Dsc 60 calorimeter

The thermal stability of PCL and PHBV microparticles was investigated with a TGA209 thermobalance (Netzsch-Gerätebau, Selb, Germany) using 5 mg of sample into platinum crucibles. The thermogravimetric analyses (TGA) were held under dynamic N₂ atmosphere with a flow rate of 50 mL·min⁻¹. Temperature ranged from 25 to 600°C, following a constant heating rate of 10°C·min⁻¹.
Differential scanning calorimetry (DSC) curves were obtained in a DSC-60 calorimeter (Shimadzu, Kyoto, Japan) using aluminum crucibles with 5 mg of sample, under dynamic N₂ atmosphere with a flow rate of 50 mL·min⁻¹. Temperature ranged from −120 a 250°C, with a constant rate of 10°C·min⁻¹, according to the particular characteristics of each material. The equipment was previously calibrated with indium (m.p. = 156.6°C; ΔH_melting = 28.54 J·g⁻¹) and zinc (m.p. = 419.6°C). Thermograms provided information about thermal behavior changes of the studied materials [16 , 17 (link)].

The thermal properties of PHB were determined using the DSC-60 calorimeter (Shimadzu, Kyoto, Japan). Approximately 2.0 mg of extracted PHB was exposed to a temperature profile over 24 °C to 300 °C at a heating rate of 10 °C/min and under nitrogen atmosphere at a flow rate of 50 mL/min. The melting temperature (Tm), glass transition temperature (Tg), and melting enthalpy (∆H_m) of PHB were calculated by subtracting the baseline in the OriginPro software (OriginLab Corporation, Northampton, MA, USA), which consists of the minimum endotherm peak for T_m and the ratio between the area of the endotherm and the PHB mass for ∆H_m. The degree of crystallization (Xc) (4) was determined using the equation below: ${\mathrm{X}}_{\mathrm{c}}(\%)=\frac{\Delta {\mathrm{H}}_m}{\Delta {\mathrm{H}}_m^0}\times 100$
where, $\Delta {\mathrm{H}}_m^0$ is the melting enthalpy for 100% PHB crystallinity (146.6 J/g), and $\Delta {\mathrm{H}}_m$ is the melting enthalpy calculated by the DSC thermograms [41 (link)].

Accurately weighed samples of about 2 mg of each WIF-TRB and WIB-FLZ mixtures were analyzed in crimped aluminium pans (Shimadzu DSC-60 calorimeter, Japan). Operating conditions were 10 °C min⁻¹ of heating rate (25 to 350 °C) and nitrogen flow at 50 mL min⁻¹.

PXRD patterns were acquired using an X-ray diffractometer (MiniFlex 600; Rigaku, Tokyo, Japan), with a CuKα radiation source (λ = 1.5406 Å) at 40 kV and 15 mA. Each PXRD measurement was conducted over a 2θ range of 4–40°, with a step size of 0.02° and scan rate of 10°/min.
DSC analysis was performed using a DSC-60 calorimeter (Shimadzu, Kyoto, Japan). Each sample (2–3 mg) was placed on an alumina pan (with a blank pan used as a reference) and scanned from 30 to 250 °C at a heating rate of 10 °C/min in a nitrogen atmosphere (N₂ flow rate: 50 mL/min).
The temperature-dependent weight change was determined using a TGA instrument (N-1000; Scinco, Seoul, Korea). Specifically, 10 mg of each sample was loaded in a platinum holder and heated from 25 to 800 °C at 10 °C/min under nitrogen purging conditions.
A Spectrum Two^® attenuated total reflectance (ATR)–FTIR spectrometer (Perkin Elmer, Waltham, MA, USA) was used to acquire infrared (IR) spectra of various specimens in the solid state. Each spectrum was collected in a wavenumber range of 4000–450 cm⁻¹ with a resolution of 8 cm⁻¹.
Proton nuclear magnetic resonance (¹H NMR) spectra were recorded on a JEOL ECS 400 MHz NMR spectrometer. Each sample was dissolved in deuterated dimethyl sulfoxide (DMSO-d6) for analysis and chemical shifts for proton are reported in parts per million (ppm) downfield from tetramethylsilane.