Effects of carbonization conditions on properties of carbon fiber prepared from liquefied wood in phenol

The carbon fiber precursors were prepared from liquefied wood in phenol by adding hexamethylenetetramine and soaking in the solution containing hydrochloric acid and formaldehyde as the main components. The carbon fibers were obtained from the precursors by the direct carbonization. The influence of the carbonization condition on the mechanical properties and yield of the carbon fibers was investigated by the paper frame method. The results show that the mechanical properties of the carbon fibers increase obviously with increasing carbonization temperature and time，but decrease with increasing the heating rate.  It is also found that the higher the wood/phenol ratio，the higher the increasing amplitude of mechanical properties，and the smaller the dimension shrinkage. Carbon fibers from liquefied wood with tensile strength of 1.7 GPa，tensile modulus of 159 GPa and yield of 60% were reached under optimal carbonization conditions.