Pyris diamond

Determination of gelatinization properties of starch and flour samples were carried out using a differential scanning calorimeter (DSC) (Pyris Diamond, PerkinElmer, Waltham, MA, USA) equipped with an Intracooler 2P cooling system. Calibration was performed with indium and n-decan for a temperature range from +20 to +95 °C. Each sample was mixed with deionized water (flour: water ratio = 1:3), filled in DSC pans (20–35 mg) and hermetically sealed. After 2 min of equilibration at 25 °C, samples were heated to 95 °C at 10 K/min in a nitrogen atmosphere. The gelatinization onset (To), peak (Tp), and conclusion temperatures (Tc), and the enthalpy of gelatinization (ΔH) were determined using the Pyris software.

The morphology and detailed structure of VG was investigated by SEM (FEI Quattro S, acceleration voltage 5–10 kV, TEM (FEI Tecnai F20; acceleration voltage 200 kV); Raman spectroscopy (Horiba, LabRAM HR 800, 532 nm laser wavelength), XPS (Kratos Analytical Axis‐Ultra spectrometer with Al Kα X‐ray source). The thermal diffusivities (α) of the sample were measured using LFA 467 MicroFlash system (NETZSCH, Germany). The specific heat capacity of the sample evaluated by using a DSC (PYRIS Diamond, PerkinElmer, USA). The infrared (IR) photos were captured by using an infrared camera (Fluke, Ti400, USA).

Fourier transform infrared (FT-IR) spectrum of the products was recorded on a Magna-IR, spectrometer 550 Nicolet in KBr pellets in the range of 400–4000 cm⁻¹. Micrographs of HA powders were taken by using a field-emission scanning electron microscope (FE-SEM, TESCAN, Brno, Czech Republic). Powder X-ray diffraction (XRD) patterns were collected from a diffractometer of Philips Company (Amsterdam, The Netherlands) with X’Pert Pro monochromatized Cu Kα radiation (λ = 1.54 Å, operated on 35 mA and 40 kV current).
For microstructural studies, the porous scaffolds were frozen at −50 °C and cross-sectionally cut to small pieces by a sharp surgical blade. After gold sputtering, the cross-sections were observed by SEM. Pore size distribution of the porous scaffolds were supplied by Digimizer software. Thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG) were carried out with Pyris Diamond Perkin Elmer, under air atmosphere, at a heating rate of 10 °C/min, from room temperature to 1200 °C.

Thermogravimetric analysis of MET-PGA-, R1- and R2-derived films was performed using a thermogravimetric analyzer TGA/DTG Perkin-Elmer PyrisDiamond, equipped with gas station. Samples (3–4 mg) were placed in an open ceramic crucible and heated from 25 °C to 600 °C at a speed rate of 10 °C·min⁻¹, under nitrogen flow of 30 mL·min⁻¹. Before testing, samples were conditioned for 24 h at 25 °C and 50% RH. Thermal properties of MET-PGA-, R1- and R2-derived films were investigated by using a Q2000 T zero differential scanning calorimeter (DSC), TA Instrument (New Castle, DE, USA), equipped with a liquid nitrogen accessory for fast cooling. The calorimeter was calibrated in temperature and energy using indium. Dry nitrogen was used as purge gas at a rate of 30 mL·min⁻¹. Samples (3–4 mg) were weighed and placed individually in aluminum pans; an empty pan was then used as reference. DSC measurements were performed in double heating run; the first one, occurring from 50 to 200 °C, at 10 C·min⁻¹, could reproduce the thermal history of the samples. After an isothermal step of one min, non-isothermal crystallization experiments were performed by cooling the specimens up to −50 °C, at a rate of 10 C·min⁻¹. Finally, a second heating ramp from −50 °C to 250 °C at 10 °C·min⁻¹ was recorded. Before testing, the samples were conditioned for 24 h at 25 °C and 50% RH.

The thermal characteristics of GC_LP_L, GC_LP_H, GC_HP_L, and GC_HP_H, biocomposites with weight between 2–10 mg were recorded using a Perkin-Elmer Pyris Diamond differential scanning calorimeter. All the samples were lightly pressed into the bottom of the pan to ensure good thermal contact. Sealed DSC pans were used in the study. Triplicate samples were heated at a rate of 10 °C/min from 10 °C to 100 °C. Peak melting temperature (Tm) and heat of fusion data for the PCL component of the materials were determined using the built-in software of the DSC. The latter measurement was subsequently used to estimate the percentage crystallinity of PCL in the composites from the reported heat of fusion of 139.5 J/g for fully crystalline PCL (Burke, 1987 (link)). Indium was used as a standard.