Application Of Insulation Materials Research Articles

Advanced Dielectric Materials for Triboelectric Nanogenerators: Principles, Methods, and Applications.

Triboelectric nanogenerator (TENG) manifests distinct advantages such as multiple structural selectivity, diverse selection of materials, environmental adaptability, low cost, and remarkable conversion efficiency, which becomes a promising technology for micro-nano energy harvesting and self-powered sensing. Tribo-dielectric materials are the fundamental and core components for high-performance TENGs. In particular, the charge generation, dissipation, storage, migration of the dielectrics, and dynamic equilibrium behaviors determine the overall performance. Herein, a comprehensive summary is presented to elucidate the dielectric charge transport mechanism and tribo-dielectric material modification principle toward high-performance TENGs. The contact electrification and charge transport mechanism of dielectric materials is started first, followed by introducing the basic principle and dielectric materials of TENGs. Subsequently, modification mechanisms and strategies for high-performance tribo-dielectric materials are highlighted regarding physical/chemical, surface/bulk, dielectric coupling, and structure optimization. Furthermore, representative applications of dielectric materials based TENGs as power sources, self-powered sensors are demonstrated. The existing challenges and promising potential opportunities for advanced tribo-dielectric materials are outlined, guiding the design, fabrication, and applications of tribo-dielectric materials.

Microstructural evolution during the crystallization process of sol-gel derived PbZrO3 nanocomposite thin films

For the application of dielectric materials in energy storage, nanocomposition is one of the effective methods to improve their electric breakdown field strength. In this study, PbZrO3-Al2O3 nanocomposite films were prepared by combined thermal evaporation deposition and a sol–gel method. By changing the annealing time, the crystallization process of PbZrO3 matrix and the formation mechanism of Al2O3 nanoparticles were studied, and the microstructure evolution process of composite films was elucidated. The results indicate that before the final annealing at 700 ℃, Al atoms have diffused into the amorphous PbZrO3 film, and some fine grains of the perovskite phase have been generated at the bottom of the film. As the annealing time increases, the perovskite grains grow along the out of plane direction of the thin film to form columnar grains, and Al atoms diffuse into the perovskite phase lattice; As the annealing time further increases, Al2O3 nanoparticles began to precipitate at the interlayer interfaces of PbZrO3 coating layers, forming a layered distribution. The changes in electric properties with annealing time also demonstrate the microstructural evolution process of the composite film during annealing. Therefore, controlling annealing time is an effective means to control the microstructure and electric properties of composite films prepared by the new method for the application of energy storage.

Comparative analysis of machine learning models for predicting dielectric properties in MoS2 nanofiller-reinforced epoxy composites

This research investigates the dielectric properties of nano epoxy composites by incorporating various concentrations of MoS2 into epoxy resin. The study explores the impact of synthesized nanoparticles on undoped epoxy composites, specifically focusing on their potential applications in dielectric materials. The experimental synthesis and characterization of nanoepoxy composites typically involve time-consuming and expensive methods. This study compares five machine learning (ML) models—random forests, decision trees, extra trees, XGBoost, and gradient boosting—in order to predict the frequency-dependent dielectric constants in these composites under different nanofiller variations in order to address this challenge. To ensure robust model performance, training is carried out on different subsets of the dataset, ranging from 60% to 30%, while the remaining portions are reserved for testing purposes (40% to 70%). The main objective of the study is to assess the performance of each regressor technique using metrics such as adjusted R2 score, MSE, RMSE, and MAE, in which the ET regressor excels. The ET method demonstrates exceptional performance, achieving an adjusted R2 value of 0.9977 and 0.9912 for target variables ε′ and ε′′, respectively when tested with a size of 0.4. The findings underscore the potential of ML models for precise and efficient prediction of frequency-dependent dielectric constants of nanoepoxy composites with various concentrations of nanofillers, offering an alternative to time-consuming and expensive laboratory work.

