*2.3. Characterization*

A Fourier transform infrared spectrometer (FT-IR; Bruker, Equinox 55, Mannheim, Germany) was used to record the infrared spectra of raw materials and products in the range of 4000–400 cm−1. The morphology of the products was observed with a scanning electron microscope (SEM; Hitachi, S-4800, Tochigi, Japan). The crystal structure of the sample was examined by X-ray diffraction (XRD; Bruker, D8 ADVANCE, Mannheim, Germany). The thermal stability of the products was analyzed by thermogravimetric analysis (TGA; Mettler, TGA/DSCI, Greifensee, Switzerland) from 35 to 800 ◦C with heating rate 10 ◦C min−<sup>1</sup> under nitrogen atmosphere.

**Scheme 2.** The mechanistic pathway for synthesis of superabsorbent composite (SAPC).
