الفهرس 
Chapter 1 :IntroductionOnly 14 pages are availabe for public view
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Abstract
We have prepared and characterized different stable simple (o1/o2) and double (o1/o2/o1) non-aqueous emulsions by using silica nanoparticles as a sole stabilizer and explored the feasibility of using these non-aqueous systems in some applications. The following main conclusions can be drawn concerning the results obtained in this thesis:
1. Four types of simple Pickering non-aqueous emulsions namely olive/gly, gly/olive, castor/gly and gly/castor were successfully prepared in recognition of the essential desirability of gaining information on the technology of these promising systems. These emulsions were prepared by using different concentrations of 50% SiOH silica nanoparticles. The influence of particle concentration and droplets volume fraction on the kinetic stability of the resulted emulsions was studied and can be summarized as the following:
• The emulsions were completely stable to coalescence for more than two months but susceptible to gravity induced separation (creaming or sedimentation) at relatively low concentrations of silica nanoparticles.
• As the concentration of silica nanoparticles increased, the creaming index and viscosity values increased but the average droplet diameter decreased.
• The viscosity and flow behavior for simple non-aqueous Pickering emulsions were studied for the first time.
• Upon varying the volume fraction of the dispersed phase, CPI was obtained in the four types of emulsions. This was confirmed by the optical microscope images and DROP test.
• High internal phase emulsions (HIPEs) of glycerin-in-olive oil were successfully prepared using 50% SiOH silica nanoparticles as a stabilizer and a low energy emulsification method.
• Olive oil-in-glycerin emulsion was successfully used to limit the in vitro release of aspirin and the release data was best fitted with the Higuchi rate equation indicating that the release follows a square root of time relationship.
2. Two types of double Pickering non-aqueous emulsions namely castor/gly/castor and gly/castor/gly were successfully prepared by using only one type of silica nanoparticles, possessing 50% SiOH, for the first time. The influence of particle concentration and globule volume fraction on the kinetic stability of the resulted emulsions was investigated and can be summarized as the following:
• The emulsions were completely stable to coalescence for over a month but susceptible to creaming or sedimentation at relatively low concentrations of silica nanoparticles.
• As the concentration of silica nanoparticles increased, the creaming index and viscosity values increased.
• Upon varying the volume fraction of glycerin globule (c/g), in castor/gly/castor double emulsion, the CPI was obtained at c/g > 0.6 after which the double emulsions were inverted to the other type (gly/castor/gly). This was confirmed by the optical microscope images and DROP test.
• In case of gly/castor/gly double emulsion, upon varying castor oil globule volume fraction (g/c), CPI occurred at g/c > 0.5 after which the double emulsion was inverted to simple castor/gly emulsions.
• The viscosity and flow behavior for these non-aqueous double Pickering emulsions were studied for the first time. Variation of the two double emulsions viscosities against the shear rate revealed the non-Newtonian shear thinning behavior.
• Gly/castor simple emulsion and castor/gly/castor double emulsion were successfully used to control the in vitro release of aspirin. The release data of simple and double emulsions were best fitted with zero-order rate equation for prolonged release.
3. Different functionalized polymeric materials were successfully prepared from the polymerization of simple non-aqueous Pickering emulsions, and some conclusions can be summarized as the following:
• In simple non-aqueous Pickering emulsions in which the continuous phase was a monomer oil during varying the volume fraction of the dispersed phase, the CPI occurred and the monomer oil became the dispersed phase. After polymerizing these series of emulsions, we obtained porous polymer and polymeric microparticles from the emulsions before and after the CPI, respectively. The porous polymer and microparticles structure were illustrated by SEM images.
• Porous polyMIPEs were obtained from the polymerization of medium internal phase emulsion, = 0.5, of gly/styrene and formamide/styrene Pickering emulsions. The porous structure of the formed monoliths were illustrated by SEM images.
• Polymeric magnetic microparticles, which are considered a functional nanostructure with excellent potential for many applications, were obtained from polymerization of pre-made polymerisable styrene/gly and styrene/formamide emulsions. The structure of microparticles and the presence of magnetite in it was confirmed by SEM images and exposure to external magnetic field.
4. Different functionalized monoliths and microparticles were successfully prepared from the polymerization of double non-aqueous Pickering emulsions, and some conclusions can be summarized as the following:
• Polymeric microparticles obtained from the polymerization of formamide/styrene/formamide as the globules of styrene, which surrounded by silica nanoparticles, were polymerized.
• If the styrene existed in the internal and outer phase of emulsion like styrene/formamide/styrene double emulsion, we can polymerize the outer styrene phase or the outer and internal one to obtain two types of monoliths. In the second case we obtained monoliths with large pores which entrap a significant amount of polystyrene microparticles in clusters indicative of the successful polymerization of the internal styrene drops, these could not be seen in the first case. This was confirmed through SEM images.
5. Oil foams were successfully prepared by using non-aqueous liquids and 23% SiOH silica nanoparticles as a foaming agent.
6. A dry oil powder was obtained from phase inversion of oil foams at high particle: oil ratio. This inversion was confirmed by optical microscope images and DROP test.