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Figure 2. Stress-strain curves of pure PAN and PAN/Zr(OAc)₄ composite nanofiber membranes. (A) Untreated and (B) 260 °C heat-treatment; (C) Comparison of stress and strain for pure and composite films untreated and 260 °C heat-treatment; (D) TGA curves of untreated and different heat treatment temperatures PAN/Zr(OAc)₄ membranes from 50 to 800 °C at a heating rate of 10 °C/min under N₂; (E) Column comparison chat of carbon yield and onset temperature for different heat treatment temperature PAN/Zr(OAc)₄ nanofiber membrane; (F) DSC curves of pure PAN vs. PAN/Zr(OAc)₄ membranes from 50 to 350 °C under N₂ with different heat treatment temperatures; DSC curves of PAN/Zr(OAc)₄ membranes at different heating rates: (G) untreated; (H) 260 °C heat-treatment and (I) plot of ln(Φ/T²_m) vs. 1,000/T_m according to the Kissinger. PAN: Polyacrylonitrile; Zr(OAc)₄: zirconium acetate; TGA: thermogravimetric analysis; DSC: differential scanning calorimetry.