Improving the actuation performance of magneto-polymer composites by silane functionalisation of carbonyl-iron particles

Charles, Andrew D.M.; Rider, Andrew N.; Brown, Suzanne; Wang, Chun H.

doi:10.1016/j.compositesb.2020.108091

Cited by 19 publications

(18 citation statements)

References 68 publications

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“…Another contributing factor to this reduction in permittivity at high loadings could be the formation of a conductive network by the CIP phase, with percolation observed to occur at around 13 vol % for this material system. 42 Above percolation, the conductive network could serve to shield underlying CNTs from the incident field, leading to an apparent reduction in permittivity. The frequency invariance of the drop, however, would suggest this to be a less dominant factor as the skin depth at these frequencies should allow the electromagnetic field to reach the underlying material.…”

Section: Resultsmentioning

confidence: 99%

“…The pullout of the CIP particulates from the surface can be seen in the inset of Figure 10a, which is typical for CIP particulates used in their as-received state, due to surface oxidation formation and thus poor matrix adhesion. 42 In contrast to the good CIP dispersion, the CNTs appear to agglomerate, with an example shown in Figure 10b. This agglomeration is a result of van der Waals attraction forces, with the implementation of high-shear mixing shown to be effective in breaking these agglomerates (e.g., through roll milling 50 ).…”

Section: Resultsmentioning

confidence: 99%

“…A degassing agent, BYK-A550 (BYK Worldwide, Germany), was added during manufacture to minimize porosity expected at high particulate loadings. 42 Layer 2 of the aDLS was produced from a quartz fiberreinforced polymer (QFRP), composed of Astroquartz III in a 8H satin weave style 4581 (JPS Composite Materials, USA), and the same epoxy as used in layer 1. The ground plane of the aDLS was fabricated from a biaxial 0/90°carbon preimpregnated with a high-temperature cure epoxy system, EP280 (GMS Composites, Australia).…”

Section: Methodsmentioning

confidence: 99%

“…In this analysis, σ m was neglected for all layers as previous work on a CIP-based MPC 42 suggested very low conductivities, on the order of 10 −5 S/m, even after electrical percolation. Furthermore, four-point probe measurements (see Section S2 of the Supporting Information) of the CNT/epoxy system indicated electrical percolation at around 3 vol %, below the concentrations considered in the aDLS design (see Section 4.2).…”

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confidence: 99%

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Actuated Dielectric-Lossy Screen for Dynamically Suppressing Electromagnetic Interference

Charles

Rider

Brown

et al. 2020

ACS Appl. Electron. Mater.

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Existing methods for electromagnetic interference suppression typically employ attaching absorbers to the external surface of a structure at a fixed distance. In this work, we present a dynamically tunable, electromagnetic interference suppression technique using a multifunctional nanocomposite that offers a wider bandwidth and exceptional absorption when compared to existing approaches. The nanocomposite, incorporating carbon nanotubes and carbonyl iron powder, provides multiple functions as a lossy dielectric screen for attenuating electromagnetic waves, supporting stress, and conducting heat to dynamically control the position and hence the resonant characteristics of the absorbing screen. The dielectric properties of the nanocomposite were optimized for a target operational frequency, enabling a large reduction in the total thickness when compared with conventional resistive screen absorbers. Tuning the resonance around the design frequency yielded a peak absorption of −40.9 dB and an effective −10 dB bandwidth of 7.4 GHz in the 2−18 GHz frequency range. The mechanical and electromagnetic properties of the nanocomposite were characterized and found to correlate well with numerical and analytical modeling. The multifunctional nanocomposite and complimentary tunable structure design provide opportunities for highly improved EMI suppression structures.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Actuated Dielectric-Lossy Screen for Dynamically Suppressing Electromagnetic Interference

Charles

Rider

Brown

et al. 2020

ACS Appl. Electron. Mater.

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“…Shape memory polymer (SMP) is one of the most popular soft matters and has the capabilities of recovering its highly pre-deformed shapes in response to external stimuli, such as heat, solvent, light, electric or magnetic fields [1][2][3][4][5][6]. Different from the conventional shape-change soft matters, the SMP can have a temporarily fixed shape and then regain its permanent shape due to its special thermodynamics.…”

Section: Introductionmentioning

confidence: 99%

Multi-modal commutative dynamics in semi-crystalline polymers undergoing multiple shape memory behavior

Wang

Gorbacheva

et al. 2021

Smart Mater. Struct.

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Semi-crystalline polymers offer great opportunities for design and tuning of multi-shape memory effect (multi-SME) through their programmable melting transitions. However, coexistence of amorphous and crystalline components as well as their multiple interfaces results in complex cooperative dynamics. In this study, we propose a one-dimensional multi-modal dynamic model to describe the commutative and cooperative dynamics in semi-crystalline shape memory polymers undergoing multi-SME. A three-phase model and Takayanagi principle are firstly applied to study the cooperative dynamics of amorphous/crystalline components and their interfaces. Phase transition theory and modified Avrami theory are used to model the cooperative dynamics of glass and melting transitions, respectively. Commutative dynamics and glass/melting transitions are further investigated to achieve on-demand multi-SME and shape recovery behaviors. Finally, effectiveness of the newly established model was demonstrated to predict triple-SMEs and quadruple-SMEs in semi-crystalline polymers reported in literature, and the theoretically obtained results show good agreements with the experimental ones.

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Analysis of the effects of interfacial parameters on the thermal conductivity properties of SiC/SMPU composites

Guan,

Bao,

Wei

et al. 2024

Polymer Composites

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Silicon carbide (SiC)/shape‐memory polyurethane (SMPU) soft robots possess programmable shapes and dual‐drive capabilities based on electrical and thermal methods. Enhancing the thermal conductivity (TC) of these composite materials effectively enhances the driving performance of the soft robots. In this study, we tune the interfacial thickness between SiC particles and the SMPU polymer matrix to regulate the TC of the composites. The optimized composite exhibits a 244% increase in the in‐plane TC and 153% increase in the out‐of‐plane TC. Furthermore, optimization significantly enhances the speed and efficiency of the soft robots. This study reveals that interfacial thickness is a key factor in regulating interfacial heat transfer, potentially introducing a new approach for reducing interfacial thermal resistance in composite materials. This study contributes to a deeper understanding of interfacial heat‐ transfer mechanisms and establishes a new theoretical framework for designing and fabricating advanced composite materials for soft robots.Highlights Interfacial heat‐ transfer mechanism was revealed. Interfacial thickness primarily controls interfacial heat transfer. The in‐plane and out‐of‐plane thermal conductivities of prepared composites were enhanced by 244% and 153%, respectively, by modifying the interfacial thickness. The multifunctional performance of the composites was improved due to microscale mechanisms.

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Improving the actuation performance of magneto-polymer composites by silane functionalisation of carbonyl-iron particles

Cited by 19 publications

References 68 publications

Actuated Dielectric-Lossy Screen for Dynamically Suppressing Electromagnetic Interference

Actuated Dielectric-Lossy Screen for Dynamically Suppressing Electromagnetic Interference

Multi-modal commutative dynamics in semi-crystalline polymers undergoing multiple shape memory behavior

Analysis of the effects of interfacial parameters on the thermal conductivity properties of SiC/SMPU composites

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