Inorganic Insulation Materials Research Articles

Binary-Network structured PI@SiO2 nanofibrous composite aerogels with temperature invariant superelasticity for thermal insulation

The extreme temperatures encountered in aerospace pose formidable challenges to the performance of elastic materials in spacecraft and related apparatus. Traditional organic insulation materials face hindrance due to inadequate fire resistance, while inorganic insulation materials are often brittle. Herein, we designed binary-network composite aerogels with dual-crosslinked PI nanofibers as the scaffold and uniformly distributed silica nanoparticles within the anisotropic aerogel matrix. Owing to the dual-crosslinked PI nanofiber network, the resulting PI@SiO2 aerogel can withstand 1000 cycles of radial fatigue testing under 50 % compressive or buckling strains, maintaining structural stability across a wide angular frequency range of 0.1–100 rad/s. DMA testing shows that PI@SiO2 aerogel can endure 100,000 fatigue cycles from 25 to 300 °C, with storage modulus and loss modulus, and damping ratio, indicating robust long-term performance over a wide temperature spectrum. Even with liquid nitrogen (−196 °C) and butane torch flames (1100 °C), PI@SiO2 aerogel preserves its superelasticity through repeated compressions. Moreover, the composite aerogel exhibits excellent thermal insulation, with low thermal conductivity (27.2 mW m−1 K−1), and reachs the top flame-retardant level (UL94-V0). This work not only establishes a novel pathway for constructing polymer-based materials with temperature-invariant superelasticity but also holds great promise for extensive applications in ongoing and near-future aerospace exploration.

High throughput synthesis of SiO2 microspheres enhancing dielectric properties of quartz fibers insulation composites for high temperature resistant communication cable

The development of the digital society has led to an urgent demand for high-temperature-resistant, low-dielectric cable insulation materials. In order to meet the stable high temperature service performance, it is necessary to use inorganic materials instead of the traditional organic insulating materials as the cable insulation layer. Silicon dioxide (SiO2) as a widely used inorganic dielectric material has great potential for application, and quartz fiber is another wave-transparent material with good dielectric properties. The combination of SiO2 and quartz fiber can provide a feasible path for pure inorganic composite insulation materials. In this work, the high-throughput (>50 g) synthesis of SiO2 was investigated to explore the factors affecting the dielectric properties. The effects of different quartz fiber composite amounts and sintering temperatures on the dielectric properties of the composites were investigated by testing the dielectric properties of the composite powders after pressing. The composite powders doped with 20 wt% quartz fibers at 600 °C sintering temperature were found to have better dielectric properties with dielectric constant of 2.48 and dielectric loss of 0.0109 at 20 M Hz. Furthermore, the composite powders were filled into the cables and measured for electrical properties by a network analyzer. And dielectric properties of the cables preliminarily meet the performance requirements for the applications of high temperature (900 °C) radio frequency (RF) communication cables with dielectric constant of 1.731 and insertion loss of 2.02 dB at 18 G Hz. Therefore, this inorganic composite material can be used as the insulation layer for RF high-temperature-resistant communication cables for aerospace, nuclear power plants and energy fields.

Numerical Simulation Verification of the Application of Inorganic Thermal Insulation Materials to the Surrounding Rock of Roadways

Insulation materials provide a new solution for heat dissipation control in high-temperature mine enclosures. In this paper, ANSYS Fluent was selected to conduct a numerical simulation study on the heat transfer after inorganic insulation materials were laid on the surface of the mine tunnel surrounding rock. The results show that the influence of the tunnel wind flow on the temperature of the surrounding rock is related to the support material laid, and the temperature of the surrounding rock wall after laying inorganic insulation material is about 4°C lower than that of ordinary concrete support. The temperature difference of the surrounding rock wall at the entrance of the tunnel is about 4.6°C, and that of the surrounding rock wall at the exit is about 2.8°C. The comparative analysis verifies that the insulation material positively affects the heat dissipation control of the high-temperature shaft and the surrounding rock of the roadway.

