DILUTE-SOLUTION BEHAVIOR OF PARTIALLY HYDROLYZED POLYACRYLAMIDE

Flow behaviour of partially hydrolysed polyacrylamide (PHPA) is studie d in aqueous and in ethylene glycol-water, dimethyl formamide-water bi nary solvents. At low concentrations (100-1000 ppm)reduced viscosity ( eta(sp)/c) increases with decrease of concentration of the polymer. It obeys Fuoss plot, i.c., c/eta(np) linearly depends on the square root of concentration (root c). However, in presence of Na+ reduced viscos ity (eta(sp)/c) of PHPA polymer is a linear function of concentration. The solution viscosity exhibits a substantial shear thinning effect i n all the three solvents. Shear thinning behaviour diminishes on incre ase of salt concentration producing Newtonian behaviour (1-40 s(-1)). Dilute solution of PHPA degrades when stored for a prolonged period. T his aging behaviour can be prevented by using 300 ppm of antimicrobial agent such as monoethanolamine, diethanolamine and triethanolamine.