7 research outputs found
Multifunctional Stiff Carbon Foam Derived from Bread
The
creation of stiff yet multifunctional three-dimensional porous carbon
architecture at very low cost is still challenging. In this work,
lightweight and stiff carbon foam (CF) with adjustable pore structure
was prepared by using flour as the basic element via a simple fermentation
and carbonization process. The compressive strength of CF exhibits
a high value of 3.6 MPa whereas its density is 0.29 g/cm<sup>3</sup> (compressive modulus can be 121 MPa). The electromagnetic interference
(EMI) shielding effectiveness measurements (specific EMI shielding
effectiveness can be 78.18 dB·cm<sup>3</sup>·g<sup>–1</sup>) indicate that CF can be used as lightweight, effective shielding
material. Unlike ordinary foam structure materials, the low thermal
conductivity (lowest is 0.06 W/m·K) with high resistance to fire
makes CF a good candidate for commercial thermal insulation material.
These results demonstrate a promising method to fabricate an economical,
robust carbon material for applications in industry as well as topics
regarding environmental protection and improvement of energy efficiency
Stiff, Thermally Stable and Highly Anisotropic Wood-Derived Carbon Composite Monoliths for Electromagnetic Interference Shielding
Electromagnetic
interference (EMI) shielding materials for electronic
devices in aviation and aerospace not only need lightweight and high
shielding effectiveness, but also should withstand harsh environments.
Traditional EMI shielding materials often show heavy weight, poor
thermal stability, short lifetime, poor tolerance to chemicals, and
are hard-to-manufacture. Searching for high-efficiency EMI shielding
materials overcoming the above weaknesses is still a great challenge.
Herein, inspired by the unique structure of natural wood, lightweight
and highly anisotropic wood-derived carbon composite EMI shielding
materials have been prepared which possess not only high EMI shielding
performance and mechanical stable characteristics, but also possess
thermally stable properties, outperforming those metals, conductive
polymers, and their composites. The newly developed low-cost materials
are promising for specific applications in aerospace electronic devices,
especially regarding extreme temperatures
Superflexible Interconnected Graphene Network Nanocomposites for High-Performance Electromagnetic Interference Shielding
Graphene-enhanced polymer matrix
nanocomposites are attracting ever increasing attention in the electromagnetic
(EM) interference (EMI) shielding field because of their improved
electrical property. Normally, the graphene is introduced into the
matrix by chemical functionalization strategy. Unfortunately, the
electrical conductivity of the nanocomposite is weak because the graphene
nanosheets are not interconnected. As a result, the electromagnetic
interference shielding effectiveness of the nanocomposite is not as
excellent as expected. Interconnected graphene network shows very
good electrical conduction property, thus demonstrates excellent electromagnetic
interference shielding effectiveness. However, its brittleness greatly
limits its real application. Here, we propose to directly infiltrate
flexible polyÂ(dimethylsiloxane) (PDMS) into interconnected reduced
graphene network and form nanocomposite. The nanocomposite is superflexible,
light weight, enhanced mechanical and improved electrical conductive.
The nanocomposite is so superflexible that it could be tied as spring-like
sucker. Only 1.07 wt % graphene significantly increases the tensile
strengths by 64% as compared to neat PDMS. When the graphene weight
percent is 3.07 wt %, the nanocomposite has the more excellent electrical
conductivity up to 103 S/m, thus more outstanding EMI shielding effectiveness
of around 54 dB in the X-band are achieved, which means that 99.999%
EM has been shielded by this nanocomposite. Bluetooth communication
testing with and without our nanocomposite confirms that our flexible
nanocomposite has very excellent shielding effect. This flexible nanocomposite
is very promising in the application of wearable devices, as electromagnetic
interference shielding shelter