2.4. Differential Scanning Calorimetry (DSC) and Degree of Crystallinity

DSC studies were carried out using a DSC Discovery apparatus (TA Instruments, New Castle, DE, USA). The measurements were conducted in three cycles (heat–cool–heat), in a temperature range from −90 to 320 °C with a heating and cooling rate of 10 °C/min for PCL, and in a temperature range from −30 to 300 °C with a heating and cooling rate of 10°C/min for PLA. Results discussed in work were taken from second heating curves (first heating and cooling were performed to reduce the thermal history of tested samples). Three samples of each polymer were analyzed. Obtained DSC curves were used to analyze the glass transition temperature (T_g), crystallization temperature (T_c), cold crystallization enthalpy (ΔH_c), melting temperature I, and fusion enthalpy (ΔH_m). The degree of crystallinity (X_c) for the samples was determined according to the following Equation (4):

where ΔH_m¹⁰⁰ is fusion enthalpy of 100% crystalline PLA/PCL (93.7 J/g for PLA [66] and 135.3 J/g for PCL [67]).