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A Rheological Approach to the Analysis of Plastication Influence on Fibers Breakage of LGF‐filled Polypropylene
Author(s) -
Lucchetta Giovanni
Publication year - 2008
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200850301
Subject(s) - rheometer , materials science , polypropylene , rheology , composite material , breakage , shear rate , composite number , glass fiber , viscosity , fiber , shear (geology)
Summary: Long glass fiber‐filled polypropylene composites are widely used in industry because of their low cost and high performance. To investigate the rheological properties of such composites in the molten state an in‐line slit‐die rheometer was developed and mounted on an injection molding machine. The shear viscosity of filled PP determined by the in‐line rheometer was found to strongly depend on the fiber length distribution. In particular, a linear correlation was determined between the viscosity at a constant temperature and shear rate and the average fiber length equation proposed by Huq and Azaiez. The developed model and the in‐line rheometer were then used to assess the effects of the main plastication parameters (i.e. screw rotation speed and backpressure) on fibers damage. The experiments were carried out according to a central composite design and optimal plastication conditions were determined by means of the response surface method.