Stress induced carbon fiber orientation for enhanced thermal conductivity of epoxy composites

Li, Maohua; Ali, Zulfiqar; Wei, Xianzhe; Li, Linhong; Song, Gongsheng; Hou, Xiao; Do, Hainam; Greer, James C.; Pan, Zhongbin; Lin, Cheng‐Te; Jiang, Nan; Yu, Jinhong

doi:10.1016/j.compositesb.2020.108599

Cited by 105 publications

(44 citation statements)

References 59 publications

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“…Epoxy resins with a network structure obtained by the curing reaction of epoxy and amine compounds are an important class of thermosetting resins. They are used in a wide range of applications including adhesives, − coating agents, , and sealants − due to their good mechanical properties, corrosion resistance, and electronic insulation. One of the outstanding features of epoxy resins is the facile tunability of the network architecture by varying the cross-linking density.…”

Section: Introductionmentioning

confidence: 99%

Cross-Linking Effect on Segmental Dynamics of Well-Defined Epoxy Resins

et al. 2021

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Epoxy resins with a network structure, which are obtained by curing reactions of epoxy and amine compounds, are an important class of thermosetting resins. We here report the segmental dynamics of epoxy resins in which the three-dimensional network was well-defined and systematically varied. What we found by experiments in conjunction with atomistic molecular dynamics simulation was that when the cross-linking density in the epoxy resins increased, the glass transition temperature increased with an associated reduction in the spatial scale of the cooperative rearranging region and the increase in the dynamic heterogeneity. The knowledge here obtained should be useful for a better understanding of the physical properties of thermosetting polymers.

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Section: Introductionmentioning

confidence: 99%

Cross-Linking Effect on Segmental Dynamics of Well-Defined Epoxy Resins

et al. 2021

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“…According to previous work, the probability of the carbon distribution versus Φ is equal to the distribution probability in elementary area times the perimeter of the circle, so the resulting curve is directly proportional to sin( Φ ). 12 Distributions approaching the random distribution imply that there is no preference for the orientation of the CFs. The results showed that the orientation of the annealed sample was close to the grey curve, indicating the irregular orientation of the CFs.…”

Section: Resultsmentioning

confidence: 98%

“…11 In our previous work, a mechanical field is instead used to align the CFs, with a resulting thermal conductivity of 32 W m −1 K −1 . 12 Although the work replaced an energy-costly electrical field with a mechanical field, it could not achieve full advantage of the CFs because the dispersion of the orientation of the CFs could not be fully constrained to a single direction. Freeze casting is another crucial method of aligning fillers with the assistance provided by the formation of ice crystals to achieve high thermal conductivity in a specific direction.…”

Section: Introductionmentioning

confidence: 99%

Crystallization induced realignment of carbon fibers in a phase change material to achieve exceptional thermal transportation properties

Qin

et al. 2022

J. Mater. Chem. A

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“…Epoxy resins are an important class of thermosetting resins, which are generally obtained by curing reactions between epoxy and amine compounds. They consist of a three-dimensional network where the segmental mobility is often frozen in a glassy state at room temperature. , To date, epoxy resins have found use in a wide range of applications including adhesives, − coating agents, , and sealants , owing to their good mechanical properties, corrosion resistance, and electrical insulation. To further improve their functionalization, mechanical properties such as stiffness and fracture toughness need to be precisely controlled.…”

Section: Introductionmentioning

confidence: 99%

Effect of Cross-Linking Density on Horizontal and Vertical Shift Factors in Linear Viscoelastic Functions of Epoxy Resins

et al. 2021

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Epoxy resins are an important class of thermosetting resins, and their network structure, obtained by the curing reaction of epoxy and amine compounds, plays an important role in the material properties. We here revisited a time−temperature superposition (TTS) principle applied to the dynamic viscoelastic functions of epoxy resins, in which the network was well defined and systematically varied on the basis of the length of nalkyl diamine. The superimposition of isothermal curves in the frequency domain required not only a horizontal shift but also a vertical shift, regardless of the length of n-alkyl diamine. The temperature dependence of the horizontal shift factor, a T , could be well expressed by the Williams−Landel−Ferry equation. The fitting parameter, called C 2 , increased with decreasing alkyl chain length of the diamine, meaning that the thermal expansion of the free volume was suppressed due to greater cross-linking density. This was qualitatively confirmed by a full-atomistic molecular dynamics (MD) simulation. Meanwhile, the vertical shift factor, b T , increased with increasing temperature, and the extent was smaller with increasing crosslinking density. This can be explained in terms of the entropic contribution to the modulus in the temperature region above the glass transition temperature. The entropy change estimated using the isobaric molar heat capacity from the MD simulation strongly supported this hypothesis. The knowledge here obtained should be useful for a better design of thermosetting polymers as well as for the prediction of long-term durability.

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Stress induced carbon fiber orientation for enhanced thermal conductivity of epoxy composites

Cited by 105 publications

References 59 publications

Cross-Linking Effect on Segmental Dynamics of Well-Defined Epoxy Resins

Cross-Linking Effect on Segmental Dynamics of Well-Defined Epoxy Resins

Crystallization induced realignment of carbon fibers in a phase change material to achieve exceptional thermal transportation properties

Effect of Cross-Linking Density on Horizontal and Vertical Shift Factors in Linear Viscoelastic Functions of Epoxy Resins

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