2.3. Structural observations of BRS
2.3.1. Light microscopy and polarising microscopy
BRS samples were dissolved in glycerol (50% concentration) and
observed under a microscope (Vanox BHS-2, Olympus Corporation,
Japan) using both natural and polarised light.
2.3.2. Scanning electron microscopy (SEM)
Particles of BRS powder were scanned, using a S3700N scanning
electron microscope (Hitachi, Japan). Samples were fixed on an
objective table coated with platinum (10–20 nm thickness).
2.3.3. X-ray diffraction (XRD)
Cu Ka radiation was used to scan BRS samples over the 2h = 4–
60 range, with a step interval of 0.04, a scanning rate of 17.7 s per
step, a voltage of 40 kV, and a current of 40 mA. The D8 ADVANCE
X-ray diffractometer from Bruker Corporation (Germany) was used
for the XRD analyses.
2.3.4. Infrared spectroscopy
BRS samples were pressed in KBr. An infrared spectrometer
(VECTOR33, Bruker Corporation, Germany) was used to scan the
samples from 4000 cm1 to 400 cm1 of the infrared region.