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ACS Appl Mater Interfaces. 2017 Aug 30;9(34):29071-29081. doi: 10.1021/acsami.7b07947. Epub 2017 Aug 21.

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

Author information

1
College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University , Chengdu 610065, People's Republic of China.
2
Patent Examination Cooperation Center of the Patent Office, SIPO , Sichuan 610213, People's Republic of China.

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.

KEYWORDS:

EMI shielding ability; electrical conductivity; polymer composites; segregated structure; thermal conductivity

PMID:
28792203
DOI:
10.1021/acsami.7b07947

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