Note: Thermal conductivity measurement of individual poly(ether ketone)/carbon nanotube fibers using a steady-state dc thermal bridge method

Abstract

Customized engineered fibers are currently being used extensively in the aerospace and automobile industries due to the ability to “design in” specific engineering characteristics. Understanding the thermal conductivity of these new fibers is critical for thermal management and design optimization. In the current investigation, a steady-state dc thermal bridge method (DCTBM) is developed to measure the thermal conductivity of individual poly(ether ketone) (PEK)/carbon nanotube (CNT) fibers. For non-conductive fibers, a thin platinum layer was deposited on the test articles to serve as the heater and temperature sensor. The effect of the platinum layer on the thermal conductivity is presented and discussed. DCTBM is first validated using gold and platinum wires (25 μm in diameter) over a temperature ranging from room temperature to 400 K with ±11% uncertainty, and then applied to PEK/CNT fibers with diverse CNT loadings. At a 28 wt. % CNT loading, the thermal conductivity of fibers at 390 K is over 27 Wm−1K−1, which is comparable to some engineering alloys.

Prediction of interfacial thermal resistance of carbon fiber in one dimensional fiber-reinforced composites using laser flash analysis

“…But the result is influenced by the contact thermal resistance to the hot wire and the uncertainty related to the geometry. Moon et al [6] used a steady-state DC thermal bridge method to predict the thermal conductivity of carbon nanotube fiber. However, the results are significantly influenced by the value of electrical heating and electrical-thermal sensing, and also influenced by the contact thermal resistance between the sample and heat sink.…”

“…Typically, the radial dimension of the small fibers ranges from 1 to 30 lm, but yet the heterogeneity effects are still evident, rendering the homogeneous assumption incorrect and affecting various property measurement. Nowadays, there is no universal method which can simultaneously test the thermal conductivity and interface contact resistance of carbon fiber [3][4][5][6][7].…”

A Steady-state Method for the Estimation of the Thermal Conductivity of a Wire

“…The methods based on the previously described device may be classified in two types: -Steady-state [2]: in this case the electrical current intensity in the wire is constant: = 0 and the steady state value ̅ of the mean temperature rise only depends on the wire thermal conductivity and on the external heat transfer coefficient ℎ. Thus, can be deduced from a the steady-state measurement only if ℎ is known.…”

Synthesis of glass fiber‐multiwall carbon nanotube hybrid structures for high‐performance conductive composites

“…Since first reported by Ijima in 1991 , carbon nanotubes (CNTs) have triggered worldwide interests in view of their outstanding mechanical properties as well as excellent electrical and thermal conductivity. The integration of these properties makes them promising candidates as fillers in the design of high‐performance composite systems for many applications, including antistatic devices, capacitors, electromagnetic shielding materials, or parts of automotive engineering . Based on the very high‐aspect ratio (length‐to‐diameter ratio, l/ d ∼1,000) of CNTs, the polymer/CNT composites usually show much lower electrical percolation threshold values compared to the polymer composites reinforced by conventional conductive fillers, such as carbon black.…”