Molecular Alignment Induced High Thermal Conductivity in Amorphous/ Low Crystalline Polyimide Fibers
ABSTRACT. It is of considerable scientific and technological importance to enhance the thermal conductivity ( k ) of polymers for the application in thermal management. In this work, we study the thermal transport in amorphous/low-crystalized polyimide (PI) composite fibers (crystallinity lower than 2%-10%) by using the transient electro-thermal (TET) technique and the steady-state electro-thermal (SET) technique from 320 K to 7 K. It is found that the amorphous/low-crystalized PI fibers can achieve a high k (2.13 W/m K) due to oriented chain alignment and inter-chain hydrogen bonds from the condensation polymerization, wet-spinning and low-ratio thermal drawing process. By using the thermal reffusivity ( Θ ) model, the phonon propagation in PI fibers is investigated. The structural domain size (SDZ) of the amorphous/low-crystalized PI fibers is determined based on the residual Θ at 0 K limit, which is calculated to be 3.85 nm and 9 nm for the undrawn and post-drawn PI fiber, respectively. The SDZ value is close to the radius of gyration ( R g ) instead of the atomic scale characteristic length of PI. This result indicates that for amorphous/low crystalized PI fibers with hydrogen bonds, the R g could have played a more important role in determining k
Year of publication: |
[2022]
|
---|---|
Authors: | Xiang, Liping ; Fang, Yuting ; Xu, Ke ; Zheng, Zhuanghao ; Dong, Jie ; Xie, Yangsu |
Publisher: |
[S.l.] : SSRN |
Saved in:
freely available
Saved in favorites
Similar items by person
-
Hou, Xin-wen, (2010)
-
Regional Water Demand Prediction and Analysis Based on Cobb-Douglas Model
Zhang, Qinghua, (2013)
-
Does piped water improve adolescent health? Empirical evidence from rural China
Dong, Jie, (2021)
- More ...