Preparation and thermal properties of chemically prepared nanoporous silica aerogels
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This work focuses on the dependence preparation conditions—structure—physical properties of hydrophobic silica aerogels, all of them prepared under subcritical drying conditions (70 °C and 0.4 atm.), thus aiming at potential application as case insulation filling in heat pumps. The so prepared, millimeter scaled nano-porous hydrophobic silica aerogel granules were analyzed with standard electron microscope and atomic force microscopy, IR spectroscopy, UV/Vis spectroscopy, differential scanning calorimetry and thermal conductivity measurements. The physical properties of the aerogels were compared with commercial aerogel granules. A method for contact angle measurement of micro-droplets situated on the silica granules was proposed to quantify the level of their hydrophobicity.
KeywordsSilica aerogels Sol–gel Thermal properties Hydrophobization
The authors acknowledge the financial support from Project FP7 EFFiHEAT. Thanks are due to K. Balashev and M. Spassova for experimental help.
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