Modification of fiber-forming polymers by additives

Abstract

This review article deals with the modification of synthetic fibers by polymeric additives. It gives an account of the development of the modification of synthetic fibers by polymeric additives, starting from the industrially interesting project concerned with the development of polyamide/polyethylene terephthalate blend fibers and aimed at the improvement of elastic and recovery properties of polyamide fibers. It became apparent that chemical and physical interactions at the interface are very important in the structure of the fiber-forming blend formation and has influence on their processability and properties of fibers. For this reason, the review also deals with the basic methods for evaluation of the interactions of polymer components in the blend. The significant influence of the blend structure on the processability during spinning and drawing of fibers and also on the properties of blend fibers has become a background for the elaboration and application of rheological relations being valid for the polymer dispersion as a whole (macrorheology) and for the behavior of the dispersion phase in the mixing and deformation process (microrheology) in shear and elongation conditions. The next part of the contribution is devoted to some types of blend fibers based on commercial polymers which have the greatest possibilities of exploitation. The color concentrates for dyeing, mainly synthetic fibers prepared by spinning from the melt are produced in large volumes, especially for polypropylene and, to a lesser extent, for polyester and polyamide fibers. With regard to their significance, they are an object for the further part of the contribution submitted. Here, attention is paid to the influence of pigment properties, polymer carrier and dispersant on the processability of pigment in the preparation of concentrates and on the miscibility of concentrates with a colored polymer. The article also deals with the modification influence on the supermolecular and morphological structure of fibers with respect to all types of modification. In evaluating the processability of pigments and concentrates, several non-traditional methods have been developed, particularly from the viewpoint of rheology and the filterability of dispersion. The review is not aimed at the overall quantification of the periodical literature and patents considerably exceeding the present range of this contribution. The article includes some works of less-known journals in the world, which are dealing with the development of modified synthetic fibers by polymeric additives as well as with the development of color concentrates for polypropylene and polyester fibers.