| Summary: | 碩士 === 國立聯合大學 === 化學工程學系碩士班 === 102 === The study is probing into the influence of polyvinylpyrrolidone (PVP) for silver particles’ formation in silver-copper replacement reaction, and fabricating composite by mixing silver-copper powders into resin, observing the change of thermal conductivity. By changing the content of silver nitrate, the content of PVP, reaction time, molecular weight of PVP, the result shows that when the molar ratio of silver nitrate to copper powder is 1:13, the reduction rate of silver particles could be controlled, and forming dendritic structure silver which has obvious branch structure; by adding 15 wt. % PVP, the dendritic structure silver formed larger and obvious branch structure; when reaction time is 30 minutes, there are enough time to reduction silver particles, and forming dendritic structure silver which has obvious branch structure; when the molecular weight of PVP is 8000 g/mol, the dendritic structure silver form obvious branch structure. Besides, we could find the acicular structure is cupric oxide (CuO) by XRD.
Moreover, we observe influence of thermal conductivity by changing the content of silver-copper powders and adding different molecular weight of PVP in composite. The result shows that when the content of filler is higher, the thermal conductivity of composite is higher; when the content of silver-copper powders which adding PVP in 8000 g/mol is 60 wt. %, the composite has much better thermal conductivity, is 0.5956 W/ m•K; To understand the influence of the molecular weight of PVP, when the molecular weight of PVP is 8000 g/mol, the dendritic structure silver form obvious branch structure and has much more conduction routes to rise thermal conductivity, the volue of thermal conductivity is 0.5956 W/ m•K.
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