RECOVERY OF PHENOL-FORMALDEHYDE SOLID WASTE FROM THE PRODUCTION OF INORGANIC THERMAL INSULATING MATERIALS

The production of inorganic thermal insulation materials with a fibrous structure, consisting of a fibrous skeleton and air pores, generates phenol-formaldehyde solid waste. Formaldehyde resin is used to crosslink, or glue, fibers together, so that most of the phenol and formaldehyde released after evaporation is found in wastewater, while the remaining part is generated as solid waste. The paper characterizes solid waste using the following chemical analyses: UV-VIS spectrophotometry, atomic absorption spectrophotometry, and gas chromatography. This is done with the aim to provide a more detailed consideration of the pollution potential. Based on the conducted research, it can be concluded that the drainage water according to the criteria for underground water contains increased amounts of copper, cadmium, lead, chromium, cobalt, nickel and phenol. At the same time, the concentrations of copper, cadmium, nickel and phenol also exceed the values, which is a condition that requires more detailed investigations. The concentration of phenol is getting close to the threshold value (0.050 mg/dm3), according to which measures are recommended. The paper proposes an eco-technical solution for waste stabilization through supercritical aqueous oxidation of phenol-formaldehyde and metal waste.

Quantitative integration of fire risk with life cycle analysis of building: The case of thermal insulation

Given the ever-growing importance of environmental sustainability, greater attention has been paid to the energy consumption of buildings. A significant share of such consumption is due to the thermal regulation of buildings’ interior spaces. Thermal insulation is highly effective in reducing these energy needs. Consequently, national policies have been introduced or revised to increase the minimum insulation requirements. Besides, a large share of thermal insulation materials is currently plastic-based. These materials were found to have increased the severity of fire consequences in a few recent major fires. Instead, inorganic fibrous insulation materials, especially those almost incombustible, have a lower impact on fire development but also lower thermal insulation performances. The optimization problem, with fire safety on one side and energy performances on the other, has been the subject of recent research. Nonetheless, due to the numerous uncertainties, such optimization is usually discussed only qualitatively. Conversely, in this work, full probabilistic methods and damage-to-impact conversion are applied to fire risk assessment and found to be a reliable strategy for a quantitative approach. Thus, a quantitative integration of fire risk-based environmental impact of thermal insulation, applied to a general case study, is presented. Damage-to-impact conversion is realized by using embodied carbon values and fire fragility functions. This application also accounts for direct greenhouse gas emissions from combustion. The final results show that fire consequences are comparable with the superior thermal performance effects in the environmental balance between plastic-based and inorganic fibrous insulation materials.

Assessment of acute and chronic ecotoxicological effects of aqueous eluates of stone wool insulation materials

BackgroundStone wool is an inorganic mineral insulation material increasingly used to reduce the climate impact of buildings. The acute and chronic ecotoxicological potential of stone wool eluates have been studied in a battery of standardized laboratory ecotoxicological tests. The experiments were conducted with stone wool test materials in fibrous and milled form, with and without the presence of organic binder. For the preparation of eluates, the OECD protocol on the transformation/dissolution of metals and metal compounds was applied. The resulting eluates were used in acute tests, i.e., bioluminescence test with Aliivibrio fischeri (DIN EN ISO 11348-1:2009), algae growth test with Desmodesmus subspicatus (OECD No. 201) and immobilization test with Daphnia magna (OECD No. 202), as well as chronic tests, i.e., the Daphnia magna reproduction test (OECD No. 211) and the nematode growth and reproduction test with Caenorhabditis elegans (ISO 10872:2010).ResultsWhile no acute or chronic ecotoxicological effects of the eluates were observed for fibrous stone wool material, the milled test materials showed some chronic effects on aquatic invertebrates. Depending on the test materials and concentrations of milled stone wool used in the eluate preparation, these chronic effects included significant stimulation or inhibition of daphnid reproduction and nematode growth. The chemical analysis conducted in parallel to the ecotoxicological assessment indicated no leaching of organic substances from the applied binder or mineral oils and no formation of nanoparticles by the milling of stone wool. Furthermore, ICP-MS and ICP-OES analysis of eighteen elements revealed that only aluminum and nickel could be quantified in the eluates, at concentrations of approximately 750 µg/L and 7 µg/L, respectively.ConclusionsBased on the present ecotoxicological assessment, eluates from stone wool fibers cannot be considered as chemically hazardous to the aquatic environment. However, additional investigations of the ecotoxicological potential of the milled material and the environmental exposure of stone wool products are necessary for a complete evaluation of potentially negative effects of stone wool insulation materials.

