Sta449f3

The thermal analysis (STA449F3/STA449F3, NETZSCH, Hamburg, Germany) was used to analyze the thermal properties of synthetic polymers. Nitrogen was used as the protective gas, the heating rate was 10 °C/min, and the test temperature range was 25 °C to 1000 °C.

Fourier-transform infrared spectra (FT−IR) were recorded on a PerkinElmer Frontier (PerkinElmer, Waltham, MA, US) from 4000 to 400 cm⁻¹ with 32 scans at a resolution of 4 cm⁻¹. Proton nuclear magnetic resonance spectroscopy (¹H NMR) was obtained using a Bruker 300 MHz spectrometer (Bruker, Bremen, Germany) with CDCl₃ as the solvent. The transmittance of elastomers was characterized on a UV−Vis spectrophotometer (TU−1810, Beijing Puxi Instrument Factory, Beijing, China). Thermal gravimetric analysis (TGA) was performed on a synchronous thermal analyzer (STA449F3, Netzsch, Selb, Germany) by heating the samples from room temperature to 800 °C at a heating rate of 10 °C/min under the protection of a nitrogen atmosphere. Differential scanning calorimetry (DSC) measurements were conducted on a NETZSCH STA449F3 instrument (Netzsch, Selb, Germany) at a heating rate of 10 °C/min from −140 to 100 °C under a nitrogen atmosphere. Rectangular specimens (40 mm × 10 mm × 2 mm) were formed and used to test the mechanical properties of PDMS elastomers on a universal electronic tension testing machine (Instron 5944, Instron, Norwood, MA, USA) with a strain rate of 20 mm/min at room temperature. The self-healing process of the crack on the elastomer was observed using optical microscopy (WMP−6880, Wumo Optical, Shanghai, China).

The structure of the developed IL was determined by Fourier Transform infrared spectroscopy (FT-IR) and ¹H Nuclear Magnetic Resonance testing (¹H-NMR). In addition, the effects of regeneration on the molecular structure and thermal stability of cellulose were studied by FT-IR, an X-ray diffractometer (XRD) and thermal gravimetric analysis (TGA). A FT-IR spectrometer (Thermo Nicolet 360, Thermo Nicolet Corporation, Madison, WI, USA) with a resolution of 4 cm⁻¹ and spectral region of 500–4000 cm⁻¹ was used in the test. ¹H-NMR spectra of the IL were collected from a Bruker Avance-400 NMR spectrometer (Bruker Biospin GmbH, Karlsruhe, Germany) operating at 400 MHz. Before use, the synthesized IL was completely dissolved in the solvent of D₂O at room temperature. XRD data was collected in a scan mode with the scanning speed of 5°/min in the 2θ range between 5° and 60°. The pattern was Cu-Kα radiation (MiniFlex-2) with a voltage of 40 kV and a current of 30 mA. TGA curves were measured on a TG-DTA instrument (Netzsch STA 449F3, Netzsch Gerätebau GmbH, Selb, Germany). Approximately 5 mg of original or regenerated cellulose was weighed and heated from 30 °C to 550 °C (10 °C/min) with a nitrogen flow rate of 20 mL/min.