Multifunctional starch/carbon nanotube composites with segregated structure: Electrical conductivity, electromagnetic interference shielding effectiveness, thermal conductivity, and electro-thermal conversion

Conductive polymer composites with segregated structure (s-CPCs) are widely used in the electronics industry. Achieving selective distribution of the conductive fillers in the polymer matrix is an effective way to construct s-CPCs. In this work, the starch was used as the matrix and the carbon nanotube (CNT) was used as the conductive fillers to fabricate multifunctional s-CPCs, via simple mechanical mixing and compression molding. During the processing, the starch underwent partial gelatinization, which was conducive to the fusion of the starch granules and the selective distribution of the CNT. Scanning electron microscope and atomic force microscope images showed that the CNT was attached to the surface of the starch granules to form a segregated structure. The starch/CNT composites exhibited a significant percolation, with a percolation threshold of 0.24 vol%. When the CNT content was 3.05 vol%, the starch/CNT composites exhibited a high electromagnetic interference (EMI) shielding effectiveness of 33.12 dB, which was commercially applicable in EMI shielding devices. The starch/CNT composites also possess good thermal management properties and can be used as thermal conductors and electro-thermal conversion devices. This work manifests the application prospect in the field of the electronics industry and broadens the application potential of starch.