Epoxy/Glass Fiber Nanostructured p- and n-Type Thermoelectric Enabled Model Composite Interphases (original) (raw)
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An Approach toward the Realization of a Through-Thickness Glass Fiber/Epoxy Thermoelectric Generator
Materials
The present study demonstrates, for the first time, the ability of a 10-ply glass fiber-reinforced polymer composite laminate to operate as a structural through-thickness thermoelectric generator. For this purpose, inorganic tellurium nanowires were mixed with single-wall carbon nanotubes in a wet chemical approach, capable of resulting in a flexible p-type thermoelectric material with a power factor value of 58.88 μW/m·K2. This material was used to prepare an aqueous thermoelectric ink, which was then deposited onto a glass fiber substrate via a simple dip-coating process. The coated glass fiber ply was laminated as top lamina with uncoated glass fiber plies underneath to manufacture a thermoelectric composite capable of generating 54.22 nW power output at a through-thickness temperature difference οf 100 K. The mechanical properties of the proposed through-thickness thermoelectric laminate were tested and compared with those of the plain laminates. A minor reduction of approximate...
2016
Thermoelectricity is one of the energy harvesting techniques that converts waste heat into electrical energy by using a thermoelectric device, which has been confined to metal semiconducting materials. Although inorganic conductors and semiconductors can serve as efficient thermoelectric materials, they have such drawbacks as high processing costs, scarcity and toxicity. For these reasons, organic electronic materials have received attention, and research on thermoelectric systems has been conducted utilizing either conjugated polymers or carbon nanotubes (CNT)/polymer composites to date. We have focused on composites consisting of reinforcing woven fibers as thermoelectric materials, in conjunction with functionalization of woven fabric composites, which can serve as structural materials. We have characterized the thermal and electrical conductivities and Seebeck coefficients of fiber-reinforced composites, which are the constituents of thermoelectric efficiency factor, and confirmed the feasibility of using composites for thermoelectrics. In addition, numerical modeling approaches were developed to predict the thermal and electrical conductivities of composites and to optimize the figure of merit, an index for thermoelectric efficiency, with respect to such material variables as fiber volume fraction, aspect ratio and orientation. Two types of composites, namely, carbon nanotube (CNT)/glass fiber (GF)/epoxy multiscale hybrid composites and carbon fiber (CF)/epoxy composites, were fabricated, and their thermoelectric properties were evaluated as n-/p-type thermoelectric materials. Experimental results showed that the electrical resistivity of the CNT/GF/epoxy composites decreased as CNT concentration increased. Inplane samples showed higher electrical and thermal conductivities due to partial alignment of CNTs in the multiscale composites and continuity of CFs in CF/epoxy composites. In general, CF/epoxy composites showed better electrical and thermal conductivities than multiscale composites. In the Seebeck coefficient measurement test, the multiscale composites showed n-type thermoelectric behavior, whereas the CF/epoxy composites showed p-type behavior. When temperature gradients were applied to closed circuits comprised of multiscale composites and CF/epoxy composites as n-and ptype materials, respectively, an electric current was successfully generated. In the process of optimizing the figure of merit, modeling approaches combining the methods for nanocomposites and woven fabric composites were proposed to predict the thermal and electrical conductivities of composites. The Mori-Tanaka method, thermal-electrical analogy and rule-ofmixtures were adopted as the modeling tools, and we validated the modeling approaches through comparison with experimental data. Thermal-electrical analogy and modified Mori-Tanaka method predictions, which take into account fiber volume fraction, conductivity, aspect ratio, continuity and undulation, agreed well with experimental results. This study covers evaluation of the thermoelectric properties of composites in which reinforcing woven fibers are incorporated, including manufacturing and characterization of materials, structure of ii constituting materials, and validity of the composites as thermoelectric materials. We proposed and validated the modeling methodologies to predict the thermal and electrical conductivities of composites, taking into account the influences of constituents' structure, geometry and properties. The outcome of this study is expected to pave the way for a new method for energy harvesting where base materials are structural polymer composites that include reinforcing fibers and polymer matrix. Potential applications range from small devices like electronic and home appliances to large structures such as automotive, aerospace and civil structures. The uses of conductivity models developed can be expanded into other multifunctional applications, such as materials design for thermal management, electrostatic discharging, electromagnetic interference shielding, etc.
