The application of an extrusion modular slit head of a special construction in the in-line extensional viscosity measurements of polymers

摘要

The article has presented the measuring capabilities of the author's modular slit head for the assessment of extensional viscosity (eta(E)). The measurements were carried out using an in-line extruder rheometer. The test material was low-density polyethylene (LDPE). The assessment of the extensional rate ((epsilon) over dot) and extensional viscosity was made based on the analysis of the entrance pressure loss (Delta p(e)), as proposed by Cogswell, the so-called convergent channel method. The unique construction of the head and the flanged measuring module connection system enabled the characteristic of the polyethylene to be determined in the conditions of extensional flow in a convergent and divergent slit channels.