Effects of Fiber Spinning on the Morphology, Rheology, Thermal, and Mechanical Properties of Poly(trimethylene terephthalate)/Poly(ethylene terephthalate) Blends

ABSTRACT The morphology, thermal behavior, rheological, and mechanical properties of poly(trimethylene terephthalate) (PTT)/poly(ethylene terephthalate) (PET) blend fibers were investigated. The scanning electron microscopy studies revealed the formation of a microfibrillar network of the PET within the PTT matrix after the fiber‐spinning process. Differential scanning calorimetry results demonstrated that although the thermal characteristics of the amorphous phase were unaffected by the fiber‐spinning process, the melting and crystallization behavior of the blends was altered by the elongation flow imposed during the melt spinning. The viscoelastic behavior of the PTT/PET blends was also studied by a steady shear rate and dynamic sweep rheological experiments before and after the spinning process. The induced morphology and crystallization reordering resulting from the fibrillation process are shown to have a remarkable effect on the complex viscosity profile of the PTT/PET fibers, particularly in the blend containing 30 wt% PET. The mechanical testing showed that tenacity and Young's modulus of the PTT fibers increased with the addition of PET up to 30 wt%.