Heat-resistant polybenzoxazole nanofibers made by electrospinning

•Heat-resistant electrospun PBO nanofibers were prepared from precursor OH-PAA.•The obtained PBO nanofibers are thermally stable up to 643 °C.•The obtained PBO nanofibers have excellent mechanical properties.•PBO nanofibers have retention of tensile strength and modulus over 80% at 350 °C.•Such heat-resistant PBO nanofibers could be used in high temperature fields.

Polybenzoxazole (PBO) electrospun nanofiber belts were successfully prepared in three steps, low-temperature polycondensation to synthesize precursor of PBO with 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 3,3′-dihydroxybenzidine (DHB), hydroxy-containing polyamic acid (OH-PAA), electrospinning OH-PAA solution to obtain nanofiber belts and thermal conversion to get PBO nanofiber belts. The structures of polymers were characterized by FT-IR and 1H NMR. The thermogravimetric analysis showed that 5% weight loss temperature was very high up to 643 °C in N2 atmosphere. CMT-8102 Electromechanical Universal Testing results indicated that PBO nanofiber belts possessed excellent mechanical properties with tensile strength of 525 MPa and Young’s modulus of 8.2 GPa. Further more, an excellent thermal mechanical properties tested by thermomechanical analysis (TMA) and dynamic mechanical analysis (DMA) showed that both the retention of tensile strength and storage modulus of PBO nanofiber belts were above 80% when the samples were heated at 350 °C in N2 atmosphere.

Graphical abstractThe prepared BPDA/DHB-based PBO nanofibers with diameter ranged from 100 to 350 nm perform excellent mechanical properties and thermal stability. The retentions of tensile strength and modulus at 350 °C are respectively above 90% and 80%.Figure optionsDownload full-size imageDownload as PowerPoint slide