Premium
Influence of rheological properties on the sagging of polypropylene and abs sheet for thermoforming applications
Author(s) -
Lau H. C.,
Bhattacharya S. N.,
Field G. J.
Publication year - 2000
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.11286
Subject(s) - thermoforming , materials science , composite material , rheology , polypropylene , acrylonitrile butadiene styrene , polymer , viscosity , shear rate , elastic modulus , viscoelasticity
The isothermal sagging resistance of different grades of conventional and a high melt strength (HMS) PP has been correlated with the rheological characteristics of the polymers, such as dynamic shear properties, melt strength, and zero shear viscosity. A thermoforming grade of acrylonitrile‐butadiene‐styrene (ABS) was used as a reference material. At 190°C, ABS had the highest viscosity and elastic modulus in the frequency range measured, showing that this polymer is highly elastic. HMS PP had a greater shear thinning behavior than conventional PP because of its broader molecular weight distribution. The tan δ of the polymers showed that conventional PP had a higher tendency to flow than HMS PP and ABS when heated above 172°C. This was confirmed with sagging experiments performed in an air circulating oven, where the rate of sagging decreased as the melt strength and the zero shear viscosity of the polymer increased.