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Melt rheology of semirigid PVC compounds
Author(s) -
Tu ChingFang
Publication year - 1980
Publication title -
journal of vinyl technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 35
eISSN - 1548-0585
pISSN - 0193-7197
DOI - 10.1002/vnl.730020409
Subject(s) - shear rate , rheology , lubricant , materials science , rheometer , shear (geology) , discontinuity (linguistics) , composite material , viscosity , thermodynamics , apparent viscosity , shear viscosity , mechanics , mathematics , mathematical analysis , physics
This paper describes a statistical experiment on the melt behavior of semirigid PVC compounds using a capillary rheometer. Three formulating variables, viz., PVC resin inherent viscosity, internal lubricant concentration, and external lubricant concentration, and two processing variables, viz., shear rate and temperature, were examined. The dependent variables tested were melt viscosity and critical shear rate. The regression equations relating the formulating variables with dependent variables were obtained at various temperatures. Melt distortion free formulations can thus be determined from the contour plots of the dependent variables. Depending on formulation and processing conditions, a discontinuity in the flow curves is observed Melt irregularity of extrudates was observed to occur not only at very high shear rates but also at very low shear rates and at the discontinuity of flow curve.