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Study On Preparation And Properties Of Pure Acrylic Emulsion Modified By Inorganic Nanoparticles

Posted on:2012-02-27Degree:MasterType:Thesis
Country:ChinaCandidate:L ZhangFull Text:PDF
GTID:2131330338994783Subject:Applied Chemistry
Abstract/Summary:PDF Full Text Request
Pure acrylic emulsion modified by inorganic nanoparticles combines the properties of inorganic nanoparticles and organic polymer and it has improved water resistance, thermal stability and weather resistance of pure acrylic emulsion. Follow this line, systemic researches about pure acrylic emulsion modified by inorganic nanoparticles obtained by emulsion polymerization have been done, in order to obtain emulsion with outstanding properties. The main researches contact the modification of nanoparticles, synthesis techniques of pure acrylic emulsion modified by inorganic nanoparticles, characterization of emulsion properties and structure.A process for modification of nano-SiO2 and nano-TiO2 by KH570 and oleic acid respectively and the results of FT-IR and TG showed that surface modifiers had been grafted successfully on the surface of nanoparticles. The graft ratio of modified nano-SiO2 was 13.97% and the graft ratio of nano-TiO2 was 19.44%. The modified nanoparticles could be dispersed very well in organic medium and contact angle analyzer and dispersion stability test showed that the surface of nanoparticles after modification was hydrophobic. XRD showed that the surface modifiers had no effect on the crystalline type and structure of nanoparticles. And after modification, there are polymeric functional groups bonded on the surface of nanoparticles which provides conditions for emulsion polymerization of composites emulsion.The polymerization system and technique of pure acrylic emulsion modified by inorganic nanoparticles were studied. The effects of monomers, surfactants, amount of nanoparticles, initiator, and temperature et al. on the pure acrylic emulsion modified by inorganic nanoparticles were investigated, and the best formulation of pure acrylic emulsion modified by inorganic nanoparticles was determined. The structure of pure acrylic emulsion modified by inorganic nanoparticles was characterized by FT-IR and the results showed that inorganic nanopartilces had been reacted with monomers by in-situ polymerization. XRD showed that the structure of pure acrylic emulsion was not affected by nanoparticles. The results of TG showed that the thermal decomposable temperature of pure acrylic emulsion modified by nano-SiO2 and pure acrylic emulsion modified by nano-TiO2 were 359℃and 366℃respectively and they were much high than pure acrylic emulsion (328℃) . The differential scanning calorimetry was employed to monitor the glass transition temperature (Tg) of pure acrylic emulsion and pure acrylic emulsion modified by nanoparticles and the results showed that the glass transition temperature of the latter were high than the former. These results proved that the thermal stability of pure acrylic emulsion modified by nanoparticles was higher than unmodified emulsion. UV-vis spectrum showed the ultra-violet resistance of pure acrylic emulsion modified by nanoparticles was better than pure acrylic emulsion. The laser particle size analysis showed that when the amount of nanoparticles was 1%, the average particle size was 259nm and the emulsion possesses higher thermal stability, waterproof ability and excellent ultra-violet resistance compared to the pure acrylic emulsion.
Keywords/Search Tags:inorganic nanoparticles, surface modification, emulsion polymerization, composite latexes, property
PDF Full Text Request
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