Heat dissipation becomes a critical problem because of the miniaturisation and the increase of power density in electronic devices and electric equipment, which calls for electrical insulating materials with high thermal management capability. Epoxy thermosets have been widely used as electrical insulating materials, but suffer from their low thermal conductivity. This study reviewed the research progress on the development of epoxy thermosets with high pristine thermal conductivity. First, the thermal conduction mechanism of polymers was briefly introduced. Second, the approaches used to enhance the thermal conductivity of epoxy thermosets were summarised, which mainly dealt with the formation of microscopically anisotropic but macroscopically isotropic structure in the epoxy thermosets. Third, the applications of high thermal conductivity epoxy thermoset resins were reviewed. Finally, the review provided the existing challenges and the future directions for the development of epoxy thermosets with high pristine thermal conductivity.

As modern electronics are developed towards miniaturisation, high-degree integration and intelligentisation, a large amount of heat will be generated during the operation of devices. How to efficiently remove needless heat is becoming more and more crucial for the lifetime and performance of electronic devices. Many efforts have been made to improve the thermal conductivity of polymer composites, which is an important component of electronics. Herein, the authors report on preparation of boron nitride micosphere/epoxy composites. The cross-plane thermal conductivity of the resultant composites is up to 1.03 Wm^‒1K^‒1. This is attributed to the thermally conductive network formed by the peeled hexagonal boron nitride flakes. Thanks to the superior thermal stability of boron nitride micosphere, the boron nitride micosphere/epoxy composite shows a decreased coefficient of thermal expansion (53.47 ppm/K) and an increased glass transition temperature (147.2°C) compared with the pure epoxy resin. In addition, the boron nitride micosphere/epoxy composite exhibits a lower dielectric constant compared with that of the hexagonal boron nitride/epoxy composite. This strategy can potentially pave the way for the design and fabrication of materials with high cross-plane thermal conductivity and lower dielectric properties.

Electronic packaging materials and thermal interface materials (TIMs) are widely used in thermal management. In this study, the epoxy composites with core-shell structure SiC@SiO₂ nanowires (SiC@SiO₂ NWs) as fillers could effectively enhance the thermal conductivity of epoxy composites. The unique structure of fillers results in a high thermal conductivity of epoxy composites, which is attributed to good interfacial compatibility epoxy matrix and bridging connections of SiC@SiO₂ NWs. From neat epoxy to 2.5 wt% loading of SiC@SiO₂ NWs, the thermal conductivity is significantly increased from 0.218 to 0.391 W m⁻¹ K⁻¹, increased by 79.4%. In addition, the composite with 2.5 wt% filler possess lower coefficient of thermal expansion and better thermal stability than that of neat epoxy. All these outstanding properties imply that epoxy/SiC@SiO₂ NWs composites could be the ideal candidate for TIM.

In this study, the authors reported an influence of activated carbon fibres (ACFs) with different specific surface areas on the thermal conductive and electrical insulating properties of polymeric composites. Here, the polyamide-imide composites were obtained via solution blending and cured method. The composites exhibited thermal conductivity (TC) up to 0.62 W·m⁻¹·K⁻¹. In addition, the composites were still insulating, having an electrical resistance of 0.7 MΩ. The experimental results suggested that the mechanical and electrical insulating properties decreased with the increasing of the specific surface area of the ACFs. Meanwhile, it was found that the introduction of boron nitride was conducive to the TC and electrical insulating properties of the polymeric materials.

The blend was synthesised with bismaleimide (BMI) resin and bisphenol A-based cyanate ester (BADCy) resin. The BMI/BADCy copolymer showed excellent dielectric and thermal conductivity properties. The volume resistivity of the copolymer was a little lower than BADCy system. The volume resistivity of blend was 7.8 × 10¹⁵ Ω·cm when the BMI content was 20 wt%, which still showed good insulation performance. The dielectric property of modified BADCy copolymer remained the good stability from 0.1 Hz to 1 MHz. Compared to pure BADCy system, the breakdown property of BMI/BADCy blend reached the maximum value of 77.9 kV/mm when the content of BMI was 20 wt%, which was still about 1.22 times. The thermal property and thermal conductivity property of the copolymer were higher than BADCy system.

