Apparatus and methods for measuring extensional rheological properties of a material
AssigneeCambridge Polymer Group, Inc.
InventorsGavin J.C. Braithwaite, Stephen H. Spiegelberg, Gareth H. McKinley
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Abstract
Apparatus and methods for evaluating the rheological properties of Newtonian and non-Newtonian liquids and melts employs the principle of capillary breakup following rapid stretching of the fluid between two plates.
Claims24
An apparatus for measuring an extensional Theological property of a fluid, the apparatus comprising
- (a) opposed surfaces defining a sample site disposed therebetween and adapted for axial motion to vary the vertical dimension of the sample site;
- (b) a housing about the sample site which permits specification of ambient conditions;
- (c) a light source for directing a light beam at the sample site;
- and
- (d) a light detector for sensing light passing through the sample site.
An apparatus for measuring an extensional rheological property of a fluid, the apparatus comprising
- (a) opposed surfaces defining a sample site disposed therebetween and adapted for axial motion to vary the vertical dimension of the sample site;
- (b) a plunger assembly for varying the vertical dimension of the sample site and for varying the rate of axial movement of at least one of the surfaces;
- (c) a light source for directing a light beam at the sample site;
- and
- (d) a light detector for sensing light passing through the sample site.
An apparatus for measuring an extensional rheological property of a fluid, the apparatus comprising
- (a) opposed surfaces defining a sample site disposed therebetween and adapted for axial motion to vary the vertical dimension of the sample site;
- (b) a light source for directing a light beam at the sample site;
- (c) a light detector for sensing light passing through the sample site;
- and
- (d) a data analysis unit which converts data from the light detector to an extensional rheological property of the fluid sample.
A method for obtaining an extensional Theological property of a fluid sample comprising the steps of:
- (a) stretching the fluid sample to form a fluid filament;
- (b) measuring a time profile of a diameter of the fluid filament;
- and
- (c) analyzing the time profile of the diameter of the fluid filament to obtain an extensional Theological property of the fluid sample, wherein analyzing the time profile comprises converting the time profile to a curve of viscosity versus strain.
Dependencies are inferred from the claim text.