摘要:

Contact angles of various mineral oils and water on relatively polar and non-polar calcium stearate surfaces prepared by special means were measured. Pre-moistening of the soap surface with small quantities of water decreased the subsequent contact angle against oil. The effect of the polarity of the oil was determined, and the action of water in the system is discussed.The sedimentation volume of calcium stearate in mineral oil, with and without various added materials, was measured. Water, glycerol, and alcohol effected an agglomeration of the suspended soap, and less polar liquids had no effect. Fatty acid in small quantities brought about a swelling of the soap at room temperature. The relation between wetting power and sedimentation volume is discussed.

ISSN:1923-4287    

DOI:10.1139/cjr44b-019

出版商:NRC Research Press    

年代:1944

数据来源: NRC

摘要:

Calcium stearate undergoes a partial melting to a mesomorphic state at about 100 °C, as shown by discontinuities in the density–temperature relation and in differential cooling measurements, and by the onset of plasticity. No surface activity is exhibited by the soap in mineral oil, even in the mesomorphic state. Calcium stearate dispersions in a non-polar mineral oil are essentially lyophobic up to 180 °C, whereas the soap is dispersed to a sol in more polar oils at a temperature slightly above the partial melting point.The viscosity of these dispersions, measured over a range of temperatures in a variable-pressure efflux viscosimeter shows unusual characteristics. A maximum viscosity at intermediate temperatures was found, accompanied by a high degree of dilatancy. The presence of water is shown to lower the viscosity and destroy dilatancy by agglomeration of the dispersed soap.

ISSN:1923-4287    

DOI:10.1139/cjr44b-020

出版商:NRC Research Press    

年代:1944

数据来源: NRC

摘要:

The effect of various factors on the stability and physical properties of suspensions of recrystallized calcium stearate is shown. Non-polar oils form lyophobic systems that are unstable. Polar oils yield suspensions that are stable and lyophilic in character with little or no rigidity.The effect of small quantities of water is very marked. As a result of agglomeration, a structure is developed, and the system shows a strong stream double refraction. Lower alcohols have a similar effect. Fatty acid brings about agglomeration also but increasing quantities produce a solvent effect.Calcium oleate behaves similarly to calcium stearate, but the linoleate shows less stability.

ISSN:1923-4287    

DOI:10.1139/cjr44b-021

出版商:NRC Research Press    

年代:1944

数据来源: NRC