2.6. Characterization of Bioactive Films Containing CuONPs or Bio-AgNPs

Thermogravimetric Analysis (TGA) were performed under nitrogen atmosphere in a TGA 550 thermobalance (TA Instruments, Toronto, ON, Canada). Samples were heated from room temperature up to 600 °C at a rate of 10 °C min⁻¹ under nitrogen. Derivative TGA curves (DTG) express the weight loss rate as a function of temperature and the temperature of the maximum rate of degradation (Td). Fourier-transform infrared spectroscopy (FTIR) characterization was performed on samples of the PHO films. The FTIR spectra were obtained on a Nicolet 5700 FTIR spectrometer (Thermofisher, Waltham, MA, USA) in the region from 1800 to 1000 cm⁻¹. Differential Scanning Calorimetry (DSC) analysis was conducted with a DSC 8000 (Perkin-Elmer Inc., Waltham, MA, USA) equipped with an intracooler system. The operation was performed on approximately 3 mg of each sample at a heating rate of 10 °C min⁻¹, from −70 °C to 200 °C. The DSC equipment was calibrated using indium as a standard, and the slope of the thermograms was corrected by subtracting similar scans of an empty pan. All tests were done in triplicate. For molecular weight analysis (number average molecular weight and weight average molecular weight, Mn and Mw, respectively), a multidetector gel permeation chromatography system consisting of a precolumn, two 300 mm × 0.8 mm M columns (PSS, Mainz, Germany), an isocratic pump 2080, an automatic injector AS 2050 (both Jasco, Tokyo, Japan), a RI detector Shodex RI-101 (Showa Denko, München, Germany), and a dual detector T60A (Viscotek Corporation, Houston, TX, USA), was used. Briefly, chloroform was used as an eluent with a flow rate of 1 mL/min at 35 °C and 0.2% toluene as the internal standard. Polystyrene samples were used for universal calibration. All samples were prepared at a concentration of 2 mg/mL.