The
powdery samples (1 g) in 10 MPa pressure were first pressed into
thin pellet and then the water droplet was dropped onto the pellet.
The contact angle against water on a horizontal surface of a pellet was
obtained. Fourier transforminfrared spectroscopy (FT-IR)was performed
on an Ominic System 2000 using KBr pellets. The thermogravimetry
analysis (TGA) was performed on Melttler Toledo 825e instrument at
50–900 °C with a program heating rate of 10 °C min−1 in a flowing air
atmosphere.