Influence of polymer characteristics and melt‐spinning conditions on the production of fine denier poly(ethylene terephtalate) fibers. Part III. Structure and properties of fine denier as‐spun PET fibers

Abstract

AbstractThe effect of decreasing take‐up denier on the structure and mechanical properties of asspun poly(ethylene terephtalate) (PET) fibers is shown to be, in general, similar to an increase of take‐up velocity. Both can be related to increased threadline cooling rate and increased spinline stress that control the structure development in the threadline. However, important distinctions were observed in the orientation and crystallization effects due to decrease of take‐up denier or increase of take‐up velocity. These distinctions were explained on the basis of the threadline dynamics study of the fine denier PET fiber in the high‐speed spinning process, discussed in Part II of this study. Other properties, such as the dynamic mechanical properties and dye uptake, are not related to individual structure parameters, depending on the overall changes in structure, e.g., as given by the free volume.