Proteus software

The study of the thermal properties of the samples was carried out by differential scanning calorimetery (DSC) by the Netzsch 214 Polyma (Selb, Germany), in an air atmosphere, with a heating rate of 10 °K/min and with a cooling rate of 10 °K/min. The samples were heated from 20 to 220 °C and then cooled to 20 °C twice. The average statistical error in measuring thermal effects was ±2.5%. The enthalpy of melting was calculated using the NETZSCH Proteus software. The mass of all samples encapsulated into aluminum pans was kept at about 7 mg. The thermal analysis was carried out according to the standard technique [63 ].
The crystallinity degree of the samples, $$\chi$$ , was defined from the first scan as: $$\chi =\frac{\Delta \mathrm{H}}{{\mathrm{H}}_{\mathrm{PHB}}}\times 100\%$$
where $$\Delta \mathrm{H}$$ is melting enthalpy and $${\mathrm{H}}_{\mathrm{PHB}}$$ is the melting enthalpy of the ideal crystal of the PHB, 146 J/g [64 (link)].

The melting temperatures of obtained conjugates were estimated from endothermic peaks in differential scanning calorimetry (DSC) curves. The DSC curves of conjugates were obtained using a DSC 214 Polyma (Netzsch, Selb, Germany) heat flux-type calorimeter. Measurement control and data analysis were performed with Proteus software (Netzsch, Selb, Germany). Samples for the DSC measurements were sealed in 40-ll standard aluminum crucibles with a single hole punched in the lid. The total mass of a sample was between 4 and 6 mg. An empty crucible of the same type was used as a reference. The DSC cell was purged with a stream of high-purity nitrogen (99.999%) at a rate of 25 cm³ min⁻¹. DSC scans of all the samples were run at a heating rate of 5 °C min⁻¹ in the temperature range of 0–150 °C.

Stock materials and AJP inks used to fabricate the standard and AM melt wires, respectively, were subjected to DSC (Netzsch DSC 404 C Pegasus, Burlington, MA, USA) to evaluate the melting temperature of each material to validate the melting point of the actual stock material used, rather than relying on standard data. Alumina crucibles were used for determining the melting phase transitions of experimental samples. A four-step temperature program consisting of: (1) a ramp of 5 °C/min until a targeted temperature of 50 °C below the expected melting point of the material was reached; (2) a reduction of the ramp rate to 1 °C/min until a target temperature of 50 °C above the expected melting point was reached; (3) cooling the sample to the targeted temperature of 50 °C below the expected melting point of the material and holding for one-hour dwell to ensure that the DSC had truly come down to the targeted temperature; (4) repeating this process three more times This temperature profile was repeated for a total of four times, and the onset temperature was used as expected melting point for the printed melt wires. This analysis was completed using the last three runs with Proteus^® software (Netzsch).