The morphology of the samples was observed using a Nova NanoSEM 430 (FEI Company, USA).
The cryo-fracture surface was obtained after the blend was immersed in liquid nitrogen, while the impact fracture surface was obtained from the blend after impact testing.
In order to observe the crosslinked NR phase, the blends were subjected to a dichloromethane wash (ambient temperature) to remove the PLA phase at the surface, and then sufficiently dried.
Before morphological observation, the surface of samples was sputter coated with gold to prevent electrostatic
charging build-up during observation.