I am currently using an extruder with a capillary die for testing polymer samples, what additional information will I get from a capillary rheometer?
The capillary rheometer is designed for accurate and precise temperature and speed control, and is fitted with high accuracy pressure transducers. An extruder, by its very nature, is not a well controlled processor and can only be used to generate crude viscosity data, due to temperature control limitations, inconsistent flow to the die and excessive shear heating. Furthermore, the results can vary with the choice of screw and are subject to the problems of consistently feeding the extruder, which is not a trivial matter.
