Abstract
Thermal conductivity of polymer fibers in the axial direction has been extensively studied while thermal conductivity in the radial direction λ remains unknown. In this work, polymer fibers with different molecular arrangements (crystalline, liquid crystalline, and amorphous) were plastically deformed. λ was measured at engineering strains ϵ = 0.2-2.3 using time-domain thermoreflectance. λ decreases with increasing strains for polyethylene (PE) and poly(p-phenylene-2,6-benzobisoxazole) (PBO) fibers and is independent of strain for poly(methyl methacrylate) (PMMA) fibers. The extrapolated thermal conductivity at zero strain is λ0 ≈ 0.27 Wm-1 K-1 for crystalline PE, λ0 ≈ 0.29 Wm-1 K-1 for liquid crystalline PBO, and λ0 ≈ 0.18 Wm-1 K-1 for amorphous PMMA. λ of PE drops to λ ≈ 0.14 Wm-1 K-1 at ϵ = 1.9; λ of PBO drops to λ ≈ 0.12 Wm-1 K-1 at ϵ = 2.1. We attribute the decrease of λ with ϵ in crystalline and liquid crystalline fibers to structural disorder induced by plastic deformation. The combination of structural disorder and phonon focusing effects produces a thermal conductivity in deformed PE and PBO fibers that is lower than amorphous PMMA.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 646-650 |
| Number of pages | 5 |
| Journal | ACS Macro Letters |
| Volume | 5 |
| Issue number | 6 |
| DOIs | |
| State | Published - Jun 21 2016 |
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ASJC Scopus subject areas
- Organic Chemistry
- Polymers and Plastics
- Inorganic Chemistry
- Materials Chemistry
Cite this
Thermal Conductivity in the Radial Direction of Deformed Polymer Fibers. / Lu, Yanfu; Liu, Jun; Xie, Xu; Cahill, David G.
In: ACS Macro Letters, Vol. 5, No. 6, 21.06.2016, p. 646-650.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Thermal Conductivity in the Radial Direction of Deformed Polymer Fibers
AU - Lu, Yanfu
AU - Liu, Jun
AU - Xie, Xu
AU - Cahill, David G.
PY - 2016/6/21
Y1 - 2016/6/21
N2 - Thermal conductivity of polymer fibers in the axial direction has been extensively studied while thermal conductivity in the radial direction λ remains unknown. In this work, polymer fibers with different molecular arrangements (crystalline, liquid crystalline, and amorphous) were plastically deformed. λ was measured at engineering strains ϵ = 0.2-2.3 using time-domain thermoreflectance. λ decreases with increasing strains for polyethylene (PE) and poly(p-phenylene-2,6-benzobisoxazole) (PBO) fibers and is independent of strain for poly(methyl methacrylate) (PMMA) fibers. The extrapolated thermal conductivity at zero strain is λ0 ≈ 0.27 Wm-1 K-1 for crystalline PE, λ0 ≈ 0.29 Wm-1 K-1 for liquid crystalline PBO, and λ0 ≈ 0.18 Wm-1 K-1 for amorphous PMMA. λ of PE drops to λ ≈ 0.14 Wm-1 K-1 at ϵ = 1.9; λ of PBO drops to λ ≈ 0.12 Wm-1 K-1 at ϵ = 2.1. We attribute the decrease of λ with ϵ in crystalline and liquid crystalline fibers to structural disorder induced by plastic deformation. The combination of structural disorder and phonon focusing effects produces a thermal conductivity in deformed PE and PBO fibers that is lower than amorphous PMMA.
AB - Thermal conductivity of polymer fibers in the axial direction has been extensively studied while thermal conductivity in the radial direction λ remains unknown. In this work, polymer fibers with different molecular arrangements (crystalline, liquid crystalline, and amorphous) were plastically deformed. λ was measured at engineering strains ϵ = 0.2-2.3 using time-domain thermoreflectance. λ decreases with increasing strains for polyethylene (PE) and poly(p-phenylene-2,6-benzobisoxazole) (PBO) fibers and is independent of strain for poly(methyl methacrylate) (PMMA) fibers. The extrapolated thermal conductivity at zero strain is λ0 ≈ 0.27 Wm-1 K-1 for crystalline PE, λ0 ≈ 0.29 Wm-1 K-1 for liquid crystalline PBO, and λ0 ≈ 0.18 Wm-1 K-1 for amorphous PMMA. λ of PE drops to λ ≈ 0.14 Wm-1 K-1 at ϵ = 1.9; λ of PBO drops to λ ≈ 0.12 Wm-1 K-1 at ϵ = 2.1. We attribute the decrease of λ with ϵ in crystalline and liquid crystalline fibers to structural disorder induced by plastic deformation. The combination of structural disorder and phonon focusing effects produces a thermal conductivity in deformed PE and PBO fibers that is lower than amorphous PMMA.
UR - http://www.scopus.com/inward/record.url?scp=84975504165&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84975504165&partnerID=8YFLogxK
U2 - 10.1021/acsmacrolett.6b00048
DO - 10.1021/acsmacrolett.6b00048
M3 - Article
AN - SCOPUS:84975504165
VL - 5
SP - 646
EP - 650
JO - ACS Macro Letters
JF - ACS Macro Letters
SN - 2161-1653
IS - 6
ER -