Carbon whiskers reinforced porous glassy carbon composites by synchronous growth

A crystalline and non-crystalline composite of pure carbon was proposed, which is a carbon whiskers reinforced porous glassy carbon composite, where crystalline carbon whiskers support the microscopic pores of noncrystalline glassy carbon matrix. Two allotropes of carbon were produced simultaneously and compounded together in a single high temperature treatment of thermosetting phenolic resin, with aluminum oxide (Al2O3) as a catalyst. A synchronous growth theory was proposed to explain the growth mechanism. In the pyrolysis process of phenolic resin to generate porous glassy carbon, hydrocarbon gas was produced and trapped in the generated pores. By the same time, the hydrocarbon gas in pores was decomposed and grew carbon whiskers by catalysis of Al2O3. With linear thermal expansion coefficient from 2.0 center dot 10- 6 to 3.8 center dot 10- 6 K- 1, thermal conductivity from 1.763 to 2.518 W center dot m- 1 K- 1, specific heat capacity from 0.396 to 0.752 J center dot g- 1 K- 1, thermal diffusivity from 6.115 to 4.598 mm2 s- 1, between room temperature (RT) and 500 degrees C, the Vickers hardness is at 65 MPa, and the fracture toughness is at 0.329 Mpa center dot m1/2 in RT. The carbon whiskers reinforced porous glassy carbon composite keeps a balance between thermophysical and mechanical properties, showing its application value in thermal insulation materials and high temperature structure materials.