Innovative Inorganic Insulation Materials (Mineral Slag Based Geopolymers)

Innovative Inorganic Insulation Materials (Mineral Slag Based Geopolymers)

Waste liquid-added regeneration activator to enhance the pore structure and compressive strength of geopolymer-foam-fiber: A sustainable strategy of kenaf fiber pretreatment and reuse

Developing good pore structure, high-strength inorganic insulation materials derived from fiber-reinforced foaming geopolymer, is desirable for several applications. In this paper, a low-cost, eco-friendly, and high-efficiency method was proposed for processing alkali-treated kenaf fibers (TKF) and metakaolin geopolymer into lightweight yet strong bulk structure geopolymer-foam-fiber (GFF). The composites were produced using H2O2 as foaming agent. The waste liquid of TKF and activator (NaOH and Na2SiO3) were mixed and considered as the regenerating activator. Disordered TKF and regenerating activator with higher viscosity play a crucial role in the mechanical and pore structure of the composites. The results showed that when the foaming agent content increased, the compressive strength of composites decreased. The record-high compressive strength of geopolymer-foam (GF) increased by 1.1–2.1 times and 1.2–2.7 times for ambient temperature and 50 ℃, respectively. GFF with homogeneous pore distribution and high porosity were successfully fabricated by introducing TKF. Therefore, the thermal conductivity and compressive strength were in the ranges of 0.118–0.248 W/(m·k) (comparable to GF) and 1.6–19.9 MPa (1.1–2.6 times increase compared with GF), respectively. This low-cost and no-waste production of geopolymer foam material can enhance the utilization of agricultural waste and the development of inorganic insulation materials.

Pyrolysis of hybrid polyurethane inorganic thermal insulation: thermogravimetric analysis and FTIR spectra

Purpose. The purpose of this work is to study the process of thermal decomposition (pyrolysis) of two samples of a hybrid organic-inorganic (OIH) heat-insulating material based on data obtained by thermogravimetric analysis and IR-Fourier spectrometry. The goal set predetermined the following research tasks: to find out the basic chemical structure of the OIH samples (by functional groups), to study the order of processes in materials when heated in nitrogen, to calculate the activation energy, the pre-exponential factor, to determine the pyrolysis mechanism. Methods. The methods of thermogravimetric analysis and IR-Fourier spectrometry were used in the work. Samples for spectrometric analysis were prepared in the process of thermogravimetric tests using the “freezing” experiment method. Results and discussion. The paper studies the structural features of two samples of hybrid polyurethane inorganic (OIH) thermal insulation material and traces the physicochemical processes that occur when they are heated under dynamic conditions in a nitrogen atmosphere up to 750 °C. The multi-stage nature of the pyrolysis of the OIH material is shown. The pyrolysis of the first sample is a threestage process. For the second sample, decomposition proceeds in two stages. All stages are endothermic. This indicates the predominance of energy costs for breaking bonds between the organic and inorganic parts and other conclusions. It has been established that the pyrolysis of OIH samples at all stages is carried out according to the mechanism of nucleation and the growth of nuclei (active centers of destruction). Analysis of the IR spectra of the samples showed that both samples were prepared using Desmodur aliphatic isocyanates. Conclusions. The paper studies the chemical structure and physicochemical changes when heating the new group of materials — hybrid organic-inorganic (OIH) heat-insulating materials. The article is a continuation of a team of authors systematic study of a thermal behavior of modern types of polymer thermal insulation.

