Characteristics of PET in ScCO2 foam spinning process

In recent years, supercritical CO₂ (scCO₂) foaming fibers have attracted considerable attention. However, the preparation of microporous structured foamed fibers is immature. Currently, the combination of foaming and spinning is an emerging topic, full of challenges. During the processing, the preparation of microcellular foamed fibers necessitates a thorough understanding of the foamability, thermal properties and rheological properties of the material. These properties significantly influence the performance of nucleation, and the distribution of cells. In this work, comprehensive analysis of PET foamability, thermal properties and melt rheology was conducted, rheology encompassing all critical processing stages, including melting in the twin-screw section, homogenization in the single-screw section, extrusion through the spinneret, and subsequent stretching after extrusion. The rheology of the entire process is of paramount importance, as this work aims to contribute to the research on the preparation of spinning microporous ultrafine foamed fibers.