Polylactide/lignin blends: Effects of processing conditions on structure and thermo-mechanical properties

The effect of processing temperature and time on polylactide/lignin blends was evaluated. Two blends, one commercial and one prepared mixing polylactide (PLA) with different lignin contents, were processed at 190 and 170 °C for different mixing times. The commercial blend was a blend of PLA with 5 mass% of soda lignin and 15.4 mass% of softwood while, for the laboratory-made PLA/lignin, the content of lignin varied from 10 to 25 mass%. Both the blends showed significant degradation of the mechanical properties when processed at 190 °C. The use of lower processing temperature (i.e., 170 °C) showed minor degradation on both the blends. The lignin content showed a marked effect on the degradation behavior of the blends for all the processing temperatures tested.