*2.2. Characterization Studies*

The morphology of the samples was characterized using an ultra-high field-emission scanning microscopy (FESEM) (SU8000, Hitachi Co., Tokyo, Japan). Cryogenically fractured surfaces from film specimens were coated with a ~5 nm Au/Pd layer to avoid charging during electron irradiation.

Wide-angle x-ray diffraction (WAXS) analysis were carried out using a Bruker D8 Advance diffractometer (Bruker AXS GmbH, Karlsruhe, Germany) and a Ni-filtered CuKα radiation source. Diffractograms were recorded at a 0.2 ◦/s scan speed and a resolution of 40 points/degree over the 2θ region of 5 to 35 ◦C. Diffractograms were also recorded at a scanning rate of approximately 7 ◦C/min to understand the dynamic crystallization and melting behavior of the samples. This was performed by initially holding them at a temperature of 190 ◦C for 5 min to erase any thermal history, and then cooling from 190 to 30 ◦C, followed by reheating them over the same temperature range and rate.

Thermogravimetric analysis (TGA) was performed using a TA Instruments Q50 thermobalance (Waters Cromatografía, S.A., Cerdanyola del Vallès, Spain) under nitrogen gas (flow rate = 60 mL/min) at 10 ◦C/min, over a temperature range of 100–800 ◦C.

Differential scanning calorimetry (DSC) was performed on a Perkin Elmer DSC7/7700 differential scanning calorimeter (Perkin-Elmer España SL, Madrid, Spain), calibrated with indium (*T*<sup>m</sup> = 156.6 ◦C, ∆*H*<sup>m</sup> = 28.45 kJ/kg) and zinc (*T*<sup>m</sup> = 419.47 ◦C, ∆*H*<sup>m</sup> = 108.37 kJ/kg) under the flow of nitrogen gas (25 mL/min). The samples were first heated to 220 ◦C and held at the same temperature for 5 min to erase the thermal history. Then, the crystallization of the samples was carried out by cooling from 220 to 40 ◦C, followed by heating cycles at 10 ◦C/min over the interval of temperatures between 40 and 220 ◦C. The crystallization/melting enthalpy of PLLA in the blend nanocomposites was determined by considering the weight fraction of PLLA in the nanocomposites.

Dynamic mechanical analysis (DMA) was performed on rectangular shaped samples using a Mettler DMA 861 device (Mettler-Toledo, Greifensee, Switzerland), at three frequencies of 0.1, 1, and 10 Hz in the tensile mode. An 8 N oscillating dynamic force using an amplitude of 17 µm at fixed frequency was adopted. The relaxation spectra were recorded over the temperature range −100 ◦C to 150 ◦C, at a heating rate of 3 ◦C/min.
