Recent Developments on On-line Rheometry to Monitor the Extrusion Process

On‐line rheometers are generally inserted between extruder and die and generate data that is typically utilized for quality control purposes. However, on‐line rheometers have also the potential to detect changes in structure, morphology, or composition of a given material system, thus assisting materials research and processing optimization, if they can be used along the axis of the extruder or compounder. The authors have previously developed on‐line capillary and rotational/oscillatory rheometers that can be inserted and used at specific locations along the extruder. Since these devices are operated manually, their manipulation may be cumbersome and data may lack reliability. This work presents new versions of these rheometers, with improved functionalities and motorizessd operation. Details on the validation of one of them is also given.