Stabilization kinetics of gel spun polyacrylonitrile/lignin blend fiber

Composite fibers from polyacrylonitrile (PAN) and softwood lignin (SWL) were successfully fabricated to investigate the effects of lignin on fiber properties and thermal stabilization reaction kinetics. PAN/SWL composite precursor fiber exhibits comparable tensile properties to PAN fiber. This is attributed to the antiplasticization effect of lignin on PAN. Thermal stabilization reactions (e.g. oxidation, cyclization, and crosslinking) for both PAN and PAN/SWL fibers were individually studied by different scanning calorimetry. The addition of SWL was shown to reduce the activation energies and increase reaction rates of cyclization, oxidation and crosslinking. Thermo-mechanical analysis (TMA) was employed to monitor the effect of applied tensions on PAN cyclization kinetics under non-isothermal heating process. Cyclization activation energies of PAN/SWL fiber are shown to be consistently lower than those of PAN fiber under all applied tensions. Calculations of cyclization reaction kinetics constants from TMA indicate that SWL can promote PAN cyclization and crosslinking. (C) 2016 Elsevier Ltd. All rights reserved.