二氧化矽氣凝膠／酚醛樹脂奈米複合材料之熱傳導研究

隔熱、節能為近年來建材上的主要訴求，而氣凝膠的熱導率比起目前常用的隔熱建材都還要低，於建材應用上極具發展價值。本實驗以水玻璃(矽酸鈉)為前驅物製備二氧化矽氣凝膠粉末，並將之與液體酚醛樹脂混合製成複合物，藉由實驗量測及理論計算來了解液體酚醛樹脂對於氣凝膠粉末之密度、孔隙率及熱導率的影響。本實驗所製備的二氧化矽氣凝膠粉末的密度為0.35 g/cm3、孔洞體積為0.90 cm3/g以及孔洞直徑為4.5 nm，而粉末的熱導率為0.07 W/m-K。當氣凝膠粉末於複合物中的比例為50 wt%以上時，其樣品不再會被酚醛樹脂固化時所產生的水氣所影響而形成裂縫或孔洞。經實驗量測，酚醛樹脂的熱導率為0.28 W/m-K而添加氣凝膠粉末70 wt%的複合物為0.10 W/m-K，熱導率下降約64 %。且於大氣環境下進行熱重分析發現當二氧化矽氣凝膠粉末添加量提高至60 wt%時，酚醛樹脂與複合物之重量損失達30 %時兩者的溫度相差98 °C，當環境溫度為400 °C時其重量損失分別為51 %和22 %。因此，二氧化矽氣凝膠／酚醛樹脂奈米複合物的熱導率會隨著氣凝膠粉末的含量上升而下降，添加二氧化矽氣凝膠粉末可以有效增加酚醛樹脂的抗燃性。

關鍵字

二氧化矽氣凝膠；酚醛樹脂；奈米複合材料；熱傳導

並列摘要

In this study, we proceeded the theoretical and experimental research on thermal conductivities of silica aerogel/phenolic resin nanocomposites. The samples were prepared by mixing hydrophobic silica aerogel powder with with resol type liquid phenolic resin. The silica aerogel powder was synthesized from waterglass precursor via ambient pressure drying. The properties of the silica aerogel powder in this study were as follows: the density of 0.35 g/cm3, the pore volume of 0.90 cm3/g, the pore diameter of 4.5 nm and the thermal conductivity of 0.07 W/m-K. We found that the thermal conductivity of the nanocomposites decreases as the weight fraction of aerogel powder increases. When the weight fraction is 70%, the thermal conductivity ( 0.10 W/m-K ) is 64% lower than that of pure phenolic resin ( 0.28 W/m-K ). Thermogravimetric analyses shows that the addition of silica aerogel powder improves the flame retardance of phenolic resin in the air. The temperature of the nanocomposite ( aerogel powder: 60 wt% ) for 30% mass loss is 98 °C which is higher than that of pure phenolic resin. The percentage mass loss of pure phenolic resin and the nanocomposite ( aerogel powder: 60 wt% ) are 51% and 22% respectively at 400 °C.

並列關鍵字

Thermal conductivity ； nanocomposite ； Phenolic resin ； Silica aerogel

參考文獻

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國際替代計量

二氧化矽氣凝膠／酚醛樹脂奈米複合材料之熱傳導研究

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