A novel low loss rare-earth germanate La4GeO8 microwave dielectric ceramic with orthorhombic structure

This study delves into the synthesis and characterization of rare earth germanate La4GeO8 ceramics, employing the solid-phase reaction method, with a focus on their microwave dielectric properties and crystallographic characteristics. The research employs X-ray diffraction (XRD) and transmission electron microscopy (TEM) to ascertain the orthorhombic crystal structure within the Pnma space group. Rietveld refinement analysis precisely determines the lattice constants (a = 18.3006 Å, b = 7.6697 Å, c = 5.8513 Å) and unit cell volume (V = 821.28429 Å3). Raman spectroscopy provides insights into the correlation between the quality factor (Q × f) and the Full Width at Half Maximum (FWHM) of the Ag(O) mode at 733 cm⁻1. A notable highlight of the study is the exceptional microwave dielectric performance of La4GeO8 ceramic sintered at 1540 °C, characterized by a relative dielectric constant (εr) of 13.24, a Q × f product of 47,826 GHz at 10.16 GHz, and a temperature coefficient of frequency (τf) of −82.3 ppm/°C. This comprehensive investigation offers valuable insights into the structural and microwave dielectric properties of AB-type rare earth germanate La4GeO8 ceramics, underscoring their potential in advanced dielectric material applications.

The ultra-high electric breakdown strength and superior energy storage properties of (Bi0.2Na0.2K0.2La0.2Sr0.2)TiO3 high-entropy ferroelectric thin films

The electric breakdown strength (Eb) is an important factor that determines the practical applications of dielectric materials in electrical energy storage and electronics. However, there is a tradeoff between Eb and the dielectric constant in the dielectrics, and Eb is typically lower than 10 MV/cm. In this work, ferroelectric thin film (Bi0.2Na0.2K0.2La0.2Sr0.2)TiO3 with a dielectric constant of 115 is found to exhibit an ultra-high Eb = 10.99 MV/cm, attributing to the high-entropy effects that could result in dense nanostructures with refined grains, low concentration of oxygen vacancies, low leakage current and small polar nano-regions in the thin film. A recoverable energy storage density of 5.88 J/cm3 with an excellent energy storage efficiency of 93% are obtained for the dielectric capacitor containing the thin-film dielectrics. Remarkably, the dielectric capacitor possesses a theoretical energy storage density of 615 J/cm3 compatible to those of electrochemical supercapacitors. The high-entropy ferroelectric thin films with ultra-high Eb and superior energy storage properties are much promising dielectrics used in next-generation energy storage devices and power electronics.

Dielectric Breakdown Strength of Polypropylene Blended with Ethylene Octene Elastomers

Polymer blends have become a major focus of research in exploring the potential for new dielectric material applications, particularly in the insulation of high voltage systems. In the current research area, polypropylene (PP) is being investigated as an insulation material for high voltage alternating current and direct current power cables. However, PP must be treated with rubbery materials such as elastomers to lessen its overall stiffness for power cable extrusion. While various promising results have been published on the potential use of PP/elastomer blends as dielectric materials, the dielectric effects of adding ethylene octene elastomer to PP have been less explored. This paper discusses the alternating current (AC) and direct current (DC) breakdown strength of PP that contains different amounts of ethylene octene elastomer (10, 30, and 50 wt%). The addition of ethylene octene elastomer to PP affects the breakdown performance of the blend systems under both AC and DC fields. Significantly, an increase in elastomer contents results in a notable reduction in the AC and DC breakdown strength. A discussion is presented on the mechanisms underlying the change in the breakdown strength caused by the different amounts of ethylene octene elastomer blended with PP.

Promising biomass waste–derived insulation materials for application in construction and buildings

AbstractCurrent insulation materials applied in construction engineering and the building industry are generally petrochemical-based polymers and recycled thermal insulation materials. The environmental effects of these materials’ production processes are substantial, despite their high thermal insulation performance. Consequently, the researchers conclude that it is essential to develop and produce insulating materials with superior thermal properties, minimal environmental impact, and a reasonable cost. The study concentrated on the application of insulation materials derived from biomass in the development of thermal insulation. The purpose of this review is to investigate and develop the possibilities of using biomass wastes as renewable and eco-friendly thermal insulation materials for construction engineering and the building industry. The thermal conductivity of those materials was measured using the hot plate and hot box methods, two of the most widely used hot processing methods. With a relatively low thermal conductivity (< 0.100 W·m−1·K−1), this review provides critical scientific insight into potential building insulation materials derived from biodegradable and abundant resources. It was observed that these materials are appealing for use in building and construction because they have a number of potential advantages from technical, economic, environmental, and green credentials perspectives. The collection of information enables some conclusions regarding the different biomass waste–derived insulation materials that have already been investigated and identifies gaps in the literature. Finally, the scope of commercialization pathways and future research directions to validate the proposed material alternatives’ claim for commercial-scale applications has been identified in this review. Graphical Abstract

Investigation of the Charge Accumulation Based on Stiffness Variation of the Micro-Shell Resonator Gyroscope.

