We report novel research results demonstrating the production of polymer nanocomposites with high thermal conductivity. The use of diluents, a conventionally used method to reduce viscosity and increase processability, had clear limitations that could not be used for solid epoxy, but in this study, the melting point of the epoxy itself was reduced through the introduction of the eutectic system, allowing the solid epoxy to be converted into a liquid phase. By utilizing eutectic liquid (EL) derived from ketone-containing epoxy resin (DBPE) and diphenylamine (DPA), we achieved maximal filler content. Unlike DBPE's solid form at 135 degrees C, EL displayed liquidity with a viscosity of 50 Pa center dot s at 50 degrees C, enabling curing with isophorone diamine (IPDA) below DBPE's melting point. While DBPE/IPDA yielded a tensile strength of 7.2 MPa due to uneven mixing, EL/IPDA reached 44.3 MPa, marking a 520 % improvement. EL's viscosity dropped dramatically, reaching 0.06 Pa center dot s at 98 degrees C. The EL/IPDA mixture's viscosity at 98 degrees C was 150 Pa center dot s, allowing up to 80 wt% hexagonal boron nitride (h-BN) filler. This led to a thermal conductivity of 16 W/m center dot K, 20 wt% higher than DGEBA's 60 wt% filling rate. Notably, EL/h-BN composites achieved 16 times the thermal conductivity of DGEBA/h-BN composites, which is 1 W/m center dot K. Lowering the melting point and viscosity expanded curing agent choices, enhanced tensile strength, increased filler content, and heightened thermal conductivity, showcasing EL's remarkable potential.

The epoxy-based crosslinked polymer with the mesogenic group has been studied as a candidate resin material with high thermal conductivity due to the ordered structure of the mesogenic groups. In this study, we conducted all atomic molecular dynamics simulations with iterative crosslinking procedures on various epoxy resins with mesogenic motifs to investigate the effect of molecular alignment on thermal conductivity. The stacked structure of aromatic groups in the crosslinked polymer was analyzed based on the angle-dependent radial distribution function (ARDF), where the resins were categorized into three groups depending on their monomer shapes. The thermal conductivities of resins were higher than those of conventional polymers due to the alignment of aromatic groups, but no distinct correlation with the ARDF was found. Therefore, we conducted a further study about two structural factors that affect the alignment and the TC by comparing the resins within the same groups: the monomer with an alkyl spacer and functional groups in hardeners. The alkyl chains introduced in the epoxy monomers induced more stable stacking of aromatic groups, but thermal conductivity was lowered as they inhibited phonon transfer on the microscopic scale. In the other case, the functional groups in the hardener lowered the TC when the polar interaction with other polar groups in the monomer was strong enough to compete with the pi-pi interaction. These results represent how various chemical motifs in mesogenic groups affect their alignment on the atomistic scale, and also how they have effects on the TC consequently.

To achieve a high thermal conductivity, thermally conductive polymer composites have been recently exploited, focusing on connecting a 3D network of thermally conductive fillers by applying external pressure or constructing a pre-made 3D filler framework to reduce phonon scattering within the polymer matrix. However, these approaches severely restrict the use of polymers, particularly epoxy composites, in many commercial applications such as the thermal management of electronic device packaging. In this study, a high-thermal-conductivity epoxy composite is fabricated by incorporating hexagonal boron nitride (h-BN) decorated with tin nanoparticles (Sn NPs). Under a hybrid filler (Sn NPs on h-BN) loading (68 wt %), the composite exhibits a high thermal conductivity of 11.9 +/- 0.29 W m-1 K-1 while maintaining a relatively low dielectric constant (Dk - 7.52) and loss (Df - 0.023) at 1 MHz with a coefficient of thermal expansion of 34 ppm degrees C- 1. The Sn NPs on h-BN in the epoxy resin matrix are thermally percolated by the in-situ growth of Sn NPs under carefully controlled curing temperature and time, resulting in significantly improved thermal conductivity of the epoxy composite under pressure-less curing conditions.

In this paper, problems of v-shaped pits originated from threading dislocation that can occur during the fabrication of light emitting diode and ways to solve these problems were introduced. First of all the electrical properties were measured by observable point of a v-shaped pit, then a form of v-shaped pit was separated according to the electrical properties. We found a correlation between the electrical properties and the form of v-shaped pit. Furthermore we knew that the particular form of v-shaped pit led to a leakage current. Consequentially, the improvement of these leakage current from v-shaped pits was proposed.

Electrically conductive acrylonitrile-butacliene rubbers (NBRs) containing carbon black (CB) as conductive filler were prepared in order to investigate their electrical and mechanical properties. The effects of conductive CB loading, temperature, acrylonitrile content, crosslinking density of vulcanizates, and plasticizer on conductivity were studied. The change in electrical conductivity of NBRs with different amounts of CB showed that there is a certain critical point (percolation threshold) where a significant decrease in electrical resistivity (increase in conductivity) is observed. Mechanical properties such as tensile strength, elongation to break, and surface hardness of vulcanized NBRs were measured. It was found that the percolation threshold was 5 phr of CB for the NBR/CB composites.