Abstract
The aim of this study is the development of polymeric and hybrid organic-inorganic nanoparticles with applications in the fields of nanotechnology. More specifically, nanotechnology is applied (i) in the field of material science for the production of hybrid organic-inorganic composite nanoparticles, which will be used as coating materials in order to enhance the properties of electrogalvanized steel (i.e., abrasion resistance, anti-corrosion) and (ii) in pharmaceutics and biomedicine for the development of biocompatible and biodegradable nanoparticles, which will be used as drug delivery systems. The first part of this study deals with the synthesis of hybrid organic-inorganic composite particles by different polymerization techniques (e.g., precipitation polymerization, emulsifier-free emulsion polymerization). Depending on the polymerization technique, polystyrene-silica composite particles, with different sizes were produced. Precipitation polymerization led initially to the synthe ...
The aim of this study is the development of polymeric and hybrid organic-inorganic nanoparticles with applications in the fields of nanotechnology. More specifically, nanotechnology is applied (i) in the field of material science for the production of hybrid organic-inorganic composite nanoparticles, which will be used as coating materials in order to enhance the properties of electrogalvanized steel (i.e., abrasion resistance, anti-corrosion) and (ii) in pharmaceutics and biomedicine for the development of biocompatible and biodegradable nanoparticles, which will be used as drug delivery systems. The first part of this study deals with the synthesis of hybrid organic-inorganic composite particles by different polymerization techniques (e.g., precipitation polymerization, emulsifier-free emulsion polymerization). Depending on the polymerization technique, polystyrene-silica composite particles, with different sizes were produced. Precipitation polymerization led initially to the synthesis of micro-particles (~3μm) with low silica content (<1%wt). In the present study, the process parameters affecting the particle size and the silica content were examined and a decrease in mean diameter of the produced particles (400- 850nm) as well as an increase in the silica content (15%wt) was achieved. The innovation in this work is based on the use of the auxiliary monomer 4-vinylpyridine, which can increase the acid-base interaction with the inorganic silica nanoparticles. More specifically, by applying precipitation polymerization, perfectly spherical, uniform in size, with the inorganic silica nanoparticles arranged in the surface of the synthesized composite nanoparticles were produced, which were successfully codeposited from an acid zinc plating bath resulting in the production of rather uniform composite zinc coatings. Polystyrene/silica composite nanoparticles were also synthesized by emulsifier-free emulsion polymerization. More specifically, composite nanoparticles with average mean diameter of 110nm and a silica content of approximately ¬38%wt were synthesized using a Styrene:1-vinylimidazole monomer system at various molar ratios. The auxiliary monomer 1- vinylimidazole acts in the same way as 4-vinylpyridine in precipitation polymerization, i.e., increases the acid-base interaction between the inorganic and organic phase. Perfectly spherical, uniform in size, raspberry-like composite nanoparticles were thus produced by emulsifier-free emulsion polymerization. The most optimized recipe was successfully upscaled and a study was performed to confirm the formation of a silica monolayer on the surface of the polystyrene particles. The produced composite nanoparticles were used for the production of composite zinc coatings on steel. In the second part of the present study, the production of biocompatible and biodegradable polymeric nanoparticles for drug encapsulation is evaluated. Various techniques were employed for the production of the carriers depending on the materials used. More specifically, a modified spontaneous emulsification solvent diffusion method was used for the synthesis of PLGA nanoparticles. The aim was to satisfy pharmaceutically acceptable criteria by using non toxic solvents, mild reaction conditions and to decrease the reaction time. PLGA nanoparticles having an average diameter of 210-350nm were synthesized and an effort was placed to encapsulate the anti-proliferating agent Rapamycin. The produced nanoparticles were finally lyophilized in order to receive them in a solid state. Finally, effort was placed for the production of PACA nanocapsules by an anionic interfacial polymerization technique and the effect of various parameters on the formation of the emulsion was investigated. PMCA particles were also synthesized by using an inhibitor in the organic phase and PVA. It was shown that when chitosan was used for the initiation of the polymerization, the nanoparticles could be received in a solid state after lyophilization.
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