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