Investigation of the Parameters of Adsorption of Ethylhydrosiloxane on the Surface of Tungsten Carbide

Abstract

The article deals with the modification of the surface of tungsten carbide powder with ethylhydrosiloxane. The morphology and granulometric composition of the original tungsten carbide have been studied. To modify the powder, the oligomer is preliminarily dissolved in n-hexane. It is found that the adsorption equilibrium is established in the first hour. Based on the data obtained, an adsorption isotherm of oligomeric ethylhydrosiloxane molecules on tungsten carbide particles is plotted as a function of the equilibrium concentration. It has been established that the adsorption isotherm of oligomeric ethylhydrosiloxane molecules on tungsten carbide particles has a typical character of monomolecular (monolayer) adsorption. At an equilibrium concentration of 0.12 mg/cm3, the adsorption isotherm curve reaches a plateau. Data on the determination of the parameters of adsorption of oligomeric molecules of ethylhydrosiloxane on the surface of tungsten carbide are presented: the landing area occupied by one oligomer molecule and the thickness of the adsorption layer of the oligomer. It is shown that modification with ethylhydrosiloxane leads to a transition from a hydrophilic to a hydrophobic surface. To establish the hydrophobization of the surface of tungsten carbide after modification with ethylhydrosiloxane, authors determine the contact angles of surface wetting before and after modification. At oligomer concentrations above 0.12 mg/cm3, the contact angle of wetting the surface of tungsten carbide with water has a maximum value of 96±2°.