Preparation of high closed porosity foamed ceramics from coal gangue waste for thermal insulation applications

Resource utilization of industrial solid waste can be a preferred solution to waste management. This study proposes a new strategy to prepare high closed porosity foamed ceramic with coal gangue waste as the major material. The chemical composition and crystalline phase of the starting material, formation mechanism and the effects of sintering process parameters on the pore structure and properties of the samples are discussed. The results show that the density, compressive strength, and true porosity of the foamed ceramic are 0.22 g/cm3, 1.51 MPa, 91.38%, respectively, at the optimum sintering temperature and time of 1200 °C and 30 min. The high closed porosity of 83.95% compared to conventional foamed ceramics is a very favorable factor for the reduction of thermal conductivity and water absorption, resulting in a low of 0.11 W/(m·K) and 0.68%, respectively, which can be used as a cost-effective inorganic thermal insulation material in the building industry.

Using Fumed Silica to Develop Thermal Insulation Cement for Medium-Low Temperature Geothermal Wells.

During geothermal energy development, the bottom high-temperature fluid continuously exchanges heat with the upper low-temperature wellbore and the stratum during its rising process. Thermal insulation cement (TIC) can increase the outlet temperature, thus effectively reducing the heat loss of the geothermal fluid and improving energy efficiency. In this study, vitrified microbubbles (VMB) were screened out by conducting an orthogonal test of compressive strength (CS) and thermal conductivity (TC) on three inorganic thermal insulation materials (VMB, expanded perlite (EP), and fly-ash cenosphere (FAC)). Fumed silica (FS) was introduced into the cement with VMBs, as its significant decreasing effect on the TC. Moreover, a cement reinforcing agent (RA) and calcium hydroxide [CH] were added to further improve the CS of TIC at 90 °C. The fresh properties, CS, TC, hydration products, pore-size distribution, and the microstructure of the cement were investigated. As a result, a TIC with a TC of 0.1905 W/(m·K) and CS of 5.85 MPa was developed. The main conclusions are as follows: (1) Increasing the mass fraction of the thermal insulation material (TIM) is an effective method to reduce TC. (2) The CH content was reduced, but the C–S–H gel increased as FS content increased due to the pozzolanic reaction of the FS. (3) As the C–S–H gel is the main product of both the hydration and pozzolanic reactions, the matrix of the cement containing 60% FS and VMBs was mainly composed of gel. (4) The 10% RA improved the cement fluidity and increased the CS of TIC from 3.5 MPa to 5.85 MPa by promoting hydration.

Facile preparation of nano-SiO2 composites with excellent high-temperature thermal insulation performance

Inorganic thermal insulation materials can greatly reduce heat loss from high-temperature equipment, thereby supporting energy-saving technologies. Among these nano-SiO2 composites have promising application potential, which is limited by their existing preparation methods. This study aims to develop a low-cost high-performance thermal insulator. Nano-SiO2 composites were prepared by the wet impregnation of glass fibre felt with nano-SiO2 aqueous slurry and ambient pressure drying. The density of the composite linearly increased from 0.17 to 0.24 g/cm3 when the solid content of the slurry was increased from 5% to 15%. As the density of the composite increased, the thermal conductivity at 300–700 °C decreased. The introduction of SiC to the composites significantly improved their thermal insulation performance. The composite with SiC exhibited a thermal conductivity of 0.1334 W/(m·K) at 700 °C, which is better than its commercial counterpart of SiO2 aerogel felt. The rear surface temperatures of the composites at 700 °C with different pressures of 0.01–0.1 MPa were investigated to comprehensively understand the thermal insulation performances. Overall, a facile, efficient, safe, and eco-friendly preparation for nano-SiO2 composites have good prospect in the field of industrial energy saving.

