Effects of carbonization temperatures on microstructure of carbon fiber precursors prepared from liquefied wood

In order to enlarge the utilization field of wood and decrease the costs of carbon fibers, carbon fiber precursors from liquefied wood were prepared by soaking liquefied wood in a solution containing hydrochloric acid and formaldehyde, after melt-spinning by adding hexamethylenetetramine. The microstructure evolution of the precursor during carbonization was studied by FTIR, X-ray analysis and Raman spectroscopy. The results show that precursors from liquefied wood above 400°C had diffraction peaks corresponding to the (100) crystal plane. When the carbonization temperature reached 500°C, Raman spectroscopy showed the D peak at wave number of 1360 cm⁻¹ and the G peak at 1595 cm⁻¹. By increasing the carbonization temperature, the microstructure of the precursors became more ordered. Although the structure of the precursor changed at 500 and 800°C, the peaks at 1632 and 1454 cm⁻¹ corresponding to the characteristic vibrations of aromatic rings, remained during carbonization. This implies that the precursor from liquefied wood cannot be easily formed into graphite.