Ft 900

Differential Scanning Calorimetry (DSC) analyses were performed in triplicate in a DSC Mettler 821 STAR^e system (Mettler Toledo, Milan, Italy) equipped with a Module and an Intracooler device for subambient temperature analysis (Julabo FT 900, Julabo, Seelbach, Germany), previously calibrated using Indium as a reference. Samples of 2–4 mg (Mettler M3 Microbalance) were scanned from 30 to 350 °C in a sealed aluminum pan with a pierced lid (capacity 40 μl) with a heating rate of 10 K min⁻¹ (nitrogen atmosphere, flux 50 ml min⁻¹). An analogous empty pan was used as a reference.
Simultaneous Thermogravimetric Analysis (TGA) was performed in a TGA/DSC1 Mettler STAR^e system (Mettler Toledo, Milan, Italy), previously calibrated using Indium as a reference. Samples weighing 3–4 mg in alumina crucibles with lids were scanned from 30 to 350 °C (heating rate 10 K min⁻¹) under nitrogen air atmosphere (flux 50 ml min⁻¹). For analysis of the single-crystal samples of the CD∙PTB complex, DSC measurements were recorded on a DSC XP-10 instrument (THASS: Thermal Analysis & Surface Solutions GmbH, Friedberg, Germany) with a sample heating rate of 10 K min⁻¹ and a dry N₂ purge gas with a flux of 60 ml min⁻¹. Thermogravimetry was performed under similar conditions on a TA-Q500 apparatus (Texas Instruments, Dallas, TX, USA). All measurements referred to above were carried out at least in triplicate.

Differential scanning calorimetry (DSC) analysis was performed with a Mettler STARe system equipped with a DSC821e Module and an Intracooler device (Julabo FT 900) for sub-ambient temperature analysis. The curves were recorded on about 3 mg of sample in 40 µL sealed aluminum pans with pierced lid (method: −30–250 °C temperature range; heating rate 10 K min⁻¹; nitrogen air atmosphere flux 50 mL min⁻¹). The instrument was previously calibrated with indium, as a standard reference. Each experiment was performed in triplicate. Thermo gravimetric analysis (TGA) was performed with a Mettler STARe system equipped with a TGA/DSC1. The curves were recorded on about 4 mg of samples in 70 µL alumina pans (method: 30–300 °C temperature range; heating rate 10 K min⁻¹; nitrogen air atmosphere flux 50 mL min⁻¹). The instrument was previously calibrated with indium, as a standard reference. Each experiment was performed in triplicate.
To simulate the lyophilization process, the DSC curves were recorded on about 30 mg of solution in 100 µL sealed aluminum pans with lid with a method that provides a first cooling step between 30 and −60 °C, an isothermal step at −60 °C, followed by a heating step between −60 and 60 °C, with a heating rate of 2 K min⁻¹.

The physical-chemical properties of all the freeze-dried products have been investigated as reported in [7 (link)]. In detail, the IR spectra in transmittance mode were obtained by a Spectrum One Perkin-Elmer spectrophotometer equipped with a MIRacle™ ATR device in the spectral region of 650–4000 cm⁻¹. Differential Scanning Calorimetry (DSC) analysis was performed by Mettler STARe system equipped with a DSC821e Module and an Intracooler device (Julabo FT 900) for sub-ambient temperature. The residual humidity was investigated by Thermo Gravimetric Analysis (TGA) with a Mettler STARe system equipped with a TGA/DSC1.

DSC experiments were conducted on a DSC2 (Mettler Toledo, Columbus, OH, USA), equipped with an intracooler (Julabo FT900, Seelbach, Germany) calibrated with an Indium standard before use. The weight of the DSC samples was around 5 mg. Samples were first heated from −20 °C to 190 °C at 10 °C/min and kept for 1 min at 190 °C, then cooled to −20 °C at 10 °C/min, kept for 1 min at −20 °C, and finally heated to 190 °C at 10 °C/min. Melting temperatures (T_m) and enthalpies (ΔH_m), as well as crystallization temperatures (T_c) and enthalpies (ΔH_c), were calculated from the second heating and cooling curves, respectively. Crystallinity (X_c) of the PHB phase in the blends was determined by applying the following expression: $$X_c(\%)=\frac{\Delta H_m}{\Delta H_m^0\times w_{PHB}}\times 100$$
where ΔH_m (J/g) is the melting enthalpy of the polymer matrix, ΔH⁰_m is the melting enthalpy of 100% crystalline PHB (146 J/g) [33 (link)], and w_PHB is the polymer weight fraction of PHB in the blend.

DSC measurements were conducted to characterize the solid-state of crystalline and amorphous samples. Samples (2 to 5 mg) were packed into standard aluminium crucibles (40 μL) with pierced lids. The samples were analysed with a DSC823e instrument (Mettler-Toledo, Greifensee, Switzerland) equipped with a cooling system (Julabo FT 900, Seelbach, Germany). Nitrogen (50 mL/min) was used as a purge gas. Equilibration at 25 °C for 3 minutes was followed by linear heating with a heating rate of 10 °C/min. Measurements were made in triplicate. Thermal events were analysed using the STARe software (Mettler-Toledo, Greifensee, Switzerland).

GG/RC-33 IP, formed in the dialysis bag in presence of 10 mg/mL RC-33, was dried at 50 °C for three days and subjected to a solid-state characterization in comparison with GG and RC-33.
Differential scanning calorimetry (DSC) analysis (10–300 °C, heating rate β = 10 K min⁻¹, nitrogen air atmosphere (flux 50 mL min⁻¹)) was performed by means of Mettler STAR^e thermal analysis system, version 9.30 DSC821^e (Mettler Toledo, Milan, Italy), equipped with an Intracooler device for sub-ambient temperature analysis (Julabo FT 900). Three replicates were performed for each sample.
Thermogravimetric analysis (TGA) (30–300 °C, heating rate β = 10 K min⁻¹, nitrogen air atmosphere (flux 50 mL min⁻¹), temperature range) was carried out by means of a Mettler STAR^e system (Mettler Toledo, Milan, Italy). Three replicates were performed for each sample.
Fourier-transform infrared spectroscopy (FT-IR) spectra were recorded using a FT-IR spectrophotometer (Perkin Elmer Spectrum One, Monza, Italy) with a single reflection attenuated total reflectance (ATR) accessory (PIKE MIRacle™). Approximately 5 mg of each sample (RC-33, GG and RC-33/GG IP) were placed on ATR crystal of ZnSe and pressed down to the crystal. The scanning range was 650–4000 cm⁻¹ and the resolution was 4 cm⁻¹.