Social and Economic Analysis of Project Management for Foam Glass Production Company Establishment

Currently, much attention is paid to the development of new thermal insulation materials in the production of building materials suitable for use in industrial and residential premises. Foam glass is one of the most popular inorganic thermal insulation materials. Foam glass is considered as one of the most high-quality and durable heat-insulating materials. It has a number of strength characteristics, among which are resistance to deformation, compressive strength, and resistance to environmental influences. Foam glass products are resistant to heat and aggressive chemicals, they do not undergo a combustion process, do not form smoke and do not emit toxic combustion products, and are also resistant to low temperatures. The material is easy to process, which allows you to get products of any desired shape. In this regard, this article discusses the relevance of an enterprise establishment for the production of foam glass: they performed the review of the material properties, environmental friendliness, production methods, and technologies, and analyzed the presence of competitors in the Republic of Tatarstan. The main conclusions on scheduling and social and economic analysis of the planned production are also presented. The purpose of the work is the creation of an enterprise for the production of foam glass. To achieve this goal, it is necessary to analyze the Russian market of heat-insulating materials, research the sales market and draw up a marketing plan, develop a schedule for an enterprise establishment, calculate the economic justification for the proposed production effectiveness, analyze the risks of a project for an enterprise establishment using the sensitivity analysis method.

Developing a hollow glass microsphere/geopolymer thermal insulation composite for hot metal surface coating

Manufacturing inorganic thermal insulation materials with superior properties such as low thermal conductivity (k < 0.1 W/mK) and high mechanical properties in terms of adhesion strength is critical for energy efficiency in energy-intense industries. Geopolymer-based composites composing of hollow glass microspheres (HGMs), waste fly ash (FA), and metakaolin (MK) were successfully applied on hot (T∼300 °C) metal surfaces via spray deposition technique. The effect of Si/Al and Na/Al mole ratios and HGM loading on geopolymer composites' physical, microstructural, thermal, and adhesion strength properties were explored. The best composite composition was obtained when Si/Al mole ratio, Na/Al mole ratio, and HGM loading were 2.5, 1.0, and 10 wt %, respectively. This composition achieved an HGM/geopolymer composite material with low thermal conductivity (k ∼ 0.05 W/mK), high adhesion strength (∼5.0 MPa), and high stability under immersion in water and vibration environments (particularly exposed to water). The results showed that HGM/geopolymer composites could be used as a thermal insulation material in energy-intense industries.

A facile method to prepare high-performance thermal insulation and flame retardant materials from amine-linked porous organic polymers

Developing porous functional materials with good thermal insulation and flame retardant properties is of great importance in modern eco-friendly buildings. Herein, we report the one-step synthesis of imine chain monolithic porous phosphorus-containing organic porous polymers (PPOPs) using Schiff base polycondensation reaction and as an example of efficient thermal insulation and flame retardant. Experimental results show that the PPOPs have low thermal conductivity (0.055 W·m−1·K−1) and excellent flame retardant properties. Measurements by microcalorimetry (MCC) showed a peak heat release rate (pHRR) value was 23.9 W·g−1, which is nearly an order of magnitude lower than that of most currently reported flame retardant materials. Using PPOPs in the epoxy resin (EP) matrix, the prepared EP composites exhibited excellent flame retardant properties. Cone calorimeter (CC) tests showed that the peak heat release rate (pHRR) and peak smoke release rate (pSPR) during combustion of PPOPs/EP composites were reduced by 42.0% and 36.4%, respectively, compared with pure EP. Tensile tests showed that the addition of PPOPs improved the mechanical properties of the composites to some extent. In addition, PPOPs can be designed into different shapes for practical applications compared with those fragile inorganic insulation materials and powders that were usually non-processable. Taking these advantages into account, PPOPs have great potential for modern building applications as monolithic foams or coatings with both excellent flame retardancy and thermal insulation properties.

