Comparative properties of silicas

The physical properties of the different silicas, prepared by the above mentioned methods, are compared in table 1.2. 

Characteristics Pyrogenic silicas Silicas made by wet methods  

Mean pore diameter nm non porous till ca. 300 m2/g non porous 30 2 to 20 25 

Pore diameter distribution very broad narrow narrow 

Shape of interior surface Aggregation and 0 0 poor very much much 

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