Mass absorption
The dry sample was weighed on a Mettler Toledo XS 104 analytical balance and then placed in a 50 mL beaker filled with isopropanol. The beaker with the sample and isopropanol was placed in a desiccator, to which an oil pump was connected. The sample was degassed for 30 min. After this time, the sample in the isopropanol beaker was removed from the desiccator and beaker. Excess i PrOH was removed and weighed on an analytical balance. Each experiment was performed in 3 replications. Water absorption was calculated from the formula:
\begin{equation} A_{m}=\frac{m_{w}-m_{d}}{m_{d}}\times 100\%\nonumber \\ \end{equation}
where:
m w - mass of the wet air-weighed sample, g
m d - dry mass of the air weighed sample, g
A m - mass absorption,%