As we know, fully exfoliated GO nanosheets can be
dispersed in a polar organic solventN,N-dimethylformamide
(NMF) without any assistance of chemical treatment [42]. In
our system, PLA/PU/GO composite films were prepared by
a simple liquid-phase mixing followed by casting.Figure 2
shows the SEMimages of the fracture surfaces of the PLA/PU
and PLA/PU/GO (5%) films