Fabrication And Microwave Absorption Properties Of CF/BMI Composites Eletromagnetic Modified With Nano Film

Today stealth technology has become a key high-tech in military field,and structural absorbing materials as a bearing and absorbing dual functional composite materials can be designed,reduce the vehicle quality and overcome the narrow absorption band,heavy weight,low bond strength with the shell of the traditional coating type absorbing material.This paper presents a new method of layered electromagnetic modified composite material.Nano absorbing agent,in thermoplastic polyaryletherketone resin?PEK-C?membrane as the carrier,was inserted into the carbonfiber / bismaleimide?CF/BMI?composite material layer,to study on the wave properties and mechanical properties of absorbing composites materials with nano absorbing film,and design and preparation of composite materials with stealth function/bearing structure.This paper prepared carbon coated iron?Fe@C?/PEK-C nano composite film and Fe₃O₄/PEK-C electrospun nanofibers membrane of carbonfiber / bismaleimide resin?CF/BMI?composite layer of electromagnetic functional modification,to study the layered electromagnetic modification of CF/BMI composite interlayer morphology,dynamic mechanical properties,the interlaminar shear strength?ILSS?,flexural strength,electromagnetic parameters and absorbing properties.Studies of CF/BMI composites modified by Fe@C/PEK-C nano absorbing films show that,the interlaminar shear strength of the commposites which was improved by interpenetrating structure forming in the interlaminar regions,increased firstly and then decreased with increasing Fe@C content loaded in PEK-C membranes.The investigation of the electromagnetic characteristics showed that both the dielectric loss and magnetic loss were enhanced with increasing Fe@C content.As the Fe@C content loaded in PEK-C membranes reached 20 wt.%,the novel RASs showed good microwave absorption properties with a minimum reflection loss?RL?value of-16.85 dB observed at 11.5 GHz at a thickness of 1.7 mm.The measured RL values obtained by free space technique system was in good agreement with the calculated RL values obtained by Matlab based upon the complex permeability and permittivity.Studies of CF/BMI composites modified by Fe₃O₄/PEK-C nanofiber membrane show that,because of the fiber membrane with interwoven network structure,the thermosetting resin infiltrating into the fiber membrane forming in the interlayer,playing a support role between layers of the material like the “wall”.With Fe₃O₄ content increasing in PEK-C membranes,the interlaminar shear strength and the flexural strength increased firstly and then decreased.When the Fe₃O₄ nanoparticles content in the films reached 20%,absorption maximum of modified CF/BMI composite reached-15 dB at 15.8GHz.