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Analysis of variance in capillary rheometry
Author(s) -
Moshe A.,
Kazmer D.O.,
Johnston S.P.,
Malloy R.M.,
Kenig S.
Publication year - 2016
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.24318
Subject(s) - compressibility , rheometry , materials science , rheology , instrumentation (computer programming) , thermodynamics , viscosity , capillary action , polymer , equation of state , mechanics , composite material , physics , computer science , operating system
The effect of deformation history (hysteresis) on transient capillary rheometric data was studied compared to conventional assumptions regarding steady state data. The factors studied were: the position instrumentation, the pressure instrumentation, entrance and exit effects, polymer melt compressibility, pressure dependence of the viscosity, and polymer melt viscous heating. Statistical analysis of variance was performed to statistically determine the sources of variance to specific degrees of confidence. The polymer melt compressibility, pressure dependence, and viscous heating were found to be statistically significant contributors of the observed variation at the 95% confidence level; the capillary length and instrumentation were not found to be significant. The results indicate that the transient behavior can vary the modeling of the apparent viscosity in a significant manner such that the model fidelity and model coefficients may vary substantially. Hence, polymer melt compressibility, pressure dependence, and viscous heating should be considered during rheological model fitting to increase model fidelity and predictive accuracy in end‐use. POLYM. ENG. SCI., 56:895–904, 2016. © 2016 Society of Plastics Engineers