Preparation Of Core-shell Structure Organosilicon Modified Acrylic Composite Emulsion And Study On The Nano-modification

Organosilicon modified acrylic composite emulsion with core-shell structure was prepared by seeded emulsion polymerization. MMA,BA,AA, D4, YDH-570 and YDH-151 were used as the main raw materials, and proper emulsifier, initiator and other assistants were selected. The TEM showed that the emulsion particles had obvious core-shell structure,the inner core layer was acrylate polymer and the outer shell layer was organosilicon polymer. Many factors could affect the properties of the product emulsion. The experiments' results showed that,the kind and dosage of emulsifiers, the using rate of hard and soft monomers,the dosage of organosilicon, and the polymerization processs could strongly affect the emulsion polymerization and properties of the product emulsion. Considering both the cost and the properties factors, proper recipe and process were presented. The surfaces of nano-TiO2 particles were changed from hydrophilic to hydrophobic and active organic functional groups were grafted to the particles' surfaces by being modified with silane coupling agents. The modified nano-particles could stay stably and agglomeration was avoid.Nano-TiO2/organosilicon modified acrylic composite emulsion was obtained by in-situ polymerization. The result of TEM showed that there were two kinds of emulsion particles existed in the emulsion: One kind of particles were core-shell structure organoasilicon modified acrylate emulsion particles with acrylate polyer core and organosilicon polymer shell, and the other kind of particles were inorganic/organic multiplayer core-shell structure particles, which were formed by the way of the polymers grafted to the surfaces of nano-TiO2 particles. The emulsion particle type could be controlled by the amount of emulsifier. The ultraviolet screener, sterilization and pollutant degrade functions of the composite emulsion were characterized. The result showed that these functions of nano-TiO2/organosilicon modified acrylic composite emulsion were excellent.In a short time,the rate of sterilization of composite emulsion contained 1 percnt TiO2 the reached 95%, and the degrade rate of formaldehyde of diluted emulsion reached 47%. The composite emulsion can be used as base material of slap-up environment protecting coating,which will has the function of environment cleaning.