Effect of carbon nanotubes on the interface evolution and dielectric properties of polylactic acid/ethylene–vinyl acetate copolymer nanocomposites

The composites of polylactic acid/glycidyl methacrylate of grafted ethylene–vinyl acetate copolymer/ethylene–vinyl acetate copolymer/carbon nanotubes (PLA/EVA- g -GMA/EVA/CNTs) were prepared by melt-blended. The effects of CNTs on the interfacial morphological evolution and dielectric properties of the PLA/EVA- g -GMA/EVA composites were investigated. The introduction of CNTs reduced the reaction efficiency of epoxy groups in EVA- g -GMA with terminal hydroxyl and terminal carboxyl groups of the PLA, which resulted in a decrease in the mechanical properties of the materials slightly. In addition, the introduction of CNTs as a solid filler which limited the movement of PLA segment thus caused the PLA crystal to grow slowly, which reduced the crystallization ability of the PLA, but improved the thermal stability of the composite material. Most importantly, the introduction of CNTs obviously improved the dielectric properties of the composites. Only 1% CNTs need to be added, and the dielectric constant of composites was increased from 5.81 to 11.08; at the same time, the tensile strength and elongation at break can reach 42.7 MPa and 70.5%, respectively. The material has both electrical properties and good balance of stiffness and toughness. This work offers an innovative methodology for facilely and massively creating high-performance multi-component PLA composites which can expand the application of PLA-based biodegradable materials in micron storage capacitors, integrated circuits, and other electronic fields. Graphical abstract EVA- g -GMA regulates the interface of PLA/EVA/CNTs nanocomposites and endows nanocomposites with excellent mechanical and dielectric properties.