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Viscosity, modulus, and die swell of glass bead filled polystyrene‐acrylonitrile copolymer
Author(s) -
Agarwal Pawan K.,
Bagley Edward B.,
Hill Christopher T.
Publication year - 1978
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.760180408
Subject(s) - materials science , shear rate , die swell , composite material , rheometer , shear modulus , shear stress , shear (geology) , polystyrene , critical resolved shear stress , extrusion , viscosity , rheology , polymer
Flow curves were obtained at 190°C over the shear rate range 0.1 to 100 sec −1 for polystyrene‐acrylonitrile copolymer containing up to 36 percent by volume glass beads, using a capillary extrusion rheometer. The addition of glass beads always increased shear stress and viscosity at a given shear rate, with the increase being more pronounced at low shear rates. The addition of glass beads decreased die swell, which also depended on shear‐stress and capillary length‐to‐radius ratio. At low shear rates a lower limiting value of die swell ratio of about 1.1 was achieved. Values of recoverable shear derived from end correction data by the technique of Philippoff and Gaskins and from die‐swell data by the method of Bagley and Duffey are compared. A fairly good agreement was found for low concentration blends at low shear, However, the values differed by a factor of up to 3 at higher shear stresses. In all cases, recoverable shear was found to increase with shear stress at a fixed filler loading and to decrease with increased filler loading at a fixed shear stress. Values of shear modulus calculated from the recoverable shear measurements decreased rapidly with increasing shear stress.