Amount Of Silanol Groups Research Articles

A study on the components of surface free energy of quartz from contact angle measurements

Measurements of the contact angle for water, glycerol, formamide, diiodomethane and 1,1,2,2-tetrabromoethane on a quartz surface were made. Using the results obtained, the “geometric mean” approach and long-range and acid-base interaction approach, the dispersion, non-dispersion, Lifshitz-van der Waals and acid-base components of the surface free energy of quartz were determined and compared with those determined in different ways. On the basis of the measurements and calculations it was found that the surface free energy of quartz depends largely on the amounts of silanol groups and physically adsorbed water molecules on its surface. It was also found that the two tested approaches to surface free energy of solids and liquids gave similar results, and it is suggested that the surface free energy of quartz results mainly from dispersion and hydrogen-bond intermolecular interactions.

シラノール基を側鎖に有するポリビニルアルコールとコロイド状シリカからなる複合材について

シラノール基を側鎖に有するポリビニルアルコールとコロイド状シリカからなる複合材について

Effect of surface treatment of particles on the rheological properties of suspensions

The amount of silanol groups on the surface of silica particles varies due to a condensation reaction caused by heat treatment. This variation is measured by infrared spectroscopy. The variation affects the rheological properties of suspensions of these particles in polymer solutions. This effect is studied using a coaxial cylinder rheometer. The flow curves and dynamic viscoelastic function of suspensions show a pseudoplastic plateau in the flow region of polymer solutions. There is a close correlation between the height of the plateau and the absorbance of the 3450-cm −1 band characteristic of surface silanol groups. It is concluded that the surface silanol groups are primarily responsible for the flocculation of particles in suspensions.