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Excellent electromagnetic wave loss and impedance matching are typical characteristics of superior‐performance electromagnetic wave (EMW) absorption materials. Changing the component ratios and multidimensional combinations of various absorbing materials is one of the best methods to improve absorption performance. This work used a convenient physical mixing approach to combine three wave‐absorbing materials with various dimensions to successfully prepare Graphene/carbon nanotubes/Fe3O4 (G/C/Fe3O4)/paraffin composites. One‐dimensional (1D) tube carbon nanotubes (CNTs) pierced two‐dimensional (2D) sheet graphene to form a strong three‐dimensional (3D) conductive network, enhancing interfacial polarization without introducing zero‐dimensional (0D) magnetic Nano‐Fe3O4. Nevertheless, because of their significant dielectric characteristics, the graphene/carbon nanotube (G/C) paraffin composites displayed low impedance matching and electromagnetic wave absorption properties. At a mass ratio of 1:1, the G/C/paraffin composites achieved an ideal reflection loss (RL) of −11.99 db and an impedance matching value of 0.59. Adding Fe3O4 improved the impedance matching and electromagnetic wave loss performance and promoted the formation of a non‐homogeneous interface, improving interfacial polarization and reflection. The G/C/Fe3O4/paraffin composite, with a mass ratio of 1:1:6 and a filler ratio of 20%, achieved an optimum reflection loss of −37.2 dB and an effective absorption bandwidth of 4.16 GHz. This work optimized and improved the performance of EMW materials practically and rapidly, providing a research method for the widespread application of superior‐performance electromagnetic wave absorption materials. Highlights: The EMW absorption materials with various architectures.1D CNTs pierced 2D sheet graphene to form a strong 3D conductive network.Adding Fe3O4 promoted the formation of a non‐homogeneous interface.Electromagnetic synergies and different structural combinationsIt achieved excellent impedance matching and electromagnetic loss performance. [ABSTRACT FROM AUTHOR]

Noise pollution is one of the serious environmental pollutions. In recent years, the preparation of sound absorption composites using natural fibers as reinforcement material has attracted much attention. Sugarcane bagasse is a by-product of sugarcane. In order to improve the utilization rate of sugarcane bagasse, enrich and expand the application field of its renewable resources, sugarcane bagasse as a reinforcement material, and polycaprolactone as a matrix material are used to prepare sugarcane bagasse/polycaprolactone sound absorption composites by hot press molding technology to analyze the sound absorption performance. The sound absorption mechanism of the sugarcane bagasse sound absorption composites is revealed. First, the structural characteristics of sugarcane bagasse were characterized, and the relationship between its structure and sound absorption performance was analyzed. Second, the effects of sugarcane bagasse length, mass fraction, hot pressing pressure, hot pressing time, and hot pressing temperature on the sound absorption performance were investigated by one-factor analysis. The results show that when the length of sugarcane bagasse was 1.0 mm, the mass fraction was 35%, the hot pressing pressure was 12 MPa, the hot pressing time was 20 min, and the hot pressing temperature was 130°C, the average sound absorption coefficient was 0.38, the noise reduction coefficient was 0.31, and the maximal sound absorption coefficient was 0.80. This study provides an experimental and theoretical basis for the research and development of sound absorption composites made of sugarcane bagasse, and provides a new solution for the recycling of sugarcane bagasse. [ABSTRACT FROM AUTHOR]

In order to solve the problems of honeycomb sandwich structure electromagnetic wave absorbing composites with easy delamination, low strength, and a narrow absorption frequency band, a double-layer honeycomb 3D woven electromagnetic wave absorbing composite was designed and prepared. CST electromagnetic simulations and mechanical finite element simulations were combined with experimental analysis, respectively. The electromagnetic wave absorption properties and bending properties of the double-layer honeycomb 3D woven electromagnetic wave absorbing composite were revealed, and the electromagnetic wave absorption mechanism was elucidated. The results show that the lowest peak of reflection loss obtained from both simulation and experiment of electromagnetic wave absorption property occurs in the X-band with the values of 10.78 GHz and 9.28 GHz, respectively. The lowest reflection loss is −24.35 dB and −23.5 dB, respectively. The simulation results were in good agreement with the experimental results. The maximum loads obtained from simulation and experiment for the bending property were 2696.28 N and 2271.07 N, respectively. There is no obvious delamination damage to the yarn, and the material has good resistance to delamination. The structural-functional integration of load-bearing and electromagnetic wave absorption in double-layer honeycomb 3D woven electromagnetic wave absorbing composite will have great development potential in civil and military fields. [ABSTRACT FROM AUTHOR]