Can I get viscoelastic information from the capillary rheometer?
The rotational rheometer is generally better suited for the determination of linear viscoelastic properties. In capillary rheometry, the most obvious elastic effect is post-extrusion swelling, commonly referred to as die swell or extrudate swell. It is interpreted as evidence of recoverable strain, but for most practical purposes, it is the comparative swell ratio that is of importance. The measurement is made using a laser micrometer that is mounted just below the die exit.
