Silane functionalized cardanol/calcium carbonate epoxy‐reinforced polymer nanocomposites for sustainable microwave absorption applications

Abstract Microwave absorption properties of epoxy resin/cardanol (ER/C) and epoxy resin/silane functionalized cardanol (ER/SFC) nanocomposites with various percentages of calcium carbonate nanoplatelets (CCNPs) studied in the frequency range of 8–18 GHz. The CCNPs obtained from the mussel shell were reinforced into a cardanol‐toughened ER matrix to mimic the composite structure of the abalone shell. The phase separation between ER, SFC, and CCNPs encapsulated in a polymer matrix was analyzed with SEM, and the presence of a low level of Fe₃O₄ magnetic impurities of 0.007 emu/g present as shown and verified by XRD and VSM analyses. The nanocomposites with ER/SFC/CCNPs 3 wt.% demonstrate a high surface roughness of 3.467 nm and an enhanced hydrophobicity, as indicated by a high contact angle of 102°. The silanization‐induced localization of CCNPs facilitates a mutually conducive morphology for excellent viscoelastic and microwave absorption properties. The increase in damping factor ratio of approximately 0.85 augments the microwave absorption property and it observed that ER/SFC/CCNPs 3 wt.% nanocomposites show higher reflection loss (RL) of more than 99.9% with RL of −43 dB at 12 GHz. The research aims to fabricate cost‐effective and multifunctional nanocomposites for microwave absorption applications. Highlights Excellent hydrophobicity owing to the surface roughness of 3.467 nm. Maximum contact angle of 102.1° due to the reinforcement of CCNPs and SFC to the epoxy matrix. Efficient microwave attenuation due to the reflection loss of −43 dB. Excellent microwave absorption of 99.99% with a damping factor of 0.85. Higher storage modulus due to the strong inter‐penetrating network of the composite.