Electrospinning of p -Aramid Fibers

Electrospun poly (p-phenylene terephthalamide) (PPTA) fibers with diameters between 275 nm and 15 µm were obtained from anisotropic solutions, albeit that the spinning process was difficult to control. Key solution parameters like conductivity, surface tension, and viscosity were used to compare the spinnability of these anisotropic solutions with common polymer solutions in order to better understand the challenges of spinning such solutions. Mechanical properties of the electrospun p-aramid single fibers were evaluated and it was found that Young's modulus and tensile strength increased dramatically with decreasing fiber diameter. A maximum Young's modulus and tensile strength of 59 and 1.1 GPa, respectively were found and a geometrical model for the size-dependent Young's modulus was developed to predict fiber properties based on rigid-rod chains down to the nanoscale.