ガラス繊維を混入したポリプロピレン溶融体のレオロジー的研究

抄録

The basic rheological properties of glass fiber filled polypropylene melts were studied by shear flow and elongational flow methods. Shear viscosity, the first and second normal stress differences in shear flow, elongational viscosity, die ends pressure losses, and extrudate die swell are discussed.
Glass fibers increase shear viscosity and normal stresses, with the greater increase being for the latter property. This effect can be shown clearly by plotting φ₁/2η for shear rate γ, where φ₁ is the first normal stress coefficient and η shear viscosity. The presence of glass fibers substantially increases elongational viscosity χ at low elongational rates but χ decreases rapidly at high deformation rates. The ratio of die ends pressure losses to shear stress, Δp_ends/(σ₁₂)_w, i.e., the Weissenberg number., is significantly increased with increasing the contents of glass fibers, but the extrudate die swell B is substantially reduced by the presence of glass fibers. Consequently, these rheological properties except extrudate die swell are caused by the large Weissenberg effect induced by glass fibers.