Preparation of High Mechanical Performance Nano-Fe3O4/Wood Fiber Binderless Composite Boards for Electromagnetic Absorption via a Facile and Green Method

Abstract

Fe3O4/wood fiber composites are prepared with a green mechanical method using only distilled water as a solvent without any chemical agents, and then a binderless composite board with high mechanical properties is obtained via a hot-press for electromagnetic (EM) absorption. The fibers are connected by hydrogen bonds after being mechanically pretreated, and Fe3O4 nanoparticles (NPs) are attached to the fiber surface through physical adsorption. The composite board is bonded by an adhesive, which is provided by the reaction of fiber composition under high temperature and pressure. The Nano-Fe3O4/Fiber (NFF) binderless composite board shows remarkable microwave absorption properties and high mechanical strength. The optional reflection loss (RL) of the as-prepared binderless composite board is −31.90 dB. The bending strength of the NFF binderless composite board is 36.36 MPa with the addition of 6% nano-Fe3O4, the modulus of elasticity (MOE) is 6842.16 MPa, and the internal bond (IB) strength is 0.81 MPa. These results demonstrate that magnetic nanoparticles are deposited in binderless composite board by hot pressing, which is the easiest way to produce high mechanical strength and EM absorbers.

Processing Lignocellulose-Based Composites into an Ultrastrong Structural Material

“…Apparently, the brushite/DNLC composites exhibit a better flexural strength and flexural modules than those of lignocellulose-based composites. The strength is 1.8–4.4 times higher than those of modified lignocellulosic materials without inorganic and organic filler (black squares). ,, The modules are 1.7–5.7 times higher than that of lignocellulosic materials with polymer and unenvironmentally friendly adhesive (half-filled red circle). − The integrated mechanical performance is far superior to those of the layered binary and ternary composites based on NLC (blue triangle). ,, − The cooperative work between brushite platelets and DNLC is accountable for increasing strength and modules. Inversely, covalent or ionic cross-linking is liable to increase strength but increase the limit of mutual movement of lignocellulose in deformation.…”

Green Synthesis of Composite Graphene Aerogels with Robust Magnetism for Effective Water Remediation

“…In Figure 5d, the peak at 712 eV could be assigned to Fe 2+ 2p 3/2 and Fe 3+ 2p 3/2 ; meanwhile, the peak at 725 eV may be attributed to the Fe 2+ 2p 1/2 and Fe 3+ 2p 1/2 [33], indicating compounds of various ferric oxides, and the proportion of amorphous Fe 3+ , With the presence of magnetic nanoparticles, the as-prepared M-CGAs exhibited an expected magnetic property. As shown in Figure 6a,b, the obtained M-CGAs exhibited an intriguing magnetic response behavior, and the corresponded saturation magnetization is as high as 55.7 emu•g −1 , which is superior to those of the reported works [23,32,[34][35][36]. Moreover, the remaining saturation magnetization and coercive forces were just 2.4 emu g −1 and 24 O e , respectively, which are the typical properties of a soft magnetic material.…”

Durable Photoetching Magnetic Biomass‐Based Hydrogel with High Performance

“…Compared with MCC hydrogel, the peaks of 30.5°, 35.7°, 43.4°, 57.5°, and 62.9° in the MCC@Fe 3 O 4 hydrogel, which derive from the (220), (311), (400), (511), and (440) crystal planes, indicting the presence of Fe 3 O 4 NPs. [ 18 ] Apart from the characteristic peaks of MCC and Fe 3 O 4 , a new and obvious peak (29.5°) is observed in the MCC@Fe 3 O 4 /lignin‐Ca 2+ hydrogel, which proves the characteristic plane of alkali lignin (Figure S1C, Supporting Information). Figure 1F illustrates the Fourier transform infrared (FT‐IR) spectra MCC, MCC@Fe 3 O 4 , and MCC@Fe 3 O 4 /lignin‐Ca 2+ hydrogel, in which the characteristic peaks (1155 and 1054 cm −1 ) are ascribed to the deformation vibration of C‐O‐C and C‐O, respectively (Figure S2, Supporting Information), demonstrating the successful crossing reaction between lignin and MCC by ECH.…”

“…[ 28 ] The MCC@Fe 3 O 4 /lignin‐Ca 2+ hydrogel was synthesized via a crosslinking reaction. [ 29 ] Typically, the hemicelluloses were removed from corn straw (1.25 g) via hydrothermal pretreatment (Table S1, Supporting Information), [ 18 ] followed by immersing into (3.5 g) NaOH solution (45 mL) at 80 °C for getting uniform and brown solution by removing residues. Then, the MCC@Fe 3 O 4 (3.5 g) and urea (6 g) were fully dissolved in the prepared lignin solution at −12 °C for 2 h. Later, 1.5 mL ECH and 0.25 g CaCl 2 were added into the dark brown MCC@Fe 3 O 4 /lignin dispersion with extensively stirring at 30 °C for 2 h ( Table 1 ).…”