A facile method inspired by the cake making process is developed to fabricate reduced graphene oxide wrapped plant fiber sponges (PFS@rGO) through in situ coating and foaming. This method avoids the use of energy-intensive equipment for molding and drying, and hence has great potential in the production of large-sized rGO sponges. With a highly porous framework, good mechanical properties, efficient solar absorption, and low thermal conductivity, the as-fabricated hydrophilic and light-weight PFS@rGO readily floats on seawater and generates water vapor with a solar thermal conversion efficiency of 88.8% under 1 sun illumination.

A cake making strategy to prepare reduced graphene oxide wrapped plant fiber sponges for high-efficiency solar steam generation

Structure and performance control of plant fiber based foam material by fibrillation via refining treatment

This study investigates the application of mesoporous aluminosilicate material with hierarchical porosity to ultralow density wood fiber composite (ULD_WFC) for improving their mechanical properties. A 300 nm thickness Si–Al inorganic film was applied to the surface of the fibers. The mesoporous aluminosilicate material with many mesopores ranging from 2 to 20 nm was obtained. Their total pore volume and Brunauer–Emmett–Teller surface area were 0.193 cm3/g and 355.2 m2/g, respectively. Thermogravimetric analysis indicated that the thermostability of ULD_WFCs was affected by Si–Al compounds. But the residual weight of ULD_WFC with Si–Al compounds was 23.87% greater than composite without Si–Al compounds. The X-ray diffraction analysis indicated partial conversion of SiO2 to α-SiC. These conditions attributed to improving the mechanical properties of ULD_WFC. The modulus of elasticity, modulus of rupture, and internal bond strength of composite with Si–Al compounds increased by 547.4%, 240.0%, and 400.0%, r...

Mesoporous Aluminosilicate Material with Hierarchical Porosity for Ultralow Density Wood Fiber Composite (ULD_WFC)

Sensitive piezoresistive sensors using ink-modified plant fiber sponges

Si–Al compounds represent the substances having silicium (Si) and aluminum (Al) in the mixed aqueous solution of sodium silicate and aluminum silicate. Their chemical structure depends on Si–Al molar ratio. In this study, several Si–Al molar ratios were used to prepare different Si–Al compounds. These Si–Al compounds were added in the manufacturing process of ultra-low density fiberboards (ULDFs) to examine the effects of Si–Al molar ratio on the microstructure and the mechanical properties of ULDFs. Scanning electron microscope-energy dispersive spectroscopy, X-ray photoelectron spectrometer, infrared spectrometer, X-ray diffractometer and electronic universal testing machine were used to analyze the microstructure and mechanical properties of ULDFs. The results showed that the microstructure and bulk density of ULDFs were affected by Si–Al molar ratios. The mechanical properties of ULDFs were also significantly affected because of Si and Al components being uniformly distributed on the fibers’ surface and formation of Si–O–C bond. When Si–Al molar ratio was 2:1, the modulus of elasticity, modulus of rupture and internal bond strength of the ULDF was up to 20.78, 0.17, and 0.025 MPa, respectively.

Effect of Si–Al molar ratio on microstructure and mechanical properties of ultra-low density fiberboard

To improve mechanical properties of ultra-low density fiberboards (ULDFs), Si-Al compounds were mixed together with fibers during preparation of ULDFs, forming a thin film on the surface of the fibers via hydrogen bonding. This work mainly optimized two proposed methods in which the inorganic thin film was assembled on the surface of fibers, in terms of its effect on the mechanical properties of fibers. Microstructural characterization (such as micromorphology and elemental distribution, chemical bonding, and crystalline phase) of Si-Al compounds and ULDFs was done to evaluate the effects. The results revealed that an inorganic thin film (probably Al2O3-SiO2) covered the surface of the fibers. Compared with the control specimen, the modulus of elasticity, modulus of rupture, and internal bond strength of the specimen treated by the sol-gel process increased from 3.87 MPa to 13.19 MPa, 0.05 MPa to 0.16 MPa, and 0.010 MPa to 0.025 MPa, respectively. Based on its higher mechanical properties, a combined sol-gel method was judged to be better for enhancement of fibers than a separate deposition method.

Xiaozheng Liu

Papers

Modification of Ultra-Low Density Fiberboards by an Inorganic Film Formed by Si-Al Deposition and their Mechanical Properties