Structure-induced variation of thermal conductivity in epoxy resin fibers

Zeng, Xiaoliang; Xiong, Yucheng; Fu, Qiang; Sun, Rong; Xu, Jianbin; Xu, Dahai; Wong, Ching‐Ping

doi:10.1039/c7nr03717a

Cited by 15 publications

(13 citation statements)

References 36 publications

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“…However, Zeng et al . recently reported that a thermal contact resistance accounted for 30% to 50% of the total resistance of an electrospun epoxy resin NF, which was assembled on a suspended microdevice without the aid of electron-beam-assisted metal deposition 23 . Therefore, cyclohexane, which is a non-polar solvent, was dropped on the NFs and the suspended microdevices to reduce the contact thermal resistances between the NFs and the substrates.…”

Section: Methodsmentioning

confidence: 99%

“…Successively, more than 20-fold enhancements of k values were reported for electrospun and rapidly stretched polyethylene NFs 19,20 . In addition to polyethylene NFs, the k values of Nylon-11, polystyrene, and epoxy resin NFs were also significantly higher than those of their bulk counterparts 21–23 . This dramatic k increase proposes a possibility that polymer nanofibers can be used for various thermal applications such as thermal interface and functional fabric materials.…”

Section: Introductionmentioning

confidence: 92%

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Thermal conductivity enhancement in electrospun poly(vinyl alcohol) and poly(vinyl alcohol)/cellulose nanocrystal composite nanofibers

Park

You

Shin

et al. 2019

Sci Rep

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The thermal conductivity enhancement of neat poly(vinyl alcohol) and poly(vinyl alcohol) (PVA)/cellulose nanocrystal (CNC) composite was attempted via electrospinning. The suspended microdevice technique was applied to measure the thermal conductivity of electrospun nanofibers (NFs). Neat PVA NFs and PVA/CNC NFs with a diameter of approximately 200 nm showed thermal conductivities of 1.23 and 0.74 W/m-K, respectively, at room temperature, which are higher than that of bulk PVA by factors of 6 and 3.5, respectively. Material characterization by Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis confirmed that the thermal conductivity of the PVA/CNC NFs was enhanced by the reinforcement of their backbone rigidity, while that of the neat PVA NFs was attributed to the increase in their crystallinity that occurred during the electrospinning.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 92%

Thermal conductivity enhancement in electrospun poly(vinyl alcohol) and poly(vinyl alcohol)/cellulose nanocrystal composite nanofibers

Park

You

Shin

et al. 2019

Sci Rep

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“…Zeng et al [27] measured the thermal conductivity of the epoxy resin fibers made by electrostatic spinning technology and they found the value can be as high as 0.8 Wm -1 K -1 . In their following work [28], they found the thermal conductivity of epoxy resin fibers increases on decreasing the fiber diameter.…”

Section: Introductionmentioning

confidence: 95%

High Thermal Conductivity of Bulk Epoxy Resin by Bottom-Up Parallel-Linking and Strain: A Molecular Dynamics Study

Yu²,

Bao

et al. 2018

J. Phys. Chem. C

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The ultra-low thermal conductivity (~0.3 Wm -1 K -1 ) of amorphous epoxy resins significantly limits their applications in electronics. Conventional top-down methods e.g. electrospinning usually result in aligned structure for linear polymers thus satisfactory enhancement on thermal conductivity, but they are deficient for epoxy resin polymerized by monomers and curing agent due to completely different cross-linked network structure.Here, we proposed a bottom-up strategy, namely parallel-linking method, to increase the intrinsic thermal conductivity of bulk epoxy resin. Through equilibrium molecular dynamics simulations, we reported on a high thermal conductivity value of parallel-linked epoxy resin (PLER) as 0.80 Wm -1 K -1 , more than twofold higher than that of amorphous structure. Furthermore, by applying uniaxial tensile strains along the intra-chain direction, a further enhancement in thermal conductivity was obtained, reaching 6.45 Wm -1 K -1 . Interestingly, we also observed that the inter-chain thermal conductivities decrease with increasing strain. The single chain of epoxy resin was also investigated and, surprisingly, its thermal conductivity was boosted by 30 times through tensile strain, as high as 33.8 Wm -1 K -1 . Our study may provide a new insight on the design and fabrication of epoxy resins with high thermal conductivity. # S.L. and X.Y. contributed equal to this work.

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“…Also, it is thought that the degree of crosslinking may be sufficient for gauche conformation, which is formed at a higher temperature, to persist throughout the whole temperature range of the k measurement. As for a diameter dependence of k , several studies reported that the thermal conductivity of an electrospun polymer NF increased with decreasing diameter of the NF due to the effect of molecular chain alignment via electrospinning [6,8,37]. A similar diameter dependence was also observed for the mechanical properties of electrospun polymer NFs [38,39,40,41].…”

Section: Resultsmentioning

confidence: 57%

“…The electrospinning method, which draws nanofibers with an electrostatic force, also enhances the thermal conductivity of nanofibers. There have been several recent studies that reported k enhancement in electrospun Nylon-11, PE, and epoxy nanofibers [6,7,8,9].…”

Section: Introductionmentioning

confidence: 99%

Crosslinking Effect on Thermal Conductivity of Electrospun Poly(acrylic acid) Nanofibers

Park

Lee

et al. 2019

Polymers

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The thermal conductivity (k) of poly(acrylic acid) (PAA) nanofibers, which were electrospun at various electrospinning voltages, was measured using suspended microdevices. While the thermal conductivities of the as-spun PAA nanofibers varied depending on the electrospinning voltages, the most pronounced 3.1-fold increase in thermal conductivity in comparison to that of bulk PAA was observed at the electrospinning voltage of 14 kV. On the other hand, a reduction in the thermal conductivity of the nanofibers was observed when the as-spun nanofibers were either thermally annealed at the glass transition temperature of PAA or thermally crosslinked. It is notable that the thermal conductivity of crosslinked PAA nanofibers was comparable to that of crosslinked bulk PAA. Polarized Raman spectroscopy and Fourier transform infrared spectroscopy verified that the k enhancement via electrospinning and the k reduction by the thermal treatments could be attributed to the conformational changes between gauche and trans states, which may be further related to the orientation of molecular chains. In contrast, hydrogen bonds did not contribute significantly to the k enhancement. Additionally, the suppression of k observed for the crosslinked PAA nanofibers might result from the shortening of single molecular chains via crosslinking.

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Structure-induced variation of thermal conductivity in epoxy resin fibers

Cited by 15 publications

References 36 publications

Thermal conductivity enhancement in electrospun poly(vinyl alcohol) and poly(vinyl alcohol)/cellulose nanocrystal composite nanofibers

Thermal conductivity enhancement in electrospun poly(vinyl alcohol) and poly(vinyl alcohol)/cellulose nanocrystal composite nanofibers

High Thermal Conductivity of Bulk Epoxy Resin by Bottom-Up Parallel-Linking and Strain: A Molecular Dynamics Study

Crosslinking Effect on Thermal Conductivity of Electrospun Poly(acrylic acid) Nanofibers

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