Ultralow percolation threshold biodegradable PLA/PBS/MWCNTs with segregated conductive networks for high‐performance electromagnetic interference shielding applications

Abstract

The formation of dense and complete conductive networks in the electromagnetic interference (EMI) shielding composite is the basis for its excellent EMI shielding performance. In this work, biodegradable poly (lactic acid)/poly (butylene succinate)/multi‐walled carbon nanotubes (PLA/PBS/MWCNTs) nanocomposites with segregated structures were successfully prepared via melt blending. Due to the successful preparation of segregated structures and the fact that MWCNTs were mainly dispersed in the PBS phase, an ultralow percolation value of 0.071 vol% was achieved in biodegradable PLA/PBS/MWCNTs nanocomposites. When the MWCNTs content is 0.499 vol%, the electrical conductivity of the PLA/PBS/MWCNTs nanocomposites with segregated structures is around 7.15 × 10−3 S/m, which is about 6 orders of magnitude higher than that of the PLA/PBS/MWCNTs nanocomposites with normal structures. When the MWCNTs content increased to 2.0 wt%, the average EMI shielding effectiveness (SE) of segregated structures remained stable at 27.56 dB, which can effectively block 99.82% of the microwave radiation. Furthermore, as suggested in the EMI shielding analysis, the EMI shielding of PLA/PBS/MWCNTs nanocomposites is mainly through absorption shielding, so there will be no secondary environmental pollution. This study provides a practical and universal method to prepare biodegradable conductive polymer composites with ultralow percolation threshold and excellent EMI SE.

Regenerable and Ultraflexible Sustainable Film Derived from Tree Gum Kondagogu for High-Performance Electromagnetic Interference Shielding

“…The specific SE value (SSE/ t ) is deployed to equate EMI shielding performance, and it links with three primary parameters (EMI SE, thickness, and density). A recently reported bio-based, biodegradable polymer composite of poly­(lactic acid) (PLA)/poly­(butylene succinate)/MWCNTs has a total EMI SE of 27.56 dB . Furthermore, it has been observed that the total EMI SE of PLA/Graphene nanocomposites reached a maximum value of 15.5 dB in X-bands at 15 wt % graphene loading .…”

“…A recently reported bio-based, biodegradable polymer composite of poly(lactic acid) (PLA)/poly(butylene succinate)/MWCNTs has a total EMI SE of 27.56 dB. 43 Furthermore, it has been observed that the total EMI SE of PLA/Graphene nanocomposites reached a maximum value of 15.5 dB in X-bands at 15 wt % graphene loading. 44 In another study, carbon nanofiber mat shielding effectiveness of 52.2 dB has been reported.…”

Forefront Research of Foaming Strategies on Biodegradable Polymers and Their Composites by Thermal or Melt-Based Processing Technologies: Advances and Perspectives

“…Cells were nucleated around the interface between PLA and PBS, resulting in an open-cell morphology compared to the closed-cell morphology of neat PLA foam. Tian et al [445] prepared biodegradable PLA/PBS/multi-walled carbon nanotube (MWCNT) nanocomposites with segregated structures by melt blending. They reported that the MWCNTs were mainly dispersed in the PBS phase, which resulted in an ultralow percolation value of 0.071 vol%.…”

Polymer blend templated hierarchical porous composites with segregated structure and enhanced electromagnetic interference shielding performance

“…Another non‐negligible point is the impedance mismatch between conductive filler and polymer matrix, which is also a key factor in achieving high shielding performance 40,41 . Recently, constructing multiple interfaces have been well demonstrated to improve EMI SE of CPCs, such as porous/foam structure, 6,42,43 layered structure, 44,45 multiple phase blends, 46–49 segregated structure 50,51 . It is the multiple interfaces that increase the reflection/scattering and interfacial conduction of electromagnetic waves, resulting in an improved EMI SE.…”

“…40,41 Recently, constructing multiple interfaces have been well demonstrated to improve EMI SE of CPCs, such as porous/foam structure, 6,42,43 layered structure, 44,45 multiple phase blends, [46][47][48][49] segregated structure. 50,51 It is the multiple interfaces that increase the reflection/scattering and interfacial conduction of electromagnetic waves, resulting in an improved EMI SE. Therefore, a tailored conductive network and matrix structure in CPCs is of great necessity in obtaining desirable EMI SE.…”