Spinning of lyotropic solutions

Conio et al. studied the fiber formation of PpBA from an organic solvent, A, A -dimethylacetamide containing 3% LiCl, but in these experiments an air gap was hardly used. This may be the reason why they arrived at somewhat different conclusions concerning the spinning of para-aromatic polyamide solutions. 

This figure demonstrates the importance of the spin-stretch stage in the spinning process. It will be shown here that these results are in agreement with the affine deformation model.  

For the affine deformation, which describes the orientation of a rod-like particle embedded in an elastic matrix, the parameter p in eqn (6.10) equals 3/2. Kuhn and Griin, as well as Ward, derived a relation between the birefringence and the draw ratio which, in fact, is the relation between the order parameter 2 the draw ratio  

The overall order parameter, 2 for an oriented nematic solution may be expressed in terms of the order parameter of the director field of the domains, and of the molecular order parameter, P2 ) characterizing the degree of order inside the domains, according to 

Before entering the air gap the spinning solution is subjected to a so-called pre-draw, Xq, due to the spinneret. Hence, the effective draw ratio pertaining to the affine model, A, is given by 

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