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

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 degrees. 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 degrees 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. Microwave absorption of calcium carbonate-based epoxy nanocomposite by multiple internal reflections. image