2.2. Development of hydrophobic recycled cellulose aerogels
The aerogels in Section 2.1 are used to develop hydrophobic recycled cellulose aerogels. For hydrophobic coating, two different coating methods: physical and chemical, are used. In the physical coating method, a commercial water repellent spray (ReviveX® Nubuck) is used to spray onto the dried aerogel from a distance of 15 cm and then left to dry for one day at room temperature. In the second method, the chemical method, the recycled cellulose aerogelisplacedina big glass bottle.Asmall openglass vial containing methyltrimethoxysilane (MTMS) is added into the glass bottle. Then,the glass bottle is capped and heated in an oven at 70 ◦C for 2 h for the silanation reaction. Thereafter, the coated sample is placed
in a vacuum oven to remove the excess coating reagent until the pressure reaches 0.03 mbar. MTMS is chosen as the coating agent because it is cheap, commonly used for fabrication of hydrophobic and oleophilic aerogels; and the coating process is simple