Preparation of BTO@GO@PU Composite Membrane and its Application in Microwave Absorption Field

2018 ◽  
Vol 923 ◽  
pp. 3-7
Author(s):  
Yong Jie Yan ◽  
Qing Qing Ni
Keyword(s):  
Graphene Oxide ◽  
Elastic Modulus ◽  
Microwave Absorption ◽  
Cross Section ◽  
Composite Membranes ◽  
Average Diameter ◽  
Absorption Property ◽  
Frequency Range ◽  
Mechanical Tensile ◽  
Absorption Field

Barium titanate/graphene oxide/polyurethane (BTO@GO@PU) composite membranes for microwave absorption were designed and fabricated by mechanical-blending of BTO and GO in PU medium, followed by mold formation. The cross section morphology of the BTO@GO@PU membrane indicated that the BTO nanoparticles with 450 nm average diameter are successfully incorporated into the PU matrix. Mechanical tensile measurement showed that, as the amount of BTO nanoparticles increased from 5 wt% to 20 wt%, the elastic modulus of the corresponding membrane increased up to 23.0 MPa elongation with the elongation above 450 %. Microwave absorption property of the BTO@GO@PU membranes were evaluated by measuring its reflection loss in the frequency range of 0.1-18 GHz. With the addition of BTO up to 20 wt%, the maximum absorptivity of the composite reached up to 51 %. This is attributed to the dielectric loss of BTO nanoparticles.

scholarly journals Reduced graphene oxide decorated with octahedral NiS2/NiS nanocrystals: facile synthesis and tunable high frequency attenuation

RSC Advances ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 5550-5556 ◽  
Author(s):  
Min Lu ◽  
Na Gao ◽  
Xiao-Juan Zhang ◽  
Guang-Sheng Wang
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Microwave Absorption ◽  
High Frequency ◽  
High Frequency Range ◽  
Frequency Range ◽  
Facile Synthesis ◽  
Reduced Graphene ◽  
Absorption Performance ◽  
Microwave Absorption Performance

Reduced graphene oxide (RGO) decorated with octahedral NiS2/NiS nanocrystals were fabricated and they possessed an excellent microwave absorption performance in the high frequency range.

scholarly journals Combined Effects of Color and Elastic Modulus on Antifouling Performance: A Study of Graphene Oxide/Silicone Rubber Composite Membranes

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2608 ◽  
Author(s):  
Huichao Jin ◽  
Wei Bing ◽  
Limei Tian ◽  
Peng Wang ◽  
Jie Zhao
Keyword(s):  
Graphene Oxide ◽  
Elastic Modulus ◽  
Silicone Rubber ◽  
Composite Membranes ◽  
Superior Performance ◽  
Economic Losses ◽  
Combined Effects ◽  
Practical Applications ◽  
Rubber Composite ◽  
Static Conditions

Biofouling is a significant maritime problem because the growth of fouling organisms on the hulls of ships leads to very high economic losses every year. Inspired by the soft skins of dolphins, we prepared graphene oxide/silicone rubber composite membranes in this study. These membranes have low surface free energies and adjustable elastic moduli, which are beneficial for preventing biofouling. Diatom attachment studies under static conditions revealed that color has no effect on antifouling behavior, whereas the studies under hydrodynamic conditions revealed that the combined effects of color and elastic modulus determine the antifouling performance. The experimental results are in accordance with the “harmonic motion effect” theory proposed by us, and we also provide a supplement to the theory in this paper. On the basis of the diatom attachment test results, the membrane with 0.36 wt % of graphene oxide showed excellent antifouling performance, and is promising in practical applications. The results confirmed that the graphene oxide and graphene have similar effect to enhance silicone rubber antifouling performance. This study provides important insight for the design of new antifouling coatings; specifically, it indicates that lighter colors and low Young’s moduli provide superior performance. In addition, this study provides a reference for the application of graphene oxide as fillers to enhance the composite antifouling performance.

EFFECT OF REACTION TIME ON MICROSTRUCTURE, DIELECTRIC PROPERTY AND MICROWAVE ABSORPTION PROPERTY OF Cu-DOPED SiC NANOPOWDER

NANO ◽  
2014 ◽  
Vol 09 (02) ◽  
pp. 1450022 ◽  
Author(s):  
XIAOLEI SU ◽  
YONGSHENG TAN ◽  
YAN JIA ◽  
KAILI ZHAO ◽  
JUNBO WANG ◽  
...  
Keyword(s):  
Particle Size ◽  
Reaction Time ◽  
Microwave Absorption ◽  
Nitrogen Atmosphere ◽  
Microwave Absorption Property ◽  
Spherical Particles ◽  
Narrow Particle Size Distribution ◽  
Absorption Property ◽  
Frequency Range ◽  
X Ray Diffraction

Cu -doped SiC nanopowders have been prepared via combustion synthesis of the silicon and carbon system in a 0.1 MPa nitrogen atmosphere under different reaction time, using copper as the dopant and PTFE as the chemical activator, respectively. X-ray diffraction, scanning electronic microscope and Raman spectra have been used to characterize the phase and morphology of prepared nanopowders. Results indicate that the lattice constant of prepared Cu -doped SiC nanopowder decreases with extending reaction time. The prepared nanopowders have fine spherical particles and narrow particle size distribution and the particle size increases with increasing reaction time. The electric permittivities of prepared Cu -doped SiC nanopowders in the frequency range of 8.2–12.4 GHz have been determined. The real part ε′, imaginary part ε′′ and dielectric loss tgδ of complex permittivity decrease with increasing reaction time. All prepared Cu -doped SiC nanopowder exhibits good microwave absorption property in the frequency range of 8.2–12.4 GHz.

scholarly journals Acoustic Pressure Pipette Aspiration Method Combined with Finite Element Analysis for Isotropic Materials

2019 ◽  
Vol 9 (18) ◽  
pp. 3875
Author(s):  
Mohammadali Maghzinajafabadi ◽  
Raphael Lamprecht ◽  
Marion Semmler and Alexander Sutor
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Elastic Modulus ◽  
Cross Section ◽  
Acoustic Pressure ◽  
Vocal Folds ◽  
Frequency Range ◽  
Compression Force ◽  
Element Analysis ◽  
Pipette Tip

A measurement setup combined with a numerical simulation by a linear finite element analysis is presented as a method to determine the elastic modulus of both artificial and real tissue as a function of frequency. At the end, the future goal is to develop and validate the method to measure the elastic modulus of in-vivo human vocal folds over the human phonation frequency range. In the present study, a miniaturized acoustic pressure pipette aspiration technique is developed to measure the material characteristics of an isotropic silicone specimen with similar characteristics as human vocal folds. In previous studies, friction and compression force effects of the pipette tip wall on the surface of the sample and the radius of the pipette were not investigated. Moreover, the large scale of the measurement setups made them impossible to use for clinical applications. Therefore, two different pipette sample cross-section boundary conditions and two different pipette radii were used. With the aim of ensuring reliable results, we tested our method with pipettes of two different radii on four silicone samples with different consistencies over a frequency range of 50–500 Hz. The simulation verified the measurement results in which the strong dependency of the elastic modulus on the excitation frequency, radius of the pipette, the pipette tip compression force and friction was revealed. By the simulation results, two different frequency dependent equations were developed for calculating elastic modulus of the silicone mixtures in the two cross-section boundary conditions. It was concluded that using a very small gap in between the pipette tip and the specimen can cancel the impact of the pipette tip force and friction which are the major cause of uncertainty. However, if a connection between the pipette and the surface is unpreventable, the contact force should be restricted to be absolutely zero.

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