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Capillary rheometry of raw elastomers, butadiene‐acrylonitrile copolymers
Author(s) -
Nakajima Nobuyuki,
Collins Edward A.
Publication year - 1974
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760140209
Subject(s) - die swell , rheometry , materials science , capillary action , composite material , shear rate , shear stress , ultimate tensile strength , strain rate , elastomer , slipping , rheology , plastics extrusion , structural engineering , engineering
Capillary rheometry of four butadiene‐acrylonitrile copolymer raw elastomers was performed at 125°C over a wide shear rate range. The data were corrected for the effect of pressure on viscosity, for pressure loss in the barrel and at the capillary entrance, for the non‐Newtonian velocity profile (Rabinowitsch correction) and for the temperature rise at high shear rates (shear heating). The corrected results were compared to the tensile stress strain data obtained at comparable strain rates. The agreement between the capillary flow data and the tensile stress strain data was quite good, however, some slight systematic differences were noted. The difference was interpreted as the consequence of slipping of materials at the capillary wall. Die swell values were measured and presented as functions of shear rate and capillary length. Extrudate distortions are described.