Study On Zinc Oxide/Polymer Composite Particles With Antibacterial Property

Zinc oxide particles have exhibited antibacterial, absorbable and shielding ultraviolet functions. ZnO/polymer composite particles prepared by special polymerization process can improve the dispersibility of ZnO particles. In addition, it can integrate the eminent abilities of inorganic and organic materials into the composite materials.In this thesis, preparation, properties and applications of ZnO nanoparticles, surface modification of nanoparticles, preparation of inorganic-polymer composite nanoparticles, emulsion polymerization in the existence of nanoparticles as well as the property and application of inorganic antibacterial materials were expatiated. Zinc oxide particles were prepared by homogeneous precipitation method and modified with different methods. On the basis of above process, ZnO/polymer composite particles were prepared by in-situ polymerization and soapless emulsion polymerization. The resulting zinc oxide particles and composite particles were characterized by transmission electron microscopy(TEM), scanning electron microscopy (SEM), infrared spectrum (FT-IR), nuclear magnetic resonance spectroscopy(NMR), gel permeation chromatography(GPC), X-ray diffraction, laser particle size analyzer, dynamic contact angle analyzer, thermogravimetric analyzer (TGA), specific surface area analyzer, UV-VIB spectrophotometer, X-ray photoelectron spectroscopic analysis(XPS), atomic absorption analysis and so on.It was showed that the particles prepared by homogeneous precipitation method were small and presented fine distribution. The size of particle is influenced by ratio of reaction partners, surfactant, reaction temperature, reaction time and post-treatment process. ZnO particles were modified by PMMA in aqueous solution, which can enhance dispersion of particles in aqueous system. With modified ZnO particles as seeds, soapless emulsion polymerization was carried out. The PSt oligomers were absorbed and trapped on the surface of ZnO particles. Consequently, ZnO/PSt composite particles were synthesized.The results showed that silane coupling agent can react with–OH groups on the surface of ZnO particles. The organic chains grafted on the particle surface improve the dispersibility and hydrophobic of particles. Further, with modified ZnO particlesas seeds, ZnO/PMMA composite particles were prepared by in-situ emulsion polymerization. The surface of modified ZnO particle was acted as locus of emulsion polymerization and composite particles were synthesized. In the course of polymerization, the conversion of MMA increased with progress of the polymerization. The percentage of grafting polymer onto the surface increased at the initial stage of the copolymerization, however, the grafting efficiency decreased with progress of the polymerization. Grafting efficiency can be increased by adding crosslinker(DVB).It was found that ZnO nanoparticles and ZnO/polymer composite particles demonstrated perfect antibacterial property. The results indicate that PVC sheet and emulsion-formed film added composite particles have obvious antibacterial effects and display prolonged antibacterial effects. The antibacterial mechanism of composite particles was further studied.