Significant Enhancement of Thermal Conductivity in Polymer Composite via Constructing Macroscopic Segregated Filler Networks

Abstract

The low efficiency of thermal conductive filler is an unresolved issue in the area of thermal conductive polymer composites. Although it is known that minimizing phonon or electron interfacial scattering is the key for achieving high thermal conductivity, the enhancement is generally limited by preparation methods that can yield the ideal morphology and interfaces. Herein, low temperature expandable graphite (LTEG) is added into a commercial impact modifier (Elvaloy4170), which is then coated onto poly(butylene terephthalate) (PBT) particles with various sizes at millimeter scale between their melting temperatures. Thus, macroscopic segregated filler networks with several considerations are constructed: high LTEG loading leads to a short distance between fillers and a robust filler network; continuous Elvaloy-LTEG phase leads to a continuous filler network; and good interaction among filler and matrix leads to good interfacial interaction. More importantly, the rather large size of PBT particles provides the filler networks with low specific interfacial area, which minimizes the interfacial scattering of phonons or electrons. Relative to homogeneous composites with an identical composition, the thermal conductivity is enhanced from 6.2 to 17.8 W/mK. Such an enhancement span is the highest compared with results reported in the literature. Due to possible "shortcut" behavior, much higher effectiveness can be achieved for the current system than found in literature results when the Elvaloy-LTEG phase is considered as filler, with the effectiveness even exceeding the upper limit of theoretical calculation for highly loaded Elvaloy-LTEG phase with relatively large PBT particle sizes. This could provide some guidelines for the fabrication of highly thermal conductive polymer composites as well as multifunctional polymer composites.

Design and development of thermally conductive hybrid nano‐composites in polysulfone matrix

“…Figure e elaborates that for the maxima of SE and , the system needs to be optimized in terms of the number of particles of fillers and this optimum ratio depends upon the dimensional parameters of the fillers and the total volume fraction of the fillers. Such high thermal conductivities of more than 5 W/mK in polymer matrix composites using graphite based fillers have been recently reported not only by researchers but also by the polymers compounding industries .…”

Facile Fabrication of 3D Porous Sponges Coated with Synergistic Carbon Black/Multiwalled Carbon Nanotubes for Tactile Sensing Applications

“…Amongst these design strategies, the dip-coating of the conductive nanoparticles on the surface of polymer-based substrate has been in growing demand for fabricating flexible piezoresistive sensors. Previous studies showed that this strategy can be achieved through a scalable, low-cost processing technology [ 25 , 32 , 33 , 34 ]. In addition, commercial sponges proved to be ideal candidates for the three-dimensional (3D) porous structure used in preparing high-performance piezoresistive sensors via the dip-coating process [ 35 , 36 ]; while polydimethylsiloxane (PDMS), as a thermosetting polymer with good flexibility and elasticity, has been in demand for improving the compressibility of pressure sensors.…”

Dual‐direction high thermal conductivity polymer composites with outstanding electrical insulation and electromagnetic shielding performance

“…Generally, high TC polymer composites are formulated by compounding high TC fillers with polymer matrix . During the past decades, ceramic‐based fillers such as aluminum oxide (Al 2 O 3 , 30 Wm −1 K −1 ), aluminum nitride (AlN, 170‐220 Wm −1 K −1 ), silicon carbide (SiC, 120 Wm −1 K −1 ), and boron nitride (BN, 380 Wm −1 K −1 ) have been widely applied to improve the TC performance of polymer composites without deteriorating the electrical insulation performance . However, it is hard to improve the TC performance of polymer composites through simple mixing high TC fillers with polymers.…”

“…[7][8][9][10][11] During the past decades, ceramic-based fillers such as aluminum oxide (Al 2 O 3 , 30 Wm −1 K −1 ), aluminum nitride (AlN, 170-220 Wm −1 K −1 ), silicon carbide (SiC, 120 Wm −1 K −1 ), and boron nitride (BN, 380 Wm −1 K −1 ) have been widely applied to improve the TC performance of polymer composites without deteriorating the electrical insulation performance. [12][13][14][15][16][17] However, it is hard to improve the TC performance of polymer composites through simple mixing high TC fillers with polymers. Great efforts have been made to fabricate high TC composites through fillers orientation, hybrid and modification method.…”