Improvement in toughness of polylactide/poly(butylene adipate-co-terephthalate) blend by adding nitrile rubber

This paper describes the preparation and characterization of the effects of polylactide (PLA), poly(butylene adipate-co-terephthalate) (PBAT) and nitrile rubber (NBR) blends. First, a commercial PLA/PBAT blend was characterized by using the Fourier transform infrared spectroscopy and thermal gravimetric analysis. The results show that commercial blend is composed by ~70 wt% of PLA and 30 wt% of PBAT. The PLA/PBAT/NBR blends and also a reference of PLA/PBAT blend were processed by extrusion and compression molding. Then, all compositions were evaluated by their toughness and the thermal behaviors. Special attention was given to the morphology evaluated by scanning electron microscope. The result showed PLA presented in all compositions suffered thermo-mechanical degradation. However, a significant improvement in the toughness was observed for all compositions produced with NBR. That fact was proved by both Izod impact test and the morphology analyses. Additionally, the morphology comparison among the blends also shows that the addition of NBR helps to reduce the size of the PBAT domains in the PLA matrix.