| Summary: | 碩士 === 國防大學中正理工學院 === 應用化學研究所 === 93 === Polystyrene（PS）oligomers prepared for depositing metallic nanoparticles were synthesized using the radical polymerization based on styrene/potassium persulfate/water system in the presence of carbon tetra-bromide. Their molecule weights ranging between 2000 and 10000 g/mole could be tailor-made by means of changing the amount of the chain transfer agent. When resultant PS oligomer latex and nobel metal ion solution were heated and followed by mixing together without extra-added reductant, metal nanoparticles deposited upon the polymer chain ends could readily obtain. Observed result from GC-MS diagram, a possible mechanism proposed by our work is that the functional sulfate groups that are normally bonded with the PS chain ends could react with metal ions to undergo redox-reaction so as to form nanosized organic-metal composites when they are surrounded by the strong reducible metal ions. The aromatic unit existing on PS oligomer chain can reflect in its hydrophobic property which is apt to coagulate nanosized organic-metal composites. The longer the aromatic chain length of the PS oligomers, the stronger the hydrophobic property. Sulphonation, used wieldly for the solubilization of insoluble compounds, was also carried out to improve the hydrophilic property of PS oligomers. Result showed that sulphonated PS oligomers do greatly soothe coagulating of the organic-metal composites. Deposition of metal nanoparticles upon the surfaces of microspheres that were synthesized by the emulsifier-free emulsion polymerization was also successfully obtained. Observed the result from TEM images, it seemed that extending deposition time is prone to coagulate metal nanoparticles with the one formed in the vicinity of themselves and therefore makes itself bigger. Accordingly, the particle size of the deposited metal nanoparticles could be tailor-made by means of changing the deposition time.
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