Melt spinning property development

Mechanical Properties. Polyester fibers are formed by melt spinning generally followed by hot drawing and heat setting to the final fiber form. The molecular orientation and crystalline fine stmcture developed depend on key process parameters in all fiber formation steps and are critical to the end use appHcation of the fibers. 

Ternary blends from a thermotropic liquid crystalline polymer, PEN, and PET were prepared by melt blending and melt spinning to fibers. The mechanical properties of ternary blend fibers could be significantly improved by annealing at 180°C for 2 h. This is attributed to the development of more ordered crystallites and to the formation of more perfect crystalline structures. The interfacial adhesion between PEN and liquid crystalline polymer phases is enhanced when the blends are processed with dibutyl-tindilaurate as a reactive catalyst to promote transesterification. 

Gulgunje P, Bhat G, Spruiell J. Structure and properties development in poly(phenylene sulfide) fibers, Part I effect of material and melt spinning process variables. J Appl Polym Sci 2011 122(5) 3110-21. 

Melt spun fibers are subjected to a hot drawing process to encourage polymer chain orientation and the development of crystallinity witl the fibers. Electrospun polyester has been produced via melt spinning , but in order to render fimctionality to the resulting material, gelatin was incorporated by subsequent surface modification involving formaldehyde. This in turn improves physical fiber properties, but slows the diffusion of small molecular species within the fiber (thus, for exanqile, imdrawn polyester dyes more readily than drawn material). The shorter diffusion path out of fine fib is responsible for lower color fastness of febrics derived ifom them. 

Nadella, H., Henson, H.M., Spruiell, J.E. and White, J.L. (1977) Melt spinning of isotactic polypropylene structure development and relationship to mechanical properties.. Appl. Polymer Sci., 21, 3003-22. 

Furthermore, the relatively uncomplicated situation in the melt>spinning process when the fiber has solidified actually permits meaningful analysis of the development of fiber properties for this region. 

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