All rights reserved.