| 摘要: | 複合材料是由基材和填料相互混合而成，因此材料之複合效應為各組成材料及其所形成之介面相互作用下的綜合結果。根據填料種類不同，複合材料之特性也會隨之改變。除了典型複合材料，多孔材料也可視為一種基材與空氣混合之複合材料。根據材料內部孔隙之分布與大小，可發展出許多不同之應用。
本研究之目的為製備高導熱性之PDMS多孔複合材料。首先在製備複合材料時，選擇石墨作為填料，使用機械震盪分散法將其均勻分散於溶液中，再與PDMS做混合即可製備出石墨/PDMS複合材料。在製備多孔結構之部分，採用糖浸法；將石墨/PMDS混合溶液滲透入多孔隙之模具內部後固化，再去除模具即可得到石墨/PDMS多孔複合材料。
使用儀器量測多孔複合材料之基礎性質與熱擴散係數，將其與材料參數結合可得孔隙率與熱傳導係數。在分析上結合複合材料之基本參數並使用不同理論數值模型來預測材料之熱傳導係數，最後將不同模型之計算結果與實驗量測數值做出比較，探討石墨填充濃度與孔隙率對熱傳導性質之影響。結果顯示，增加石墨填充濃度可有效增加材料之熱傳導特性，且大致與填料濃度成正比。在溫度343K左右時，由於試片之結構強度不足，因此在高溫環境下可能產生形變，進而使實際量測數值產生誤差，所以無法利用模型來有效的預測試片之熱傳導係數。
;The composite material is formed by mixing the base material and the filler, so the composite effect of the material is the comprehensive result of the interaction of the constituent materials and the interface formed by them. Depending on the type of filler, the characteristics of the composite material will change accordingly. In addition to typical composite materials, porous materials can also be regarded as a composite material in which a substrate and air are mixed. According to the distribution and size of the pores inside the material, many different applications can be developed.
The purpose of this research is preparing PDMS porous composites with high thermal conductivity. First, when preparing the composite material, choose graphite as the filler, use the mechanical vibration dispersion method to uniformly disperse it in the solution, and then mix it with PDMS to prepare the graphite/PDMS composite material. In the preparation of the porous structure, the sugar leaching method is used. The graphite/PMDS mixed solution is penetrated into the porous mold and then cured, and then the mold is removed to obtain the graphite/PDMS porous composite material.
Use instruments to measure the basic properties and thermal diffusivity of porous composite materials, and combine them with material parameters to obtain porosity and thermal conductivity. Analyze the basic parameters of composite materials and use different theoretical numerical models to predict the thermal conductivity of the material. Finally, compare the calculated results of different models with experimental measured values to explore the influence of graphite filling concentration and porosity on the thermal conductivity properties.
The results show that increasing the graphite filling concentration can effectively increase the thermal conductivity of the material, and it is roughly proportional to the filler concentration. At the temperature of 343K, due to the insufficient structural strength of the test piece, deformation may occur in a high-temperature environment, which may cause errors in the actual measured value. Therefore, the model cannot be used to effectively forecast the thermal conductivity of the piece. In the future, it is planned to reduce the porosity of the composite material and increase the filler concentration to increase the thermal conductivity and stability of the material. |
