Accession Number : AD0454821


Title :   MANIFESTATIONS OF CHANGES WITH AGE IN SILICA HYDROGELS,


Corporate Author : NATIONAL RESEARCH COUNCIL OF CANADA OTTAWA (ONTARIO) DIV OF APPLIED CHEMISTRY


Personal Author(s) : Sirianni,A F ; Meadus,F W ; Puddington,I E


Report Date : 10 Jul 1964


Pagination or Media Count : 14


Abstract : Hydrocarbon oil dispersions of finely divided silica that has been prepared from aqueous solutions of sodium silicate by electrodialysis exhibit well-defined maximum yield values and sedimentation rates when the aquagels from which the silica was separated were prepared at about pH 5.5. A minimal electrophoretic mobility of the silica dispersed in oil and a pronounced minimum in the gelation time of the aquasols are also observed here. These maximal and minimal effects are presumably associated with the isoelectric point of the silica which is observed to be in the vicinity of pH 5. It was found by Plank and Drake that the surface area of silica gels increased as the aquagels from which they were prepared were aged in a closed system. It was therefore of interest to look for changes in other properties of silica that might depend on the age of their aquagels. In particular, properties that depend on interaction between suspended silica particles have been examined. (Author)


Descriptors :   *GELS , *SILICON COMPOUNDS , AGING(MATERIALS) , DIOXIDES , CANADA , COLLOIDS , OILS , PARTICLES , HYDROCARBONS


Distribution Statement : APPROVED FOR PUBLIC RELEASE