In capacitive microelectromechanical system (MEMS) devices, the application of dielectric materials causes long-term charging problems in the dielectric layers or substrates, which especially affect the repeatability and stability of high-performance devices. Due to the difficulties of observation and characterization of charge accumulation, an accurate characterization method is needed to study the effect of charge and propose suppression methods. In this paper, we analyze the influence of charge accumulation on the MSRG and propose a characterization method for charge accumulation based on stiffness variation. Experiments are carried out to characterize the charge accumulation in MSRG, and the effect of temperature on the process is also investigated. In the experiment, the charge accumulation is characterized accurately by the variation of the frequency split and stiffness axes. Furthermore, the acceleration of the charge accumulation is observed at high temperatures, as is the higher additional voltage from the charge accumulation.

Properties and Applications of Dielectric Materials Derived from Metal-Organic Frameworks - A Review

An electrical insulator known as a dielectric material is a substance that can be solid, liquid, or gaseous. Having a high specific resistance, a dielectric material is a non-metallic substance. A dielectric function as the perfect capacitor, storing and dissipating electrical energy. Due to the rising need for capacitors, semiconductor devices, Liquid Crystal Displays, electrical transformers, and other products, properties including electric susceptibility, dielectric polarisation, dispersion, relaxation, and tunability have received a great deal of attention. Advanced materials must be developed in order to further enhance their performance. Metal-organic frameworks (MOFs), a class of porous crystalline solids, have shown to be ideal models for synthesising functional materials that may be used to make supercapacitor electrodes. Greater electrical conductivity, a higher charge capacity, and variable electrochemical activity are just a few benefits that bimetallic MOFs and their derivatives have over monometallic MOFs. This study focuses on the usage of MOF-derived bimetallic in dielectric materials, with particular attention paid to understanding the cause of the enhanced performance and covering the most recent advancements in the area with a variety of applications.

Green buildings model: Impact of rigid polyurethane foam on indoor environment and sustainable development in energy sector

The construction and building industry in the modern world heavily relies on advanced techniques and materials such as polymers. However, with the world's population alarmingly increasing, contributing to the greenhouse effect, and severe weather conditions amplifying, it has become crucial to reduce the heat effects in both new and old buildings. To achieve this, 50–70% more energy is necessary, which highlights the importance of energy-efficient construction practices and materials. Consequently, a comprehensive study was conducted to evaluate the efficacy of Polyurethane in indoor environments and energy conservation. Current study was performed due to an innovative application of insulation materials as to reduce the heat and energy costs in construction works. Thermal conductivity at mean temperature 35 °C was found 0.0272 (W/m K) with maximum in burnt clay brick (1.43 W/m K) by using hotplate apparatus. Specific heat was also found less 0.85 (KJ/Kg K) at density 32 kg/m3 while results were at par in reinforcement cement concrete and burnt clay brick 0.91, 0.91 (KJ/Kg K) respectively. Similarly, heat transmittance values of different roof sections by using polyurethane insulation showing satisfaction the ECBC in Buildings deviating standard U-value 1.20% to 0.418 (W/m2 K) with its excellent performance. Polyurethane treatments have been found to exert a significant impact on the computation of thermal resistance and overall heat transfer coefficients. In contrast, non-insulated treatments yielded inconclusive results with little to no significance. This highlights the importance of insulation materials in energy-efficient construction practices. Energy consumption in winter and summer also has shown the significant impact by using polyurethane application with cumulative saving of 60–62% electricity. Economic Benefit of polyurethane in RCC and Conventional buildings describes positive and highly significant impact in present study. Application of polyurethane in new and old buildings ultimate enhanced the better quality of life and living standards from people of applied countries and is strongly recommended for future prospects and endeavors as Eco-friendly and energy efficient for sustainable development.

