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Determination of the pressure dependence of polymer melt viscosity using a combination of oscillatory and capillary rheometer
Author(s) -
Raha Sumanta,
Sharma Harindranath,
Senthilmurugan M.,
Bandyopadhyay Sumanda,
Mukhopadhyay Prasanta
Publication year - 2020
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.25307
Subject(s) - rheometer , materials science , rheology , capillary action , molding (decorative) , composite material , viscosity , polycarbonate , shear rate , work (physics) , polymer , mechanical engineering , engineering
For an accurate simulation of a high‐pressure injection molding process by using the CAE software, it is important to understand the pressure sensitivity of a polymer's melt viscosity. The current work describes a method for the determination of the pressure dependence parameter D 3 of the Cross‐WLF model. It uses a combined rheological technique using both dynamic and capillary rheometers. Three grades of polycarbonate homopolymers were studied in this work and their complex viscosities were measured using a dynamic shear rheometer. The dynamic data were used to obtain six out of the seven parameters of the Cross‐WLF, except D 3 . A capillary rheometer fitted with a counter pressure chamber was further used to characterize the pressure dependence of the zero shear viscosity and to determine the D 3 parameter. Finally, the derived parameters were validated by carrying out injection molding with a box tool and comparing the actual pressure profiles with simulation results using the Autodesk® MoldFlow® software. The validation results indicated that actual pressure profiles from the simulation were found to be less than 10% than that of injection molding. POLYM. ENG. SCI., 60:517–523, 2020. © 2019 Society of Plastics Engineers