Preparation of Mesophase Pitch and High Performance Carbon Fiber from Decant Oil

The most efficient process conditions for the preparation of mesophase pitch and carbon fiber from decant oil were studied. Mesophase pitch was very low when prepared directly by one step. A preparation method combining heat-treatment under pressure and heating under nitrogen flow improved the mesophase pitch yield to 19%. The optimum raw material was aromatic rich decant oil with a density of 1.05 g/cc or more. Solubility changes of pitch fiber during stabilization were presented, e.g., benzene soluble, benzene insoluble-quinoline soluble, and quinoline insoluble. The pressurizing heat treatment of the first step was optimum at about 400°C based on reaction time and solid carbonaceous formation. Carbon fiber thinner than 10 μm could be spun from mesophase pitch with lower content of quinoline insoluble material. Carbon fiber spun from mesophase pitch with higher quinoline-insoluble content displayed higher Young's modulus and tensile strength. Stabilization in air with 2% NO₂ improved the tensile strength.