Two-Steps Method to Prepare Multilayer Sandwich Structure Carbon Fiber Composite with Thermal and Electrical Anisotropy and Electromagnetic Interference Shielding

Abstract

Carbon fiber (CF) composites performance enhancement is a research hotspot at present. In this work, first, a sandwich structure composite, CF@(carbon nanotube/Fe3O4)/epoxy (CF@(CNT/Fe3O4)/EP), is prepared by the free arc dispersion-CFs surface spraying-rolling process method, herein, CFs in the middle layer and (CNT/Fe3O4)/EP as top and substrate layer. Then, CF@(CNT/Fe3O4)/EP (on both sides) and CFs (in the middle) are overlapped by structure design, forming a multilayer CF@(CNT/Fe3O4)/EP-CFs composite with a CFs core sheath. A small amount of CNT/Fe3O4 is consumed, (CNT/Fe3O4)/EP and CFs core sheath realize thermal and electrical anisotropy and directional enhancement, and multilayer sandwich structure makes the electromagnetic interference (EMI) shielding performance better strengthened by multiple absorption–reflection/penetration–reabsorption. From CF-0 to CF-8, CNT/Fe3O4 content only increases by 0.045 wt%, axial thermal conductivity (λ‖) increases from 0.59 W/(m·K) to 1.1 W/(m·K), growth rate is 86%, radial thermal conductivity (λ⊥) only increases by 0.05 W/(m·K), the maximum λ‖/λ⊥ is 2.9, axial electrical conductivity (σ‖) increases from 6.2 S/cm to 7.7 S/cm, growth rate is 24%, radial electrical conductivity (σ⊥) only increases by 0.7 × 10−4 S/cm, the total EMI shielding effectiveness (EMI SET) increases by 196%, from 10.3 dB to 30.5 dB. This provides a new idea for enhancing CFs composite properties.

Review of Polymer-Based Composites for Electromagnetic Shielding Application

“…Polymer-based electromagnetic shielding composite materials with a layered structure offer significant design freedom, low cost, and strong microwave absorption ability. However, they encounter challenges in actual production [41,176,177]. The bonding of the layers in the layered structure material using physical methods can degrade the compatibility between the layers and may also lead to cracks forming during the bonding process.…”