Abstract
Poly (ethylene terephthalate) (PET) was mixed with a block copoly(ester-ether) (PEE) and spun into fine fibers by a melt process. The blend fibers were drawn in water at 92°C and annealed at 200°C in silicone. The microstructure of the blend fibers was investigated by means of WAXS, DTA, microscopy, density measurement, and tensile experiments. In all fibers, PET was distributed as continuous fine fibrils in the matrix of PEE. The diameter of a PET fibril was almost in proportion to the PET content and of the order of 0.1 micron. The matrix PEE was in unoriented state due to the annealing above its Tm. Tensile properties of the blend fibers were rather tough and elastic because of the cooperation of the elastmeric PEE with highly oriented and crystallized PET. These structure and tensile properties were compared with those of natural wool. The formation of copolyester due to an interesterification between PET and PEE was disclaimed by means of WAXS and DTA experiments: The reflections of both components were clearly distinguished in their x-ray scattering diagrams and the melting peaks of PET and PEE were separately observed in their DTA traces.
