Improvement in the pore structure of polybenzoxazine-based carbon xerogels through a silica templating method

Abstract

Polybenzoxazine (PBZ) is synthesized by a facile quasi-solventless method within 1 h of synthesis time and less than 24 h of gelation time without any need of heating, and used as a carbon xerogel precursor. The pore structure of PBZ-based carbon xerogel is improved by using silica nanoparticles as hard templates. A mesoporous carbon xerogel with uniform pore is successfully synthesized. TGA, energy dispersive X-ray analysis, and field emission scanning electron microscope are used to confirm the successful incorporation of silica template into the microstructure of PBZ xerogel. Depending on the amount of silica template loading (10–50 % w/w), the specific surface area of carbon xerogel is improved to 518–899 m2/g, comparing to that of reference carbon xerogel of 362 m2/g. The standard adsorption isotherm of carbon xerogel is changed from type I to type IV after silica templating method is used. Extremely large amounts of meso- and total pore volume of 1.04–4.26 and 1.34–6.05 cm3/g, respectively, are obtained for carbon xerogel by the current method. In addition, the amount of micropore volume in carbon xerogel is not affected by silica template.