Study on Secondary Electron Yield of Dielectric Materials

The secondary electron emission coefficient of dielectric materials will have an important impact on the performance of electronic devices and equipment. In order to understand the secondary electron emission coefficient of common dielectric materials, the collection electrode negative bias method is introduced in this study. First, the measurement method of secondary electron emission coefficient of dielectric materials is analyzed, and 20 common dielectric materials are introduced, the secondary electron emission coefficients of 20 kinds of common dielectric materials were measured and analyzed, which laid the foundation for the subsequent application of dielectric materials. The results show that among common dielectric materials, the secondary electron emission coefficients of alumina, silica and muscovite are relatively high, while those of polyimide, polycarbonate and polyester are relatively low; The surface roughness of the material will also have an important impact on the secondary electron emission coefficient. With the gradual increase of the surface roughness of the material, the undulation of the material surface will have a shielding effect and absorption effect on the secondary electrons, which will eventually lead to the gradual reduction of the secondary electron emission coefficient of the material. The research results can provide data support for the establishment of the database of secondary electron emission characteristics of common dielectric materials.

Bio-based insulation materials and model predictive control of active cooling systems in machine tools

The adoption of biological principles and materials plays a decisive role in the conversion to sustainable production technologies. Measures for the biological transformation of a machine tool were implemented following the example of warm-blooded animal, which automatically control their core temperature and, depending on their habitat, possess an insulating layer of fat. In this work, thermal insulation measures were implemented on machine tools using renewable materials and their effects were evaluated.Insulation materials of petrochemical origin such as polystyrene (Styrofoam) were replaced by alternatives made of mycelium with comparable heat insulating properties. On the lower machine bed, a slowdown of the cooling rate was observed after application of insulation materials at external temperature drops. The insulation between the machine bed and the control cabinet was also found to reduce tool centre point (TCP) displacement. This cost-efficient measure reduces the error during the process and the effort required to correct the linear axes and to heat and cool the machine.To homogenize the temporal and spatial temperature profile of machine tools, a control system was developed to compensate for thermally induced errors by means of adaptive active cooling. Therefore, a model predictive control using an embedded artificial intelligence (AI) model to forecast the structural temperature development was implemented. Through a hybrid training database combining experimental and simulative data series, a both flexible and precise determination of the thermal system behaviour could be achieved. On a real production machine, the active cooling system is divided into five individually controllable and adjustable cooling circuits. This approach allows cooling the machine structure according to time and local demand to minimize thermally induced TCP displacement under variable operating conditions.This paper serves to define and evaluate possibilities and requirements for the integration of bio-based insulation materials and control algorithms for homoiothermic conditions in production machines.

Metal-organic frameworks mediated interface engineering of polymer nanocomposites for enhanced dielectric constant and low dielectric loss

Interface modulation is a key issue for the incorporation of inorganic nanofillers into polymeric matrixes, especially in the applications of dielectric materials. Metal-organic frameworks (MOFs) with special organic and inorganic characteristics represent enormous potential in the interface engineering of polymer-based nanocomposites with desirable dielectric performance. Herein, we report a novel strategy to synthesize graphene oxide nanosheets with UiO-66-NH2 MOF decoration (G@M) using an in-situ and ex-situ method, which are utilized as the nanofillers in the super-engineering polymeric matrix namely polyarylene ether nitrile (PEN). In-situ MOF decoration improves the compatibility between graphene oxide and PEN matrix, and the resulting G@M/PEN nanocomposite shows an enhanced dielectric constant of 7.94 and an ultra-low dielectric loss of 0.014 (1000 Hz) at a low filling content (4 wt%) with outstanding tensile strength (106 MPa) and high glass transition temperature (208°C). Besides, owing to the in-situ interface tailoring, the G@M/PEN nanocomposite exhibits a much higher energy storage capability, about 107% higher than that of conventional graphene oxide-incorporated nanocomposite. This research provides new insight into the interface design of polymer-based nanocomposites for dielectric applications.

