Conductive polymer composite materials and their utility in electromagnetic shielding applications

Abstract

Commercial electronic devices require shielding solutions that ensure electromagnetic compatibility (EMC) while accounting for effects of specific enclosure structural features such as seams, vents, and port dimensions. In practice, suitable EMC materials combine with the device operating characteristics to determine an overall shielding response. To optimally couple plastic design practices with EMC requirements, both polymer materials science and electrical engineering concepts, must be considered. Use of extrinsically conductive polymer (ECP) formulations for electronic applications has advantages in that they can be directly molded to a desired shape and serve to provide the necessary shielding while also meeting mechanical integrity requirements. Shielding and mechanical performance can be varied via filler loading or altered through wall thickness changes to satisfy demands associated with a particular device. Injection-moldable ECP polycarbonate-based formulations can attain average shielding effectiveness (SE) levels of 50-60 dB through 2 GHz at 2-mm thickness as measured using ASTM D 4935 procedures. These values vary with thickness, and SE improvements of 10-20 dB are observed when increasing from 1 to 2 mm. Additionally, resultant mechanical properties of shielding composites are strong functions of overall fiber content. These interrelated material and shielding characteristics, which form the basis for filled conductive polymer use within practical enclosure shielding designs, are described.

Epoxy resin/polyetherimide/carbon black conductive polymer composites with a double percolation structure by reaction-induced phase separation

“…CPCs have many advantages including adjustable conductivity, simple processing, low cost, and thus they have extensive and important applications in many fields such as sensors, 9 antistatic materials, 10 electromagnetic shielding materials, 11,12 temperature and current control materials 13 and energy materials 14 (solar energy materials, battery materials, capacitor materials). As a result, CPCs have become a world-wide focus in the research field of polymer science and technology.…”

Temperature dependence of the conductivity behavior of graphite nanoplatelet‐filled epoxy resin composites

“…These materials are widely used as microwave absorbing materials, electromagnetic shielding materials, and antistatic materials, to name a few applications. [1][2][3] In addition, CPCs, with the properties of temperature dependence of the conductivity, are regarded as promising materials for applications in self-regulating heaters, self-resetting, overcurrent protectors, and sensors. [4][5][6] A signification part of investigations in this field concern carbon black-filled polymer composites, [7][8][9][10] which exhibit positive temperature coefficient (PTC) and negative temperature coefficient (NTC) effects in a wide range at or greater than the percolation threshold.…”

Effect of surface treatment of graphene nanoplatelets for improvement of thermal and electrical properties of epoxy composites

“…These CPCs have attracted significant attention due to their unique combination of metallic conductivity and polymeric properties [1]. For these reasons and more, CPCs are widely used as high strength composites, ultrasound transducers, electromagnetic shielding, electrically conductive, and thermal conductive materials [2][3][4][5].…”