| Microwave absorption materials generally refer to electromagnetic wave absorbing materials,which are materials that can absorb external electromagnetic waves through energy conversion.It plays an active role in preventing electromagnetic wave interference and electromagnetic wave pollution.However,the current research on microwave absorption materials mainly focuses on powder microwave absorption materials,and which are restricted in many application fields due to few researches on flexible and lightweight microwave absorption materials.In order to expand the application field of microwave absorption materials,this article useed textile technology and composite technology to optimized fiber components.Through fabric structure designed and composite technology,explored the design and manufacture of flexible and lightweight structural and coating types.And absorbing textile composite materials with cutting characteristics,and its microwave absorption performance has been explored.The main research content and results of the thesis are as follows:Firstly,using silk as a precursor to prepare nitrogen-containing biomass carbon,and to study the effects of different carbonization temperatures on the structure,dielectric properties and microwave absorption properties of the obtained biomass carbon.The results showed that the silk still maintained a fibrous morphology after high-temperature carbonization,and the surface presented a roughened form when the carbonization temperature was at 800 ?.As the carbonization temperature increased,in the range of 600-900 ?,the degree of graphitization of the material,dielectric constant and electrical loss of the materials augmented..When the carbonization temperature was 800 ?,the obtained biomass carbon(referred to as C-800)had higher electrical loss and impedance matching was significantly better than other samples.The minimum reflection loss()at a thickness of 2.33 mm was-31.56 d B(10.08 GHz),and the effective microwave absorption bandwidth(EAB)was 4.12 GHz(9.35-13.43 GHz).Secondly,in this paper,nylon-based fibers with a carbon content of 12 wt% and a trace amount of ferroferric oxide were used as warp and weft yarns.Through fabric design,a three-dimensional orthogonal fabric was woven in a modified loom.The influence of fabric density on the wave-absorbing performance of the three-dimensional orthogonal fabric was studied,and its flexibility was analyzed.The results showed that when the warp density was 100pieces/10 cm and the weft density was 250 pieces/10 cm,the prepared three-dimensional orthogonal fabric had good microwave absorption properties.When the fabric was a single layer,the Ku-band reached-34.5 d B,and the EAB was 3.81 GHz.However,the microwave absorption performance in the commonly used X-band was not significant.When the fabric was double-layered,when the incident angle of the electromagnetic wave was 0°,its effective bandwidth can cover the X-band,which has a good microwave absorption performance,thus providing reliable reference data for the research of structural microwave absorption fabrics.Finally,using the designed and woven three-dimensional orthogonal fabric as the skeleton,carbon particles were used as functional modifiers,and water-based polyurethane was used as the matrix.The dipping method was used to prepare flexible absorbing textile composite materials.It also analyzed and studied the structure,microwave absorption properties and softness of composite materials.The results showed that the nano-scale carbon black particles were embedded in the fiber and compounded on the fabric,and they were not easy to fall off.The composite materials prepared with a single-layer fabric as a skeleton,the addition of carbon black significantly improved the impedance matching characteristics of the material,and improved the material's absorbing performance.The single-layer fabric-reinforced composite material had better microwave absorption properties than double-layer fabrics,which met the requirement of light-weight microwave absorption materials.When the carbon black content in the immersion solution was 15 wt%,the effective microwave absorption bandwidth of the material can cover the entire X band.When the test angle was 0°,and the microwave absorption rate reached 99% in the 10.11-11.91 GHz band(RL<-20 d B);when the test angle was 30°,it reached-41.33 d B at 10.64 GHz,and the microwave absorption rate reached 99% at 10.11-11.14 GHz.It showed that the prepared composite material had obvious advantages in lightness,thinness and flexibility. |
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