Polyacrylonitrile (PAN) fibers were pre-oxidized in a temperature range of 180-275℃. The effects of positive and negative stretching on the structure and morphology of PAN fiber in the pre-oxidation process were studied by FTIR spectroscopy, XRD, and SEM. Mechanical property changes were also investigated. No changes in the movement and intensity of functional groups of PAN fibers were caused by positive stretching of up to 10% and negative stretching down to -8%. The crystal structure can be affected by the positive stretching and negative stretching. The maximum strength is 479.81 MPa when the stretching is positive, and the maximum strength is 420.55 MPa when the stretching is negative.

• Liang Wang(State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology)
• Wei Lu(State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology)
• Li Zhang(State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology)
• Liwei Xue(State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology)
• Seung-Kon Ryu(Department of Chemical Engineering, Chungnam National University)
• Ri-guang Jin(State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology) Corresponding Author