Effect of ultrasonic etching treatment on structure and properties of stabilized PAN fibers

PAN fibers were stabilized by gradient elevation of temperature, and the fibers stabilized at different temperatures were etched ultrasonically in 90% dimethyl sulfoxide aqueous solution. The effect of ultrasonic etching treatment on chemical constitution, fibrillar structure and properties of the fibers stabilized at different temperatures was studied by FTIR and SEM. The results show that ultrasonic etching treatment has no effect on the chemical constitution of the fibers stabilized at different temperatures. But after ultrasonic etching treatment, separated fibrils appear in the fibers stabilized at 195-245°C. Due to ultrasonic etching treatment, certain degree of increase occurres in the linear density of all fibers. And the linear density of the fibers stabilized at 255°C reaches the peak value with the highest increase. The tensile strength of the fibers stabilized at different temperatures all decreases, and the tensile strength of the fibers stabilized at 255°C drops to the minimum value.