Nicolet 380 ftir spectrometer

Fourier‐transform infrared spectroscopy was performed on a Nicolet 380 FT‐IR spectrometer (Thermo Fisher, USA) equipped with an attenuated total reflectance (ATR) accessory. The sample solution used for CD spectroscopy was also used for FT‐IR analysis. Prior to actual measurement, background spectra were obtained under nitrogen gas purging of the detector to minimize interference from other gases such as water vapor and/or CO₂. The spectral range collected was 400–4000 cm⁻¹. The resolution and scan number were 4 cm⁻¹ and 256, respectively. For analyzing peptide secondary structure, FT‐IR spectra were processed to the second derivative using OriginPro 8 software with 7‐point smoothing (OriginLab Corp., Northampton, MA, USA) as reported earlier.⁷⁷, ⁹⁷

The binder structure was analyzed by Fourier transform infrared (FTIR) spectrometry and thermogravimetric differential scanning calorimetry (TG-DSC). The binder was measured on a Nicolet 380 FTIR spectrometer (Nicolet 380, Thermo Fisher Scientific, Waltham, MA, USA) using the KBr disc technique. For FTIR measurement, 1 mg binder was mixed with 100 mg anhydrous KBr and was then compressed into thin disk-shaped pellets. The spectra were measured with a resolution of 4 cm⁻¹ between a wave number range of 4000 to 400 cm⁻¹. The thermal analysis of the binder was carried out using TG-DSC (STA449F3, Netzsch, Selb, Germany). The type of crucible of the TG/DSC pan was Al₂O₃. The sample chamber was purged with nitrogen gas at a rate of 30 mL/min. TG and DSC analyses were performed with a heating rate of 10 °C/min in the temperature range of 28 to 1200 °C. Scanning electron microscopy (SEM, Nova NanoSEM 450, FEI, Columbia, MD, USA) was used to observe the microstructure of binder particles and to gain further knowledge of the iron ore particle structure and morphology after bonding with the binder.

FTIR spectroscopy was used to examine the changes in the functional groups of CNCs obtained. The FTIR spectra were collected by using a Nicolet 380 FT-IR Spectrometer (Thermo Fisher Scientific, Hampton, NH, USA) in the transmittance mode. Five mg of powder samples of RF and CNC were dispersed in a matrix of KBr to be mixed and pressed into a pellet. The samples were analyzed in a spectral region between 4000 and 400 cm⁻¹ with a 2 cm⁻¹ resolution, while the obtained spectra were averaged over 32 scans.