Density measurements. Densities were measured by a DMA-
38 vibrating U-tube densitometer (Anton Paar Co.). According to
the manufacturer the precision and reproducibility of the apparatus
are
±0.001 g/cm3 and
±0.0002 g/cm3, respectively. The U-tube
densitometer apparatus was calibrated using de-ionized, degassed
water and ambient air. After setting the desired temperature, the
measurements were replicated two times and the average of replicates
was reported. A BP 310S digital balance was used to weigh
the materials with an accuracy of
±0.001 g.