Measurement of extensional elasticity of weakly-elastic liquids

Abstract

The focus of rheology is generally on shearing because shear is the dominant mode of deformation in most transport processes. At the same time, there are processes in which extension is the dominant motion, and then the rheological challenge is to characterize fluid resistance to extensional deformation. While extensional motion is important in polymer processes such as film blowing and extrusion, this work focuses on extensional motion of solutions and suspensions primarily because extensional motion of these fluids is all printing and coating processes, including roll coating and inkjet printing. In this paper, the state of extensional rheometry is briefly reviewed and then a new technique to measure extensional flow resistance is introduced.

Keywords

extensional rheometry / fluid filament / fluid bridge / spinnability / filament breakup / breaking length / weak elasticity / filancemeter / polymer solutions / drag reduction

References

[1] BatchelorG. K.. The stress generated in a non-dilute suspension of elongated particles by pure straining motion[J]. J Fluid Mechanics, 1970, 46: 813-829

[2] TirtaatmadjaV., SridharT.. A filament stretching device for measurement of extensional viscosity[J]. J Rheol, 1993, 37: 1081-1102

[3] ArnouldJ.P., ZahmJ.M., PottierG., DuvivierC., PuchelleE.. A new apparatus for measuring the thread-forming property (spinability) of biological fluids. Biorheology, 1984, 23(s1): 123-126

[4] RubinB. K.. An in vitro comparison of the mucoactive properties of guaifenesin, lodinated glycerol, surfactant, and albuterol[J]. Chest, 1999, 116: 195-200