Uatr two ftir spectrometer

The FTIR spectra of the native λ-CAR powders were obtained using a PerkinElmer UATR Two FTIR spectrometer; 64 scans per spectrum; nominal resolution: 2 cm⁻¹; scan speed: 0.2 cm·s⁻¹; apodization: strong; source: MIR (8.000–30) cm⁻¹; detector: MIR TGS (15.000–370) cm⁻¹; the background was subtracted for each sample and a baseline correction was applied. All the spectra were recorded in the 4.000–450 cm⁻¹ region, although only the 1.500–500 cm⁻¹ area was used for the spectral analysis.

FTIR spectroscopy was done to identify and quantify functional groups for the aging characterization of the TPC and PPC-modified asphalt binders. A PerkinElmer UATR Two FTIR spectrometer working in attenuated total reflection (ATR) mode was used with an accumulation of 64 scans in the 400–4000 cm^–1 range. Binder samples were dissolved in tetrahydrofuran at a concentration of 10% w/v. ¹H NMR analysis was conducted on a Bruker 400 MHz NMR. The binder samples (about 20 mg) were dissolved in deuterated chloroform (CDCl₃) and placed in 5 mm NMR tubes. FTIR and NMR were performed twice for each binder, and average results were reported.

Scanning electron microscopy (SEM) was used to analyze the morphology of the microparticles at 100X and 1000X magnifications. The dry powder of the microparticles was placed onto metal plates and sputter-coated with gold (Thermo Fisher Scientific, Waltham, MA, USA). The mean hydrodynamic diameter and size distribution of the microparticles suspended in water was measured with dynamic light scattering using a Microtrac S3500 (Microtrac Inc., Montgomeryville, PA, USA). The spectrum of the synthesized chitosan and microparticles was obtained with Fourier transform infrared spectroscopy (FTIR) using a Perkin Elmer UATR Two FTIR Spectrometer in the 4000–500 cm⁻¹ wavenumber range with 40 accumulated scans. This technique was used to identify the functional groups present in these structures. Thermogravimetric analysis (TGA) was used to determine the thermal stability of the chitosan and the microparticles obtained using the spray drying technique. This analysis was developed using a Cahn-Versatherm thermogravimetric analyzer (Thermo Fisher Scientific, Waltham, MA, USA) with a sensitivity of 0.1 μg at a heating rate of 10 °C/min under a nitrogen atmosphere (100 mL/min). The temperature was scanned from room temperature to 600 °C.