Effect of LTI content on impact fracture property of PLA/PCL/LTI polymer blends

The effect of LTI content on the impact fracture toughness of poly(lactic acid) (PLA)/poly(ε-caprolacton (PCA)/lysine triisocyanate (LTI) polymer blends is discussed. Fracture micromechanism was also studied by observing fracture surfaces using a scanning electron microscope (SEM). The fracture mechanism was then correlated with the macroscopic impact fracture toughness value. Fracture surfaces created by the impact fracture tests were also observed by SEM to understand the effect of LTI content on the fracture micromechanism. The weight-average molecular weight increases with increase of LTI content as a result of crosslinking reaction. The phase transformation due to LTI addition tends to strengthen the microstructure and reduce the size of the spherical PCL phases, resulting in increase of energy dissipation at crack initiation and thereby improvement of the impact fracture toughness.