To enhance the toughness and electrical insulation properties of cured epoxy, carboxyl-terminated polybutadiene (CTPB) liquid rubber was used to modify epoxy in this study, and the thermal conductivity, mechanical and dielectric properties of modified epoxy were investigated. The results indicate that the CTPB-epoxy exhibits higher impact strength and lower dielectric constant and loss compared with pure epoxy. Further, hexagonal boron nitride (hBN) was used to reinforce epoxy modified with 20 phr CTPB. It is found that compared with the hBN/epoxy under the same filler loading, the heat conductive hBN/CTPB/epoxy possesses a lower dielectric permittivity and dissipation factor in all frequency ranging from 10²–10⁷ Hz, a higher electrical resistivity and dielectric breakdown strength, and improved mechanical toughness. Therefore, the prepared hBN/CTPB/epoxy composites are potentially useful in practical electrical insulation applications.

Power cables are integral to modern urban power transmission and distribution systems. For power cable asset managers worldwide, a major challenge is how to manage effectively the expensive and vast network of cables, many of which are approaching, or have past, their design life. This study provides an in-depth review of recent research and development in cable failure analysis, condition monitoring and diagnosis, life assessment methods, fault location, and optimisation of maintenance and replacement strategies. These topics are essential to cable life cycle management (LCM), which aims to maximise the operational value of cable assets and is now being implemented in many power utility companies. The review expands on material presented at the 2015 JiCable conference and incorporates other recent publications. The review concludes that the full potential of cable condition monitoring, condition and life assessment has not fully realised. It is proposed that a combination of physics-based life modelling and statistical approaches, giving consideration to practical condition monitoring results and insulation response to in-service stress factors and short term stresses, such as water ingress, mechanical damage and imperfections left from manufacturing and installation processes, will be key to success in improved LCM of the vast amount of cable assets around the world.

In recent years, translational plasma medicine (TPM), as a novel application area of plasmas, has attracted much attention of experts from both academic and clinical fields. State-of-the-art of the lab-scale research and clinical trials of the cold atmospheric plasmas (CAPs) in the stomatology are reviewed in detail from the direct and indirect applications of the CAPs. Based on the discussions concerning the relationship between the plasma stomatology and the plasma medicine, it is indicated that it would be an important reference for promoting the TPM starting from the fundamental and application studies in the field of dentistry, which is also one of the most three promising application fields of plasma medicine.

Ascertaining the dielectric character of polymeric insulation materials is of particular interest for comparative studies that use accelerated ageing and samples from decommissioned installations. In the case of polymeric samples, the possibility of physical deformation within the sample holder adds additional variability to comparative measurements. Using readily obtainable instrumentation, this study undertakes a systematic sensitivity analysis of a parallel-plate capacitance measurement approach for polymeric materials that only has one capacitance plate in contact with the sample, avoiding issues of sample deformation. The analysis demonstrates that the biggest contributor of uncertainty in the measurement of the relative permittivity and loss tangent is the precision with which the plate–plate and plate–sample separation is determined. The measurements show that the determination of loss tangent can be susceptible to uncertainties arising from electrical noise, but that these can be controlled further by utilising more refined instrumentation.

In this study, dichlorodifluoromethane (R12) gas and mixtures with nitrogen (N₂) and air at different pressures and mixing ratios have been investigated and showed good alternative to gas in terms of high-voltage application. Mixed gases contain R12 gas, they offer good dielectric properties and possibility to be used in low-temperature environment. Synergistic effects and self-recoverability test have been performed. Dielectric strength under quasi-uniform field showed in the order of air in alternating current (AC), direct current (DC) and impulse was examined. Mixture R12/N₂ (80/20%) could reach over 0.90–0.95 times to that of gas at 50 lb/in² at AC and R12/air (70/30%) gives 0.80–0.90 to gas. R12 gas presents brilliant self-recoverability. The optimal ratio to switch gas is R12/N₂ (80/20%) and R12/air (70/30%) is based on the authors’ experimental condition and setup.