Theory of crystallization in high‐speed spinning

Removal of the heat of fusion during steady‐state crystallization in a high‐speed spinline places restrictions on the morphology of the crystallites. An appropriate model is that of a thermal dendrite. It is shown that for this case there exists at each temperature along the threadline a limiting growth velocity, beyond which heat cannot be conducted away fast enough to permit growth. It is suggested that crystallization occurs when a fluid element reaches a temperature at which heat can just be conducted away rapidly enough. Comparison of dendrite theory predictions with experimental values of crystallite diameter and crystallization temperature shows satisfactory agreement. Poly(ethylene terephthalate) has been taken as the example.