Nano-lithium ferrite/nanosilica-filled butadiene-acrylonitrile rubber for microwave absorption

Abstract

Recently, the development of flexible and lightweight microwave-absorbing materials has become a trendy topic. Hence, the principal aim of this work is to enhance the microwave-absorbing performance of butadiene-acrylonitrile rubber (NBR) by incorporating novel reinforcing nanofillers. Cost-effective nano-lithium ferrite/nanosilica is synthesized via the precipitation of two thin layers of lithium ferrite with thicknesses of 10 and 20 % on the surface of cheap nanosilica extracted from rice husk agro-waste. To achieve optimal microwave-absorbing performance, both LiFe 10 %/Si and LiFe 20 %/Si NPs were incorporated into the NBR matrix at various loadings (2, 4, 8, and 16 parts per hundred rubber (phr)). Several investigations were performed on the NBR nanocomposites to explore their morphology, curing behavior, mechanical, equilibrium swelling, magnetic properties, and microwave-absorbing behavior. The mechanical characteristics of NBR nanocomposites reveal that the inclusion of LiFe/Si NPs enhanced their modulus, tensile strength, and elongation at break while reducing their hardness. Moreover, the obtained findings clarify that the 16 phr (LiFe 20 %/Si) filled-NBR nanocomposite has superior microwave-absorbing performance with a maximum absorption bandwidth of 2.2 GHz. Overall results reveal that the novel lithium ferrite/silica nanoparticles could be an effective filler for enhancing the microwave absorption efficiency of NBR nanocomposites. Thus, this research suggests a novel viewpoint on the fabrication of flexible microwave-absorbing materials.