Sta 449 f5 thermal analyzer

The thermogravimetric properties of pitches and fibers were measured using a STA 449 F5 thermal analyzer (Netzsch, Bavaria, Germany). The peak temperature (T_p, °C), weight uptake (ΔW, %) and enthalpy change (ΔH, J) of PFs were collected from their TG−DSC curves in the air mood with a heating rate of 1 °C/min to 600 °C. The decomposition temperature (T_d, °C), coking values (CV, %) at 1000 °C and ΔH of SFs were collected from their TG−DSC curves in the nitrogen mood with a heating rate of 5 °C/min to 1000 °C.

UV-Vis spectra were recorded on a UH 5300 UV-vis spectrometer (Hitachi, Tokyo, Japan) at room temperature. Data were collected in the range of 200–800 nm, with the band width of 1 nm and with the data interval of 0.5 nm.
IR spectra were collected on a Nicolet 380 Fourier transform infrared spectrometer (Thermal Scientific, Waltham, MA, USA). Spectra were collected in the 4000−400 cm⁻¹ spectral range, with a resolution of 2 cm⁻¹ and with 32 acquisitions as co-added scans.
XRD data were obtained by using an Ultima IV X-ray powder diffractometer (Rigaku, Tokyo, Japan) with Cu-Kα irradiation (λ = 1.5418 Å). The operation conditions of analysis were a voltage of 40 kV, current of 40 mA, scanning range 5–30°, and scan rate of 0.02° min⁻¹.
Thermogravimetric analysis was applied on a STA449 F5 thermal analyzer (NETZSCH, Selb/Bavaria, Germany). Samples 2.0 to 2.5 mg were heated from room temperature to 590 °C at the heat rate of 10 °C min⁻¹.