| Summary: | 碩士 === 明志科技大學 === 化學工程研究所 === 99 === In this research, silver nanoparticles were prepared by chemical reduction using polyacrylic acid, polyvinylpyrrolidone and polyvinyl alcohol as protective agent. The effects of the reaction time and the concentrations of protective agent, precursor and reducing agent , on the size of ultrafine particles were investigated by UV/Vis ,TEM, and DLS analyses. Obtained under different conditions, the size and the optical properties of silver nanoparticle were different. Synthesis of silver nanoparticles under the optimal process, a surface plasmon peck is observed at around 400 nm, characteristic of the Ag nanoparticles and confirmed silver ions reduction to zero-valent silver in the aqueous phase .The size of nanoparticles was about 8 ~ 30 nm by TEM analysis.
Experimental results show that the PAA-Ag particle size is small, PVP-Ag particle size is average , and PVA-Ag particle size is unstable. Adding appropriate polymer and precursor content will decrease particle size, but higher concentration of them will increase particle size. The particle size also decreases with the increasing the reducing agent content. The optimal condition to prepare the small and narrow distribution size of silver nanoparticles is that the precursor concentration is 2.5x10-4M , reducing agent concentration is 6x10-4 M , the reaction time is 60 minutes , and adding appropriate content of protective agent .
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