Thermal analysis began with TGA tests, which helped to optimise the processing procedures for the materials tested. These tests made it possible to estimate the filler content in the composites and to evaluate the thermal stability under a specific temperature regime. Figure shows the TGA curves for PLA-based materials (4a) and PCL-based materials (4b). From these curves, together with the DTG curves (Figure ), thermal stability parameters were derived, including the temperatures corresponding to 5 % and 10 % weight loss (T5% and T10%), the temperatures at the maximum of the first derivative TGA peak (TDTG) and the residual mass at 600 °C (R600°C).