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Experimental studies on the biaxial extensional viscosity of polypropylene
Author(s) -
Hoover Kenneth C.,
Tock Richard W.
Publication year - 1976
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.760160204
Subject(s) - extensional viscosity , materials science , extensional definition , polypropylene , composite material , rheology , viscosity , blow molding , spinning , molding (decorative) , deformation (meteorology) , shear viscosity , geology , paleontology , mold , tectonics
For fabrication processes such as blow molding, vacuum forming, film blowing and fiber spinning, extensional flow is the dominate mode of melt deformation. Under these conditions, extensional viscosity is a significant rheological property. Thus, the biaxial extensional viscosity was measured for several samples of polypropylene. A technique based on the bubble inflation method of Denson and Gallo was used. Experimental values of biaxial extensional viscosities ranging from 10 14 to 10 10 poise as a function of strain rate, 10 −5 to 10 −2 reciprocal seconds, were obtained at 25°C. The technique used was critiqued and found to be useful in characterizing unoriented and biaxially oriented films, Uniaxially oriented films gave unsatisfactory results. It may be possible to use this testing method to assist in materials selection decisions.