Preparation and Properties of PBO Nanofiber Membranes via Electrospinning and Thermal Conversion

Abstract In this study, Polybenzoxazole (PBO) nanofiber membranes are prepared by applying a three-step process, including synthesis of the electrospinning precursor with ortho-hydroxyl, electrospinning, and thermal conversion. Electrospinning is conducted at 10 kV with a distance of 10 cm and the solution concentration is 17.8% (w/v). Different flow rates are adopted to prepare polymer nanofiber membranes and test their properties. At the rate of 0.5 μL/min and 1 μL/min, uniform and compact films with nanofibers are obtained. The high-temperature transition from the precursor to PBO is then investigated systematically. Thermal treatment at 420°C is needed for complete cyclodecarboxylation conversion from the precursor to PBO. Diameters of the fibers in the as-prepared PBO nanofiber membrane are within the range of 120-130 nm. The membrane shows high thermal stability with the decomposition temperature of 619.8°C in N 2 and 513.6°C in air respectively, presenting a promising application prospect in high-temperature areas.