Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
596000 | Colloids and Surfaces A: Physicochemical and Engineering Aspects | 2009 | 7 Pages |
Abstract
Carbonaceous materials with different hierarchical porous structures for electrorheological (ER) dispersed phase have been synthesized by carbonization of as-prepared starch/silica precurser at different temperatures. The N2 adsorption isotherms show that Cmeso-700 and Cmeso-500 particles have the BET surface areas of 1028 and 603Â m2Â gâ1, respectively. They both have the mesoporous pores with size of about 4.6Â nm and the microporous pores (1.1 and 1.5Â nm, respectively). The BET surface areas and C/O atomic ratio of porous carbon materials can be increased with the carbonization temperatures. The rheological measurements indicate that the Cmeso-700 and Cmeso-500 ERF have the better ER effect resulted from their hierarchical porous structures. The shear stress of Cmeso-700 ERF is 900Â Pa at 1000Â sâ1 under 3Â kVÂ mmâ1, which is almost 4.5 times larger than that of Cmicro-350 ERF. The mesoporous carbon ERFs also show the better sedimentation stability than microporous carbon ERFs. The different ER effect of carbonaceous particles may derive from their different dielectric polarization property induced by the hierarchical porous structures.
Keywords
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Colloid and Surface Chemistry
Authors
Yinpo Qiao, Xiaopeng Zhao,