首页 | 本学科首页   官方微博 | 高级检索  
     检索      


Stabilization of emulsions by heterocoagulation of clay minerals and layered double hydroxides
Authors:S Abend  N Bonnke  U Gutschner  G Lagaly
Institution:Christian-Albrechts-Universit?t Institut für Anorganische Chemie D-24098 Kiel Germany E-mail: h.mittag@email.uni-kiel.de, DE
Abstract: Paraffin/water emulsions were stabilized by colloidal particles without surface active agents. Mixtures of two types of particles with opposite signs of charge were used: a layered double hydroxide (the hydroxide layers carry positive charges) and the clay mineral montmorillonite (the silicate layers carry negative charges). The emulsions were very stable and did not separate a coherent oil phase. The stability of the emulsion (no oil coalescence after centrifugation) was independent of the mixing ratio of both the compounds when the total solid content was >0.5%. Solid contents up to 2.0% were optimal. In contrast to stability, flow behavior of the emulsion was dependent on the mass fraction χ of the hydroxide. The maxima of viscosity and yield value were observed at χ≈0.2–0.3; the emulsion showed pronounced antithixotropic behavior. Weak thixotropic properties, smaller viscosities and yield values were observed at χ≤0.2 and ≥0.5. In the absence of the clay mineral, the double hydroxide particles stabilize by forming envelopes around the oil droplets. Addition of bentonites creates a three-dimensional network of particles with high elasticity which impedes coalescence of the oil droplets. Received: 9 March 1998 Accepted: 6 April 1998
Keywords:  Aluminum magnesium hydroxide  antithixotropy  bentonite  emulsions  montmorillonite  Pickering emulsions  layered double hydroxide  solid stabilized emulsions
本文献已被 SpringerLink 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号