Noticeably enhanced microwave absorption performance via constructing molecular-level interpenetrating carbon network heterostructure

Microwave absorption materials (MAMs), which can simultaneously show high reflection loss (RL) and broad effective absorbance band (EAB) at a thinner matching thickness, were meaningful to the settlement of current electromagnetic wave pollution. Herein, all-polymer derived carbon foam with unique molecular-level interpenetrating carbon network (ICN) heterojunction interface was constructed. The heterostructure was fabricated through carbonizing the molecular-level miscible interpenetrating polymer networks (IPN) of polyimide foam (PIF) and bismaleimide (BMI), while target heterojunction was proved through several characterizations. Benefitting from stronger polarization loss gene derived from countlessly molecular-level heterojunction interface of ICN, higher RL value could be realized at a thinner matching thickness. As a result, when only orthogonal polymerizing 5 wt% BMI with PIF, maximum RL value of corresponding carbon foam (CPIF-CBMI-5%) could achieve -72.8dB at the matching thickness of only 2.05 mm. In addition, the matching thicknesses of CPIF-CBMI-5% that covered the whole X band and Ku band were significantly decreased by 25% (3.75 mm to 2.8 mm) and 21% (2.6 mm to 2.05 mm) respectively, which was also superior to most foam materials that decorated by traditional loading or doping. Moreover, maximum EAB of CPIF-CBMI-5% could also achieved 6.2 GHz at 2.05 mm and its density was as low as 0.026 g/cm(3). (C) 2021 Elsevier Ltd. All rights reserved.