Fibers high stress spinning

High stress spinning of the fibers Optimization of the cord construction variables... 

Another feature of high-speed spinning is that the fiber macro structure becomes non-uniform, with more orientation and crystallinity near the fiber surface than in the interior. This is a result of non-uniform solidification, where rapid cooling generates a lower temperature and higher viscosity at the surface. This leads to an oriented surface skin which supports the spinning stress, while higher temperatures within the interior allow more relaxation and disorientation. 

The melt-spinning process used to convert mesophase pitch into fiber form is similar to that employed for many thermoplastic polymers. Normally, an extruder melts the pitch and pumps it into the spin pack. Typically, the molten pitch is filtered before being extruded through a multi-holed spinnerette. The pitch is subjected to high extensional and shear stresses as it approaches and flows through the spinnerette capillaries. The associated torques tend to orient the liquid crystalline pitch in a regular transverse pattern. Upon emerging from the... 

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