Dsc 204 f1 phoenix calorimeter

DSC experiments were carried
out using a Netzsch DSC 204 F1 Phoenix calorimeter. The samples were
investigated in 40 μL of aluminum crucibles with pierced lids.
The rate of temperature change was 5 K·min⁻¹ in the temperature region 203 to 332 K (218 to 405 K for TBAB).
The behavior of eutectic solvents at higher rates (10 K·min⁻¹) and lower rates (1 K·min⁻¹) has been studied. At the same time, no significant change in the
position and magnitude of the peaks was observed. All samples were
first cooled and then heated. A total of one cooling and heating cycle
was performed. The presented data were obtained on a heating cycle.
FT-IR spectra of the DESs as well as pure NA were recorded using
a Bruker Tensor 27 spectrometer (Bruker, USA) with an ATR accessory
and OPUS software (Bruker, USA). The following operating parameters
were used: spectral range 4000–550 cm^–1,
resolution: 4 cm^–1, number of sample scans: 256,
number of background scans: 256, and slit width: 0.5 cm. An 831KF
Coulometer (Metrohm, Switzerland) was used for the determination of
water in DESs.

¹H NMR spectra were recorded at 25 °C in CDCl₃ or DMSO-d₆ on an Agilent 400 MHz DD2 spectrometer. The values of dn/dc for copolymers were determined using a BI-DNDC differential refractometer (Brookhaven Instr. Corp., Holtsville, NY, USA) at 30 °C in the concentration range of 1–15 mg/mL. The concentrations of monomers in reaction mixtures were measured by HPLC using a Shimadzu Prominence chromatographic system equipped with refractometric and matrix UV detectors, a thermostat and a Kromasil 100–5-C18 4.6 × 250 mm column. Acetonitrile was used as an eluent, the flow rate was 0.9 mL/min, and the thermostat temperature was 55 °C.
Molecular weights and molecular weight distributions of polymers were determined by GPC using a Chromos LC-301 instrument with an Alpha-10 isocratic pump, a Waters 410 refractometric detector and two exclusive columns, Phenogel 5 µm 500A and Phenogel 5 µm 10E5A, from Phenomenex (with a measurement range from 1 k to 1000 k); tetrahydrofuran was used as an eluent. Polystyrene standards were used for calibration.
Differential scanning calorimetry (DSC) was performed for polymer samples (ca. 10–15 mg in an aluminum pan) under dry argon flow on a DSC 204F1 Phoenix calorimeter (Netzsch, Selb, Germany) equipped with CC 200 controller for liquid nitrogen cooling. The heating and cooling rates were 10 °C/min and −10 °C/min, respectively, between −80 °C and 80 °C.