A gel-fiber structure with low orientation should be expected since molecular relaxation occurs rapidly at the extrusion temperature (well above the PEO melting temperature) and the extrusion speed was relatively low; therefore, shear induced orientation
through the die orifice would be less likely retained in the quenched gel-fiber.
However, the flow induced orientation
is expected to be a significant concern in design, especially of parts having long flow lengths and thinner walls.
It can be observed that the induced orientation
for uniaxial tension tests is typically higher than for plane strain tests.
The increase in strength among the vibrational molded parts can be attributed to the flow induced orientation
and alignment of polymer molecules.
130] do not represent the true orientation function for the crystalline structure, they can be used to compare the induced orientation on different systems.
It can be remarked that the fracture parameters obtained by EWF are more sensitive to the induced orientation than the ones obtained by the mechanical tensile tests performed at the same testing rate.
In other words, we want to make some limiting assumptions, whereby we can derive an approximate version of the Mooney equation to judge if the SHCD does really indicate a direct relationship between degree of induced orientation
and slip at the die wall.
Forcing the cooler, more viscous melt into the mold produces higher levels of orientation than seen during conventional fill and packing in which any flow induced orientation
dissipates almost immediately.
The birefringence from cooling induced orientation
is comparable in magnitude to that from flow induced orientation
These steps induced orientation
only of a certain fragment of dipole, and the sample was then quenched to 0[degrees]C to freeze-in that orientation.
To counter-act this longitudinal flow induced orientation
, one or both surfaces of the die are moved transversely with respect to one another.
This allows the shear strain induced orientation
to be easily characterized by the extinction angle through a polariscope setup.