| Summary: | 碩士 === 國立雲林科技大學 === 化學工程與材料工程系碩士班 === 101 === In this study,in order to prepare the core-shell structure between with organic polymer and inorganic metal.The core was polystyrene,which was preparation by dispersion polymerization,and we take of 2,2-azobisisobutyronitrile ( AIBN) as initiator and Polyvinylpyrrolidone (PVP) as stabilizer added in different proportions to find the suitable ratio of particle size as we required. Under appropriate conditions,preparation the monodispersed PS microspheres, it have almost monodisperse of radius in every batch of synthesis. The functional group were anchored on the surface of organic microsphere by the copolymerization of silane coupling agent 3-trimethoxysilyl propryl methacrylate(TSPM), the trimethoxysilyl group may be hydrolyzed to trihydroxysilyl groups on the PS microspheres,and use Si≡(OH) 3 to formation Si-O-Ni with covalent bonding.The samples were characterized by FTIR to confirmed that there are Si-OH and C=O groups copolymer. Thermal gravimetric analysis(TGA) curves shows the nickel coated microspheres''s weight loss was inversely proportional to contents of silane coupling agent.The micrometer-sized core-shell particles (diameter 4–6μm) was fabricated by electroless plating technique .The organic microspheres were then coated with nickel(Ni) metal by electroless plating.To make sure the bondage between organic polymer and inorganic metal,we take ball mill tests with different TSPM weight ratio.
After the nickel have plated on the surface of PS microsphere, the gold(Au) was plated on the surface of nickel metal. The purpose of the gold plating was to prevent the oxidation of nickel by air or any other oxidant.We also use cationic surfactant、anionic surfactant and nonionic surfactant to improve the surface coating defects. The XRD pattern indicate the Au peaks and without Ni peaks,it''s describe that the gold layer is cover the nickel layer,and we check it with EDX ,the spectra supported the results from XRD analysis stated above. Magnetic measurements were performed using SQUID magnetometer at room temperature.The saturation magnetization (M s )of nickel layer of hydrazine as reducing agent is larger than sodium hypophosphite as reducing agent,and it shows that is ferromagnetic materials at room temperature. The silane bridge with nickel was proven to be durable by ball mill tests,after the ball mill the samples has lost their integrity as spheres.
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