Thermal insulation capability of nanostructured insulations and their combination as hybrid insulation systems

The applications of insulation materials in buildings and vehicles are more important than ever. Therefore, the application of thermal insulation materials having high-performance heat-blocking properties such as nano-structured insulations like aerogels and graphite polystyrene is essential. In this paper a comprehensive thermal characterization will be presented, executed on two types of fibrous aerogels (slentex, pyrogel) as well as on graphite-expanded polystyrene, to compare their thermal insulation capability. Moreover, their possible sandwich-structured application as hybrid insulation systems was tested, too. The surface analysis of the samples is going to be presented through microscopic and wetting experiments. Thermal conductivity as well as specific heat capacity measurement results of both individual and sandwich structures will be shown. Slentex aerogel has the lowest thermal conductivity and performed best of all. The results of the hybrid structures are promising. The moisture uptake of the pyrogel aerogel is the highest. Based on the measured values theoretical models will be applied for validation, moreover, a face-to-face analysis will also be presented. Furthermore, calculations regarding thermal properties will also be highlighted. Results of both infrared absorption tests and differentiated scanning calorimetry would help the decision makers and it proves the high infrared absorption of graphite polystyrene.

Thermal stable and ultralow dielectric loss in (Gd0.5Ta0.5)xTi1-xO2 giant permittivity ceramics by defect engineering

High dielectric loss and poor temperature stability are the current barriers to the application of dielectric materials. In present work, we synthesized a system of acceptor Gd3+ and donor Ta5+ co-doped (Gd0.5Ta0.5)xTi1-xO2 (GTTOx, x = 0, 0.01, 0.02, 0.04, 0.06) ceramics to enhance dielectric response. It was found that a colossal permittivity (CP, 2.65 × 104@1 kHz, 2.37 × 104@1 MHz), a very low dielectric loss (tanδ, 0.007@1 kHz, 0.03@1 MHz), good stability of frequency (20–106 Hz) and temperature (RT–250 °C, Δε′ (T)/ε′30 < ± 15%, at 1 kHz) were achieved simultaneously in GTTO0.01 ceramic. Complex impedance spectroscopy, XPS, SEM, and Raman spectroscopy were used to investigate the reasons for the improved dielectric properties. The result indicated that the main reasons for CP and low dielectric loss are the synergistic effect of the electron pinning defect-dipole (EPDD) model, the internal blocking layer capacitance (IBLC) mechanism, and electrode response. This work provides a promising approach for the design of defect-related high-performance giant dielectric ceramics.

Colossal Permittivity Characteristics and Origin of (Sr, Sb) Co-Doped TiO2 Ceramics

With the continuous development of electronic technology, the application of dielectric materials is also becoming more and more abstractive. It is also a great challenge to find a new type of colossal permittivity material with high dielectric permittivity, lower dielectric loss and excellent temperature and frequency stability. In this work, the (Sr1/3Sb2/3) x Ti1−x O2 (SSTO) colossal permittivity ceramics for x = 0, 0.5%, 1.0%, 1.5%, 2.0%, 4.0% were prepared by conventional solid state reaction method. The crystal structure, microstructure, dielectric properties, varistor properties were analyzed, and the formation mechanism of colossal dielectric was revealed. When the doping amount is 2%, SSTO has the optimal dielectric performance with dielectric constant of approximately 2.2 × 104, dielectric loss of about 0.03 at 1 kHz. X-ray photoelectron spectroscopy (XPS) and Impedance spectra (IS) results showed that defect clusters and interface polarization are the main reasons for the improvement of dielectric properties of (Sr, Sb) co-doped TiO2 ceramics. Therefore, this work is of great significance for the development and application of TiO2-based new colossal dielectric materials.

