Understanding the behaviour of synthetic polymer fibres during spinning

DEVAUX,Ecole Nationale Superieure des Arts et Industries Textiles (ENSAIT), and Centre Europeen des Textiles Innovants (CETI), France 

Most thermoplastic polymers have a strong tendency to crystallize during cooling. This phenomenon generally results in an isotropic arrangement of the macromolecules and must be controlled to ensure orientation in the fibre direction. The relaxation of the macromolecular chains at the exit of the dies causes a die swell phenomenon, which must also be treated to optimize the final properties of the yarns. 

Key words thermoplastic polymer rheology, crystallization, macromolecular superstructures, extrusion, die swell, drawing. 

Since the discovery of the qualities of natural silk around 3000 BC, mankind has tried to imitate nature by producing synthetic materials with similar properties to this material. The exceptional mechanical and handling properties of natural silk were and remain an absolute reference in the field of fibres. The artificial silk patented in 1884 by French Bernigaudde Chardonnet is often seen as the first significant development in man-made fibres. With the appearance of plastics at the beginning of the twentieth century, and the studies undertaken on the macromolecular structure of polymers by 

Hermann Staudinger, there has been an increasing development of these materials for numerous apphcations, including textiles. Polyamide 6.6 fibre (nylon), developed by Du Pont de Nemours in 1938, was a revolution in clothing and mihtary uses. This fibre, the functional characteristics of which are rather close to silk, has exceptional tenacity, flexibihty and lightness. With the progress of macromolecular chemistry at that time, it was the first of a long series of diverse synthetic fibres. 

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Understanding the behaviour of synthetic polymer fibres during spinning... 

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