Thermal conductivity enhancement of polyimide films filled with BN and AlN fillers

Abstract

A series of polyimide (PI) composite films were prepared using PI as matrix and boron nitride (BN) and aluminum nitride (AlN) as the doped phases. The modification of the thermal conductive filler particles was characterized by Fourier transform infrared (FTIR). The results showed that the silane coupling agent KH550 was successfully coated on the surface of BN and AlN. X-ray photoelectron spectrometer characterization was used to further prove that silane coupling agents were successfully attached to BN and AlN surfaces, forming a new chemical bond. Scanning electron microscope (SEM) was used to analyze the dispersion of filler particles in the matrix. It was found that agglomeration phenomenon occurred when the content of BN particles were high, but this problem was improved after the surface modification of BN. The breakdown field strength and volume resistivity of PI/BN composite film increased first and then decreased with the increase of BN content and reached the maximum when the volume fraction of BN was 5%, which was 191.53 kV/mm and 8.832 × 1013 Ω·m, respectively. When the BN content was 9 vol%, the thermal conductivity of the PI/BN composite film was 0.496 W/(m·K), which was 1.4 times larger than that of the pure PI film. The thermal conductivity of the PI/BN/AlN composite film at the BN and AlN contents of 5 vol% and 1 vol%, respectively, is 0.144 W/(m·K) higher than that of 7 vol% PI/BN. It indicated that the synergistic effect of the composite fillers played a significant role, and at the same time, under the premise of ensuring higher thermal conductivity, the amount of thermally conductive particles could be reduced to some extent. After the surface modification of the filler particles, the properties of the composite film showed the same trend compared with the unmodified one, while the only difference was that there was a certain increase in the numerical value.

3D Thermal Network Supported by CF Felt for Improving the Thermal Performance of CF/C/Epoxy Composites

“…The method of adding fillers is a fast way to improve the thermal conductivity of polymers. Metal materials (such as copper powder [ 7 , 8 , 9 ], silver powder [ 10 , 11 ], metal sheet and wire [ 12 , 13 , 14 ]), carbon materials (such as carbon fiber (CF) [ 15 , 16 , 17 ], graphene material [ 18 , 19 ], graphite material [ 20 , 21 ], carbon nanotubes [ 22 , 23 ], carbon black [ 24 , 25 ]), inorganic fillers (such as aluminum nitride [ 26 , 27 ], boron nitride [ 28 , 29 , 30 ], silicon nitride [ 31 , 32 ], silicon carbide [ 33 ], alumina [ 34 , 35 ]) and other high thermal conductivity fillers are often used to improve the thermal conductivity of polymers. When the particulate filler content is small, it is difficult to significantly improve the thermal conductivity of the matrix.…”

Enhanced thermal conductivity of polyimide composite film filled with hybrid fillers

“…In recent years, the filler hybridization strategy to synergistically improve polymer performance has gradually been considered a simple and effective method. 18–20 Jin introduced a few graphene nanoplatelets (1 wt%) and carbon nanotubes (1 wt%) into the h-BN/polycarbonate composites, the thermal conductivity of composites reached up to 1.42 W(m·k) − 1 . At the high h-BN content, the dielectric properties were kept at a low level.…”

Polyimide fabric-reinforced polyimide matrix composites with excellent thermal, mechanical, and dielectric properties

“…In particular, because PI fibers can be used within a wide range of temperatures, they match well with the ultrahigh temperature and pressure applied in the processing conditions of high performance resins and achieve long-term service stability under extreme environments. [6][7][8][9][10][11][12][13][14] In addition, the low dielectric constant and loss of PI fibers also make them a promising substance in the manufacturing of structural-functional integration materials for wavetransparent applications, such as in the radomes of satellite or 5G base stations, providing a new approach to the material design and selection of advanced composites. [15][16][17][18] At present, the primary problem of applying PI resins prepared using a polymerization monomeric reactant (PMR) method is the difficulty in molding.…”