Analysis of the critical temperature on load bearing LSF walls under fire

Light Steel Frame (LSF) walls are widely used in building structures, used as partition walls and load bearing walls. The LSF is usually protected by layers of homogeneous plates or composite plates, with or without insulation materials in the cavity. This investigation presents the simulation results of composite LSF walls in reduced scale and full scale, based on variable load levels (20 to 80%). The numerical model uses a hybrid model approximation, based on the experimental tests to accurately determine the temperature field. The numerical model is validated with experimental results, at reduced and full scale, both at room temperature and under fire conditions. This modelling technique can follow the thermal and mechanical degradation of the protection layers of the LSF wall and determine the fire rating for load bearing (R) and insulation (I). The fire resistance (R) decreases with the increase of the load level. The insulation ability is also predicted for different protection materials. Relevant conclusions are presented to increase the insulation ability of LSF walls, especially when using non combustible double protection layers. The insulation ability to sustain fire usually increases with the number of studs and with the application of insulation material in the cavity region. The ability to sustain the load under fire also increases with the number of studs, especially for higher load levels. The ability to sustain the load also increases with the number of protection layers, changing from 16% at 20% load level, to 42% at 50% load level.A new proposal is presented for the critical temperature of the LSF, based on the maximum temperature of the LSF during the fire, allowing the calculation of the critical temperature, based on the load level of the specimen. This relation can predict the fire resistance time, based on the preliminary thermal analysis of the specimen. The reduced scale specimens present higher critical temperatures when compared to the full scale specimens, due to the typical failure mode (local modes for the reduced scale and global modes for the large scale).

Dielectric Response Behavior and Displacement‐Type Metal‐Free Organic‐Inorganic Hybrid Phase Transition Material: trans‐(NH3C6H10NH3)[NO3]2

AbstractPhase transition compounds have been attracting interest in scientific research due to their wide applications in dielectric materials. Herein, a new displacement‐type metal‐free organic‐inorganic hybrid phase transition material trans‐(NH3C6H10NH3)[NO3]2 (1) with Tc=245 K has been successfully synthesized. The single‐crystal X‐ray diffraction elucidates that the space group of 1 turns from P in the high temperature phase to P21/c in the low temperature phase. And the reason of phase transition is related to the displacements of trans‐(NH3C6H10NH3)2+ cations and [NO3]− anions. In addition, 1 shows a dielectric anomaly around the Tc. We expect that this finding will contribute to the research of displacement‐type metal‐free phase transition materials.

Powder sintering and gel casting methods in making glass foam using waste glass: A review on parameters, performance, and challenges

The application of insulation materials in buildings and energy storage facilities is gaining global attention to reduce energy consumption, heat loss, and CO 2 emissions. Given the high insulation performance, glass foam is gaining popularity replacing combustible, high energy-consuming, and costly conventional insulation materials. The industrial process of glass foam manufacturing is an energy-consuming and non-ecofriendly process which requires the annealing of glass around its melting temperature. Therefore, researchers have developed powder sintering and gel casting methods to sinter glass foam mix at a temperature slightly above its glass transition point. However, research findings on these two methods are scattered because of the different parameters being used by researchers. The properties and performances of glass foam depend on the processing parameters, especially on the materials design and sintering conditions. Therefore, this study aimed to provide a comprehensive review on the key parameters for material selection and sintering of glass foams and provide necessary guidelines for the best practice and a direction for future research. Moreover, this review covers the current strategies and challenges associated with the powder sintering and gel casting methods including their sustainability and environmental performance.

농촌주택 및 목조주택 표준모델 구조체의 습·열 환경 성능 개선 방안

The purpose of this study was to investigate whether the standard models for rural housing and wooden housing model have performance for hygrothermal and to propose a way of improvement relevant to hygrothermal performance for those models. All of the models to be analyzed were found to have some parts that were absent of stability in terms of performance for hygrothermal. In the process of analyzing the causes and proposing improvement measures, the following conclusions were derived. Fist, The exterior surface of the structure should be composed of a structure with good moisture permeability, and for the interior surface, a variable vapor retarder paper should be applied in consideration of the reverse condensation phenomenon in summer. Second, in terms of performance for hygrothermal, applications of external insulation plaster finish to the exterior wall or of ventilation method using a rafter vent on the roof should be avoided. Third, a rain screen method with a ventilation layer should be applied to the exterior wall, and a method of constructing ventilation layer separated from the insulation layer with a vapor retarder paper should be applied to the roof. Fourth, the application of insulation materials having capillary action, such as wood fiber insulation board or cellulose insulation board, contributes to more stable performance for hygrothermal.