posted on 2023-02-06, 14:43authored byZhanyi Wang, Xuan Wang, Zhonghua Zhang, Liang Liang, Zhihang Zhao
With
the continuous development of electrical and electronic devices,
the thermal conductivity of dielectric polymer composites within devices
is becoming increasingly important. However, improving the thermal
conductivity usually requires the incorporation of a large amount
of filler in polymer material, which undoubtedly increases the production
cost while destroying the processability and the dielectric properties
of the material. In this work, an efficient heat transfer network
was constructed inside the resin matrix to overcome this drawback.
Using the opposite surface potentials of hexagonal boron nitride (h-BN)
and polyethyleneimine (PEI) in solvent, h-BN was anchored on the surface
of melamine foam (MF) by an electrostatic self-assembly technique
to construct a thermal conductive skeleton with a three-dimensional
open pore structure, and the corresponding epoxy (EP) composite was
prepared by vacuum-assisted impregnation. This EP–MF@BN composite
showed a significant increase in the heat arrival rate at an extremely
low filler loading. At a h-BN loading of 2.1 wt %, the thermal conductivity
of the composite reached 0.433 W/(m·K), which was 147% higher
than that of the pure resin matrix. This is mainly attributed to the
unique three-dimensional open-hole structure of the MF foam, which
formed a three-dimensional frame structure with extremely low thermal
resistance after anchoring by h-BN, thus providing a great degree
of weakening of the scattering behavior during phonon transport. In
addition, the transport behavior of carriers inside the composite
under strong electric field conditions was analyzed in the current
study. This strategy of constructing an efficient heat transfer network
inside the polymer matrix provides an idea and method for the preparation
of composites in the field of electrical insulation.