Polyacrylonitrile/boron nitride nanotubes composite precursor and carbon fibers

Polyacrylonitrile (PAN)/boron nitride nanotubes (BNNTs) composite fibers were spun using gel spinning method and the resulting carbon fibers were processed after the fibers were stabilized in air and subsequently carbonized in nitrogen. PAN fibers containing 1 wt% BNNTs show comparable drawability to the control PAN fiber while the drawability of composite fibers significantly decreases as BNNT concentration increases from 1 to 5 wt%. Differential scanning calorimetry suggests that the presence of BNNTs reduces the activation energy of oxidation and crosslinking reactions but has little effect on the activation energy of cyclization reaction during stabilization. In the PAN/BNNTs based carbon fibers, the graphitic carbon structure that formed in the vicinity of BNNT was directly observed by transmission electron microscopy. (C) 2019 Elsevier Ltd. All rights reserved.