2.5.1. Determination of Dispersion Stability

The average particle size and polydispersity index (PDI) of the dispersions were measured by dynamic light scattering (DLS) at room temperature using Zetasizer Nano ZS90 of Malvern Instrument and Equipment Company, Malvern, UK. In order to test the storage stability, all dispersions were stored in closed bottles and stored at room temperature.

#### 2.5.2. Fourier-Transform Infrared Spectroscopy (FTIR)

The synthesized polymer was analyzed by TENSORII Fourier-transform infrared spectrometer produced by BRUKER company in Germany. The attenuated total reflection (ATR) mode was used for infrared testing of WPU-SS samples. The spectra obtained were recorded in the range of 4000–500 cm<sup>−</sup>1.
