Slit-die Rheometry and its Potential in Polymer Melt Rheology
Sprache des Titels:
Englisch
Original Kurzfassung:
Slit die rheometry is known since the early 70th of the last century
aiming at improving pressure drop measurement, widening the shear rate
range to be covered and offering new possibilities to characterize
compounds with complex rheological behavior such as wall slipping PVC
and rubber compounds. Adapting slit die systems to processing machines
in injection molding and extrusion offers new possibilities in
rheological characterization at conditions close to processing.
In this contribution the application of slit-die rheometers for
thermoplastics and uncurable rubbers compounds will be discussed in
detail from first systems up to special machine rheometers such as
by-pass extrusion rheometers and injection molding machine rheometers.
Advantages and disadvantages as well as new possibilities in
characterizing pressure dependency of viscosity will be pointed out.
Rheological measurements will be presented for polypropylene, wall
slipping PVC, wood plastic compounds and rubber compounds containing no
curatives. A special injection mold for slit die rheometry offers the
possibility to widen the shear rate range up to 106 s-1 and to measure
the pressure dependency of viscosity up to pressure levels of approx.
600 bars. The rheological evaluation of measured values and the
approximation of true viscosity curves take into account temperature
rise due to shearing according to a method of Aggassant.
Sprache der Kurzfassung:
Englisch
Englischer Titel:
Slit-die Rheometry and its Potential in Polymer Melt Rheology
Englische Kurzfassung:
Slit die rheometry is known since the early 70th of the last century
aiming at improving pressure drop measurement, widening the shear rate
range to be covered and offering new possibilities to characterize
compounds with complex rheological behavior such as wall slipping PVC
and rubber compounds. Adapting slit die systems to processing machines
in injection molding and extrusion offers new possibilities in
rheological characterization at conditions close to processing.
In this contribution the application of slit-die rheometers for
thermoplastics and uncurable rubbers compounds will be discussed in
detail from first systems up to special machine rheometers such as
by-pass extrusion rheometers and injection molding machine rheometers.
Advantages and disadvantages as well as new possibilities in
characterizing pressure dependency of viscosity will be pointed out.
Rheological measurements will be presented for polypropylene, wall
slipping PVC, wood plastic compounds and rubber compounds containing no
curatives. A special injection mold for slit die rheometry offers the
possibility to widen the shear rate range up to 106 s-1 and to measure
the pressure dependency of viscosity up to pressure levels of approx.
600 bars. The rheological evaluation of measured values and the
approximation of true viscosity curves take into account temperature
rise due to shearing according to a method of Aggassant.