Strong electrospun nanometer-diameter polyacrylonitrile carbon fiber yarns

Nanometer-diameter electrospun PAN yarns with different degrees of alignment were stabilized and carbonized and their properties evaluated. The parameters varied during production included draw ratio, temperature, heating rate and time in order to determine the ideal oxidation and carbonization conditions. The 10% PAN carbon yarn made at 16 kV and 9.8 m s−1 take-up velocity had the highest ultimate strength of approximately 1 GPa while maintaining constant length conditions during the process. The ultimate strength increased to approximately 1.7 GPa after the yarns were impregnated with an adhesive to make nano-sized unidirectional composite samples. The ultimate strength of PAN yarns generally increased with increasing take-up velocity because of the increase of molecular orientation.