Facile Preparation of Electromagnetic Interference Shielding Materials Enabled by Constructing Interconnected Network of Multi-walled Carbon Nanotubes in a Miscible Polymeric Blend

Qi-Yan Zhang,Zhao-Xia Guo,Han-Song Li,Bao-Hua Guo,Jian Yu

doi:10.1007/s10118-020-2370-5

Abstract

Electromagnetic interference (EMI) shielding materials are in great demand in electronic equipment and our surrounding environment to resist the increasing serious radiation pollution. Compared with their metal counterparts, conductive polymer composites (CPCs) have unique advantages of lightweight, corrosive resistance, low cost, and excellent processability, and are therefore an ideal choice for developing high-performance EMI shielding materials. However, CPCs based EMI shielding materials are limited to high filler loading, which caused poor mechanical properties and processability. Here, we demonstrate a facile and highly scalable approach to develop high-performance EMI shielding materials with low filler loading by using miscible poly(phenylene oxide)/polystyrene (PPO/PS) blend as the matrix. In contrast to PS/carbon nanotubes (CNTs) composites, PPO/PS/CNTs composites show much higher EMI shielding effectiveness caused by good dispersion of CNTs and highly interconnected conductive network. An excellent EMI shieling effectiveness of 23–25 dB is achieved for PPO/PS/10%CNTs composites with a thickness of only 375 µm, which is superior to most of reported polymer/CNTs composites prepared by melt-compounding. In addition, the results show that although absorption is the major shielding mechanism, the contribution of reflection is also important and closely related to the connectivity of conductive network, as well as the electrical conductivity of the CPCs.

Highlights

With the rapid development of modern electronic devices that get smarter and smaller by packing with large integrated circuits, electromagnetic interference (EMI) has become a new kind of pollution which has detrimental impacts on electronic equipment performance, surrounding environment as well as the human health.[1,2,3] it is emergent to develop highperformance Electromagnetic interference (EMI) shielding materials that can effectively shield radio frequency radiation.Reflection and absorption are two main mechanisms for EMI shielding.[4]
The results demonstrate that the EMI shielding effectiveness (SE) of poly(phenylene oxide)/polystyrene (PPO/PS)/carbon nanotubes (CNTs) composites is much higher than that of PS/ CNTs, which mainly results from increased contribution of reflection for the EMI radiation obtained by much better dispersion of CNTs and highly interconnected conductive network, even though absorption is the major shielding mechanism and reflection is the secondary shielding mechanism
The mechanism for the much better dispersion of CNTs in PPO/PS blend than that in PS matrix is attributed to the intermediate matrix viscosity of the PPO/PS blend matrix that had balanced effects on infiltration of polymer molecules and breakage of primary CNT agglomerates, which has been discussed in detail in our previous article.[17]

Summary

Introduction

With the rapid development of modern electronic devices that get smarter and smaller by packing with large integrated circuits, electromagnetic interference (EMI) has become a new kind of pollution which has detrimental impacts on electronic equipment performance, surrounding environment as well as the human health.[1,2,3] it is emergent to develop highperformance EMI shielding materials that can effectively shield radio frequency radiation.Reflection and absorption are two main mechanisms for EMI shielding.[4]. In contrast to PS/carbon nanotubes (CNTs) composites, PPO/PS/CNTs composites show much higher EMI shielding effectiveness caused by good dispersion of CNTs and highly interconnected conductive network.

Results

Conclusion