The objective of this study is to prepare a bio-based and lightweight electromagnetic interference (EMI) shielding material in the range of 8-12 GHz. Organic castor oil-based polyurethane (PU) foam was synthesized by the mechanical stirrer mixing process, whereas absorption and hydrothermal reduction processes have been used to reinforce the multi-walled carbon nanotube (MWCNT), cupric oxide (CuO) and bamboo charcoal (BC) nanoparticles in the organic PU foam. The EMI shielding properties of the PU foam composite were tested using a vector analyzer test setup. Identification of the structural property of the nanocomposite was analyzed using field-emission scanning electron microscopy images. The density of the organic PU foam composite reinforced with nanoparticles was calculated with the help of mass and volume. Response surface methodology has been used to systematically design and analyze the experiments of EMI shielding effectiveness (EMI SE) and the physical properties of the reinforced foam. Using the EMI SE experimental results, mathematical models were developed to forecast the results and validate them with error estimation. An optimization study has revealed that 0.75 wt.% of MWCNT, 1.5 wt.% of CuO, and 1.5 wt.% of BC are the optimum parameters with 0.063750 g/cm 3 density for obtaining the maximum EMI SE.
Today, most commercial polyols used to make polyurethane (PU) foam are produced from petrochemicals. A renewable resource, castor oil (CO), was employed in this study to alleviate concerns about environmental contamination. This study intends to fabricate a bio-based and low-density EMI-defending material for communication, aerospace, electronics, and military appliances. The mechanical stirrer produces the flexible bio-based polyurethane foam and combines it with nanoparticles using absorption and hydrothermal reduction processes. The nanoparticles used in this research are graphite nanoplates (GNP), zirconium oxide (ZrO2), and bamboo charcoal (BC). Following fabrication, the samples underwent EMI testing using an EMI test setup with model number N5230A PNA-L. The EMI experimental results were compared with computational simulation using COMSOL Multiphysics 5.4 and an optimization tool using response surface methodology. A statistical design of the experimental approach is used to design and evaluate the experiments systematically. An experimental study reveals that a 0.3 weight percentage of GNP, a 0.3 weight percentage of ZrO2, and a 2.5 weight percentage of BC depict a maximum EMI SE of 28.03 dB in the 8–12 GHz frequency band.
The evolution of a sustainable green composite in various loadbearing structural applications tends to reduce pollution, which in turn enhances environmental sustainability. This work is an attempt to promote a sustainable green composite in buckling loadbearing structural applications. In order to use the green composite in various structural applications, the knowledge on its structural stability is a must. As the structural instability leads to the buckling of the composite structure when it is under an axial compressive load, the work on its buckling characteristics is important. In this work, the buckling characteristics of a woven flax/bio epoxy (WFBE) laminated composite plate are investigated experimentally and numerically when subjected to an axial compressive load. In order to accomplish the optimization study on the buckling characteristics of the composite plate among various structural criterions such as number of layers, the width of the plate and the ply orientation, the optimization tool “response surface methodology” (RSM) is used in this work. The validation of the developed finite element model in Analysis System (ANSYS) version 16 is carried out by comparing the critical buckling loads obtained from the experimental test and numerical simulation for three out of twenty samples. A comparison is then made between the numerical results obtained through ANSYS16 and the results generated using the regression equation. It is concluded that the buckling strength of the composite escalates with the number of layers, the change in width and the ply orientation. It is also noted that the weaving model of the fabric powers the buckling behavior of the composite. This work explores the feasibility of the use of the developed green composite in various buckling loadbearing structural applications. Due to the compromised buckling characteristics of the green composite with the synthetic composite, it has the capability of replacing many synthetic composites, which in turn enhances the sustainability of the environment.
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