Materials advances, 2024
In this study, a multifunctional, hierarchically modified glass fiber-reinforced polymer composite laminate (GFRP) capable of harvesting thermoelectric energy is fabricated and demonstrated. The fibrous reinforcements were hierarchically patterned with alternate n-and p-type graphene nanotube (singlewalled carbon nanotube-SWCNT) aqueous dispersions, which were printed via ink dispensing processes. The optimal n-and p-type resin-impregnated printed films demonstrate high power factors of 82 and 96 mW m À1 K À2 , respectively, and excellent stability in air. The manufactured GFRP-based graphene thermoelectric generator (GTEG) has the capability to stably function up to 125 1C under ambient conditions (1 atm, RH: 50 AE 5% RH). Printed SWCNT-based thermoelectric (TE) modules were successfully designed and fabricated onto a glass fiber fabric substrate with remarkable properties of ntype and p-type TE thin films resulting in exceptionally high performance. The thermoelectrically functionalized GFRP exhibits excellent stability during operation with obtained TE values of an open circuit voltage V OC = 1.01 V, short circuit current I SC = 850 mA, internal resistance R TEG = 1188 Ohm, and a generated power output P max = 215 mW at DT = 100 1C with T C = 25 1C. The novelty of this work is that it demonstrates for the first time a multilayered hierarchically modified carbon-based energyharvesting structural composite, capable of powering electronic devices such as a LED light from the power it generates when exposed to a temperature difference, and the overall results are among the highest ever presented in the field of energy-harvesting structural composites and printed carbon-based thermoelectrics. Both experimental measurements and simulations validated the TE performance. In addition, GFRP-GTEG showed a bending strength of 310 MPa and a flexural modulus of 21.3 GPa under room temperature (RT) and normal conditions (25 1C), retaining to a significant extent its mechanical properties while simultaneously providing the energy-harvesting capability. The aforementioned functional composite may be easily scaled-up, delivering potential for industrial-scale manufacturing of high-performance TEG-enabled structural composites.
Applied Physics A
For a thermoelectric application, the thermal conductivity, electrical conductivity and figure of merit of epoxy resin-based composites incorporated with carbon nanotubes and TiO 2 are investigated in this paper. First, the composite is prepared with a solution blending method. Then, the structure, thermal and electrical conductivities are characterized with experimental methods. Finally, the thermal conductivity, electrical conductivity and figure of merit are discussed. Results turn out that with an increasing content of carbon nanotube fillers, there are different changing trends of thermal and electrical conductivities because of large difference between thermal and electrical contact resistances in the composite. With the increasing filler content, the electrical conductivity increases exponentially while thermal conductivity saturates to be a constant value. Due to the large ratio of electrical to thermal conductivities, the figure of merit with 8 wt% of fillers is more than 50 times larger than that with a low content of fillers. Our results confirm that the recently proposed concept of 'electron-percolation thermal-insulator' is a feasible way to enhance the figure of merit of a polymer composite.
ACS Nano, 2010
The thermoelectric properties of carbon nanotube (CNT)-filled polymer composites can be enhanced by modifying junctions between CNTs using poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS), yielding high electrical conductivities (up to ϳ40000 S/m) without significantly altering thermopower (or Seebeck coefficient). This is because PEDOT:PSS particles are decorated on the surface of CNTs, electrically connecting junctions between CNTs. On the other hand, thermal transport remains comparable to typical polymeric materials due to the dissimilar bonding and vibrational spectra between CNT and PEDOT:PSS.
Carbon, 2013
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Study of Thermal and Mechanical Properties of Fiber-Glass Multi-Wall Carbon Nanotube/Epoxy
Frontiers in Heat and Mass Transfer
This project aims at determining both numerical and experimental to some thermal properties and its thermal expansion coefficient, thermal conductivity and mechanical properties of reinforcement of fiber glass woven with matrix of multi wall carbon nanotube MWCNT / epoxy composite. First, this powder is known to have a very good thermal properties. So, the nanopartical combined with resin has poor thermal properties. Secondly, the development a complete solution for the manufacturing of multi wall carbon nanotube /epoxy composites different volume fraction from 1% to 10% with increment of 2% to compare the result of finite element method by using ANSYS program with experimental results to determine the mechanical and thermal properties for nanocomposite materials. The finite element by using ANSYS is good agreement with experimental data for different volume fraction. The thermal conductivity of the nanocomposite materials increases with increasing in the volume fraction concentration thermal expansion coefficient reduces with increasing in the volume fraction concentrations. The increment nano particle concentration effect on the mechanical properties is accomplished the best results.
Tuning Electrical and Thermal Properties in Epoxy/Glass Composites by Graphene-Based Interphase
Journal of Composites Science, 2017
Multiscale epoxy/glass composites were fabricated by using E-glass fibers (GF) coated with different types of graphene nanosheets deposited by electrophoretic deposition. Graphene oxide (GO) was first synthesized using modified Hummer's method and its subsequent ultrasonication in de-ionized water created a stable suspension of GO. GF were immersed in the water/GO suspension near a copper anode. The electrical potential applied between the electrodes caused GO to migrate towards the anode. Moreover, the GO coated yarns were exposed to hydrazine hydrate at 100 • C to obtain reduced graphene oxide (rGO) coated yarns. Both GO and rGO coated GF yarns were used to create unidirectional epoxy-based multiscale composites by hand lay-up. The presence of a conductive rGO coating on GF improved both the electrical and thermal conductivities of composites. Moreover, enhanced permittivity was obtained by rGO based epoxy/glass composites, thus giving the option of using such structures for electromagnetic interference shielding.