Porous Melt Blown PBT Fibers with High Ductility and High Temperature Structure Stability*

Melt blowing is an efficient and highly scalable method of producing nonwoven microfibers commonly used in high performance filtration and coalescence media. Development of new melt blowing resins in the form of immiscible polymer blends can produce nonwoven mats with tailorable structures and diverse properties, enabling application to fields like water remediation and tissue scaffolding. Specifically, cocontinuous blends can contain a sacrificial phase which templates structure during melt blowing and can then be extracted to produce porous melt blown fibers. We applied this templating method to produce porous poly(butylene terephthalate) (PBT) fibers which display remarkable ductility and retain fine structural features at temperatures over 150 °C. Single fiber tensile testing, detailed electron microscopy, and microstructural characterization demonstrate the role of the characteristic rapid quenching and extension of the melt blowing process in defining fiber morphology and properties. The highly oriented pore structures and thermal stability are ideal for traditional melt blown fiber applications, while the decreasing radial pore size distribution and demonstrated utility of the ester functionalization suggest applicability in other high value applications.