Ultralow-Threshold and Lightweight Biodegradable Porous PLA/MWCNT with Segregated Conductive Networks for High-Performance Thermal Insulation and Electromagnetic Interference Shielding Applications

Abstract

Lightweight, biodegradable, thermally insulating, and electrically conductive materials play a vital role in achieving the sustainable development of our society. The fabrication of such multifunctional materials is currently very challenging. Here, we report a general, facile, and eco-friendly way for the large-scale fabrication of ultralow-threshold and biodegradable porous polylactic acid (PLA)/multiwalled carbon nanotube (MWCNT) for high-performance thermal insulation and electromagnetic interference (EMI) shielding applications. Thanks to the unique structure of the microporous PLA matrix embedded by conductive 3D MWCNT networks, the lightweight porous PLA/MWCNT with a density of 0.045 g/cm possesses a percolation threshold of 0.00094 vol %, which, to our knowledge, is the minimum value reported so far. Furthermore, the material exhibits excellent thermal insulation performance with a thermal conductivity of 27.5 mW·m·K, which is much lower than the best value of common thermal insulation materials. Moreover, it also shows outstanding EMI shielding performance characterized by its high shielding effectiveness (SE) values and absorption-dominated shielding feature. More importantly, its specific EMI SE is as high as 1010 dB·cm·g, which is superior to those of other shielding materials reported so far. Thus, this novel multifunctional material and its general fabrication methodology provide a promising way to meet the growing demand for high-performance multifunctional materials in sustainable development.

A review of the interfacial characteristics of polymer nanocomposites containing carbon nanotubes

“…A possible way to address the above problems, through using a relatively low concentration of carbon nanotubes, incorporates the ller in polymer nanocomposite materials. [352][353][354] A concomitant high aspect ratio and a tunable electrical conductivity may enable the electrical percolation of polymer nanocomposite materials to be achieved at a very low concentration of carbon nanotubes, with a high efficiency of electromagnetic interference shielding being obtained. 355,356 Recently, the underlying mechanism responsible for the electromagnetic interference shielding by using carbon nanotube-polymer nanocomposite materials has been illustrated by the research group of Uttandaraman Sundararaj.…”

“…A general, facile, and eco-friendly way has been developed by the research group of Chul B. Park 354,375 for the large-scale production of carbon nanotubepolymer nanocomposite materials by using foaming technology for both high-performance thermal insulation and electromagnetic interference shielding applications.…”

Polymer Composites for Flexible Electromagnetic Shields

“…Role of percolation can be illustrated from an example, where DC conductivity σ (DC), thermal conductivity λ, and SE have been plotted as a function of filler (multiwall carbon nano‐tube or MWCNT) content in a ultralow‐threshold (0.00094 vol.%) and biodegradable porous PLA/MWCNT network, where PLA is polylactic acid. High‐performance thermal insulation (thermal conductivity = 27.5 mW · m −1 · K −1 ) and good EMI shielding (high specific EMI SE of 1010 dB · cm 3 · g −1 ) have been reported.…”

Improvement in EMI Shielding Properties of Silicone Rubber/POE Blends Containing ILs Modified with Carbon Black and MWCNTs

“…However, silicone rubber is electrically-insulating and transparent to electromagnetic radiation. As electronic information technology has developed and the use of electronic devices has become more widespread, electromagnetic interference (EMI), which interrupts the functionality of electronic devices and severely affects human organs, has become a serious problem [2][3][4]. Therefore, conductive rubber composites containing carbon materials, such as carbon blacks and multi-walled carbon nanotubes, have excellent electrical conductivities and flexibility and have been widely used as EMI shielding materials [5,6].…”