Poly(lactide)/poly(butylene adipate-co-terephthalate)/carbon nanotubes composites with robust mechanical properties, fatigue-resistance and dielectric properties.

A styrene-glycidylmethacrylate-1-allyl-3-vinylimidazole epoxy functionalized ionomer (EFI) was synthesized, and the EFI and carbon nanotubes (CNTs) were co-introduced into poly(lactide)/poly(butylene-adipate-co-terephtalate) (PLA/PBAT) blends to fabricate high performance composites with excellent mechanical properties, fatigue-resistance and dielectric properties. It is revealed that EFI can improve the interaction force between PLA and PBAT by inducing the interfacial crosslink reaction, thereby improving the melt strength of the samples. EFI can also refine the dispersion of CNT in the composites owing to the non-covalent force between EFI and CNT, promote the formation of filler network inside composites, which is demonstrated by DMA and rheological test results. The CNT can be anchored at the interface between PLA and PBAT owing to the interaction between EFI and CNT, and the synergistic effect of CNT and EFI on the interfacial structure and phase structure can significantly enhance the mechanical properties of the materials. When the CNT content is 3 wt%, the composite has a tensile strength of 30.4 MPa and an elongation at break of 279.3 %, which are 30 % and 48 % higher than that of PLA/PBAT blend, and it also exhibits excellent dielectric properties with a dielectric constant of 25.2 and a dielectric loss of 11.6. Moreover, the composites also have excellent fatigue resistance owing to the refined interfacial structure and compact CNT network.