Influence of binder on the porosity of carbon materials

Resumo

The formation of porosity in carbon materials is considered. In hot-pressed materials with medium-sized grains, porosity is formed by the destruction of binder when blanks are fired to 600°C. In cold-pressed small-grain materials, shrinkage and binder destruction are responsible for the porosity. Up to 600°C, the yield of volatiles and shrinkage compensate the development of porosity, which mainly appears above 600°C. Using various binders, we may obtain carbon materials with small or large porosity. In addition, the binder affects the pore size and distribution. Methods of producing carbon materials with elevated porosity are considered, including the use of filler from a single size fraction and the use of pore-forming agents, Highly porous carbon materials are also produced from binder, with no filler. The raw materials employed are synthetic tars or mesophase pitch. The properties of carbon materials with different pore content are compared.