Evaluation of PLA content in PLA/PBAT blends using TGA

Sheng Xianga,b, Lidong Fenga,b,*, Xinchao Biana,b, Gao Lia,b, Xuesi Chena,bPolymer Testing81(2020)106211

The thermogravimetric analysis (TGA) was used to evaluate the polylactide (PLA) content in PLA/poly(butylene adipate-co-terephthalate) (PLA/PBAT) blends. The TGA curves of PLA/PBAT blends containing magnesium oxide (MgO) can clearly show two-step weight loss profiles because PLA can be selectively depolymerized in PLA/PBAT blends under the catalysis of MgO, and thus the PLA content can be determined according to the TGA curve for the blends. The detection scope of this method is especially applicable to the PLA content in the range of 10–90 wt% in PLA/PBAT blends at a heating rate 10 �C⋅min􀀀1. The measurement reliability was evaluated by parallel experiments. When the PLA content was 20, 50 and 80 wt%, the standard deviation (STDEV) and the absolute error for the measurements were less than 2.0 wt% and �1.0 wt%, respectively, which indicated that the method is sufficiently reliable.