Elastic and viscous properties of dilute solutions of polymethyl methacrylate in organic liquids

Abstract

An investigation has been made into the variability and interconnections of three constants-a viscosity coefficient 70, a stress relaxation time A1 and a rate of strain relaxation time A2-which serve to characterize the behaviour of a dilute solution of highly polymerized methyl methacrylate in a simple shearing motion at small rates of strain. The principal experimental results, which refer to solutions containing between 1 and 10 % of polymer in toluene, pyridine, cyclohexanone and n-butyl acetate, were derived from observations with a coaxial-cylinder elastoviscometer at temperatures in the range 15" to 45" C . No large deviations of A2 from the value 0.015 sec were observed, but both 90 and A1 varied with polymer concentration, the nature of the solvent, and temperature ; values of A1 between 0.02 and 0.2 sec were found, and these corresponded with values of 70 between 1 and 20 poises. It is deduced that, under the experimental conditions, relaxation of shear stress and of rate of strain were effected by different processes, and this conclusion is thought to be consistent with current " molecular " theories of rubber-like elasticity and of the constitution, and viscous flow, of solutions of linear polymers.

Double-diffusive convection in a viscoelastic fluid

“…For example, Bhatia and Steiner [14] have considered the effect of a uniform rotation on the thermal instability of a Maxwell fluid and have found that rotation has a destabilizing effect in contrast to the stabilizing effect on Newtonian fluid. Experimental demonstration by Toms and Strawbridge [15] has revealed that a dilute solution of methyl methacrylate in n-butyl acetate agrees well with the theoretical model of the Oldroyd fluid. The thermal instability of an Oldroydian viscoelastic fluid has been considered in the presence of rotation (Eltayeb [16], Sharma [17]) and magnetic field (Sharma [18]).…”

Rayleigh-Taylor Instability of Viscous-Viscoelastic Fluids in Presence of Suspended Particles Through Porous Medium

“…Oldroyd [9] proposed a theoretical model for a class of viscoelastic fluids. An experimental demonstration by Toms and Strawbridge [10] revealed that a dilute solution of methyl methacrylate in n-butyl acetate agrees well with the theoretical model of Oldroyd.…”

Stability of Two Superposed Viscoelastic (Walters B') Fluid-Particle Mixtures in Porous Medium

“…Oldroyd [6] proposed a theoretical model for a class of viscoelastic fluids. An experimental demonstration by Tom and Strawbridge [7] reveals that a dilute solution of methyl methacrylate in nbutyl acetate agrees well with the theoretical model of the Oldroyd fluid. Slattery [8] has studied the flow of viscoelastic fluids through a porous medium.…”