Sandwiched epoxy–alumina composites with synergistically enhanced thermal conductivity and breakdown strength

Abstract

Development of polymer-based composites with simultaneously high thermal conductivity and breakdown strength has attracted considerable attentions owing to their important applications in both electronic and electric industries. In this study, we successfully design novel epoxy-based composites with nanoAl 2 O 3 /epoxy composite layer sandwiched between micro-Al 2 O 3 /epoxy composite layers, which show synergistically and significantly enhanced thermal conductivity and breakdown strength. Compared with the traditional composites, the bottleneck that both thermal conductivity and breakdown strength cannot be simultaneously enhanced can be overcome successfully. An optimized sandwiched alumina-epoxy composite with 70 wt% micro-Al 2 O 3 fillers in the outer layers and 3 wt% nano-Al 2 O 3 in the middle layer simultaneously displays a high thermal conductivity of 0.447 W m -1 K -1 (2.4 times of that of epoxy) and a high breakdown strength of 68.50 kV mm -1 , which is 6.3 % higher than that of neat epoxy (64.45 kV mm -1 ). The experimental results on the thermal conductivity of multi-layered alumina-epoxy composites were in well accordance with the theoretical values predicted from the series conduction model. This novel technique simultaneously improves thermal conductivity and breakdown strength, which is of critical importance for design of perspective composites for electronic and electric equipments.

Thermal, electrical, and mechanical properties of addition‐type liquid silicone rubber co‐filled with Al2O3 particles and BN sheets

“…As thermally conductive fillers, AlN, Al 2 O 3 , hexagonal-BN, carbon nanotubes and graphene have been often investigated to increase the thermal conductivity of polymer matrix. [9][10][11][12] Zhao et al investigated the effect of (3-mercaptopropyl)trimethoxysilane (MPTS)and copper-coated carbon fiber (M-Cu-CF) on thermal conductivity of the silicone rubber composites. It was found that the thermal conductivity of the M-Cu-CF/SR composites reached 1.99 W m −1 K) −1 with only 4.0 wt% filler loading.…”

Alignment of Boron Nitride Nanofibers in Epoxy Composite Films for Thermal Conductivity and Dielectric Breakdown Strength Improvement

“…In recent years, to achieve a better performance, the tendency in electronic technology has been towards integrating more transistors into a single chip. Yet this has caused the escalation of energy dissipation and significant heat fluxes in a device, which negatively influences its lifetime and reliability [ 1 , 2 , 3 , 4 , 5 ]. So, novel materials with better electrical and thermal performance are needed.…”

“…To improve thermal conductivity of epoxy resin, the fillers of micro-scale with high thermal conductivity can be considered. Nevertheless, the dilemma for using micro-sized inorganic particles is that the increase of thermal conductivity is usually attained at the expense of a significant decrease in breakdown strength, which thus limits their applications in high output electrical devices [ 2 , 10 , 11 ]. Thus, it can be seen that the development of epoxy-based composites with high thermal conductivity and dielectric breakdown strength is impending.…”

Dispersing Nanoparticles by Chiral Liquid Crystalline Elastomers for Performance Enhancement of Epoxy Nanocomposites

“…Covalent bonds can enhance the adherence between nanoparticles and polymers. A great deal of studies demonstrated that modified nanoparticles could decrease agglomeration of the nanoparticles and enhance their interfacial bonding in polymer matrix and organic solvent . Salimi et al.…”