Study On The Preparation And Properties Of Mesophase Pitch-Based Carbon Material With High Thermal Conductivity

The rearch studied the spinning technology of the ribbon-shaped fibers.The cross section of the fibers was observed by Scanning Electron Microscopy(SEM).Carbon plate with high thermal conductivity was made through self-sintering.The effects of oxidizing temperature and the B, Ti, Ti-B graphititzation catalysts were investigated by Infrared Spectroscopy(IR), Scanning Electron Microscopy(SEM) and Energy Dispersive Spectrum(EDS). We studied influence of the arrange style of graphite fiber on thermal conductivity and mechanical properties of the graphite fiber/epoxy-resin composite.The experimental data show that the optimal technological congditions of the ribbon-shaped fibers are:constant temperature 330℃, the temperature of spinneret hole is 300℃-305℃, spinning pressure is 0.009-0.014Mpa, spinning speed is 600-800r/min. The aspect ratio of the ribbon-shaped fiber can be 1.56.The oxidizing temperature affect the thermal conductivity and the mechanical properties of the carbon plate heavily. Plate oxidized at 240℃has the highest bending strength (184.05Mpa, average bending strength is 168.66MPa), while the plate oxidized at 260℃has the highest conductivity(852.08 W·m-1·K-1).B,Ti,Ti-B catalysts an be modified on the surface of the carbon plate by a sol-gel synthesis method. Results shows that not the addition of the catalyst the better the graphitization. The carbon plate get the highest graphitization degree and conductivity (992.4W·m-1·K-1) when the mass fraction of B is 3%. Compared to single Ti catalysts, effect of graphitization is better when use single B catalysts. While the rearch showed that the carbon plate with the highest conductivity(996.45W·m-1·K-1) was achieved in treating the plate oxidized at 260℃using a Ti-B sol catalysts.The mechanical properties and thermal properties of mesophase pitch based raphite fiber/epoxy-resin composite material has been studied. Results shows that the composite with fiber parallel-arranged has better mechanical properties than the cross-arranged composite material (two-dimensional). The conductivity follow the fiber axis of the o parallel-arranged composite is 552.18w·m-1·K-1,47.24w·m-1·K-1 higher than the cross-arranged composite. Change the arrange style of graphite fiber can weaken the anisotropy of conductivity. The weaking extent depends on the arrange style of the fiber and the fiber content on the cross direction.