Study on Permanent Thermal Insulation Formwork of Mass Concrete Prepared by Different Types of Nano-modified Lightweight Aggregate

Aiming at the problems of low strength, flammability, easy falling off, and aging of traditional organic thermal insulation materials, inorganic thermal insulation materials of different types of nano-modified lightweight aggregates were prepared in this paper. The feasibility of preparing permanent thermal insulation formwork of mass concrete with nano-modified lightweight aggregate was studied through experiments and calculation analysis of mechanical, durability, and thermal properties. The results show that the water absorption of shale ceramsite modified by nano-permeable hydrophobic agent is reduced to 1.21%, and the water absorption rate of inorganic precast hollow aggregate produced by nano-silica powder is lower, which is 0.79%. Inorganic precast hollow aggregate concrete, modified shale ceramsite concrete, and organic foamed aggregate concrete have the characteristics of high strength, fire resistance, aging resistance and low thermal conductivity. Inorganic precast hollow aggregate concrete and modified shale ceramsite concrete have excellent impermeability and frost resistance. Organic foamed aggregate concrete has the lowest thermal conductivity and good thermal insulation effect and its durability can be improved by surface protection technology. According to the principle of equivalent surface heat release coefficient, it is feasible to use lightweight aggregate precast formwork as permanent insulation formwork of mass concrete with thickness between 50 and 100 cm. The permanent thermal insulation formwork of nano-modified lightweight aggregate concrete can also be used as the formwork for concrete construction to realize the temperature control measures of tracking thermal insulation and slow cooling of mass concrete, reduce the risk of cracking, and improve the construction efficiency.

Hysteretic load behavior of pre‐casted reinforced concrete shear wall systems with high thermal resistance capability

ABSTRACTIt is essential to determine the thermal conductivity and earthquake performances by developing earthquake‐resistant building systems that have high thermal insulation properties that will be economical for people considering the need for energy deficit and low‐cost earthquake‐resistant residences in the world. This study aims to evaluate the seismic performance of pre‐casted reinforced concrete shear wall systems with double layer high thermal resistance capability and compare to standard monolithic reinforced concrete shear wall systems with non‐high thermal resistance capability. The coating material used for thermal insulation was developed as an inorganic, economical, easily applicable, high‐fire resistance capable and not to cause the problems observed in the currently used products. In the research, new generation methods were used to reduce the unit weight of cement binder inorganic insulation material to low levels and provide high thermal resistance features. The seismic performance tests of the new double insulation layer, pre‐casted reinforced concrete shear wall system were realized. The seismic performance of conventional reinforced concrete shear walls was compared with the developed system by testing lateral reversed cyclic loading that simulates the earthquake.

An inorganic thermal insulation material with good performance prepared from obsidian

Both obsidian and perlite belong to acid volcanic rock and have a similar structure and chemical composition, but the insulation material prepared from expanded obsidian cannot reach the performance level of that prepared from expanded perlite. To date, obsidian cannot be used in large quantities, although its resource is abundant. In order to comprehensively utilise this resource, in the present work the authors developed a new type of lightweight thermal insulation material by using obsidian as a main raw material which is energy-efficient and environmentally friendly. The effects of raw materials such as obsidian, sodium silicate, hydrogen peroxide and cetyltrimethylammonium bromide on physical properties including thermal conductivity, porosity, density and compressive strength were studied in detail. The optimised thermal insulation material exhibits low thermal conductivity (0.051–0.86 W m−1 K−1), low density (0.1–0.24 g/cm3) and adjustable compressive strength (0.09–1.52 MPa). Compared to other inorganic insulation materials, this new thermal insulation material is very light and has a better thermal insulation performance. Therefore, this work proposes a new energy-efficient way to prepare a promising noncombustible thermal insulation material, and also provides a way to use obsidian resources in large quantities.

Embodied energy and carbon of building insulating materials: A critical review

An extensive and updated review of 223 values about the embodied energy and carbon of building insulation materials, mainly retrieved from 156 Environmental Product Declarations, is proposed with attention to innovative and emerging insulation materials. Comparative analyses were carried out thanks to the adoption of the same functional unit (1 m 2 with a thermal resistance of 1m 2 K/W and a design life span of 50 years) to assess the consistence of reference values and the main sources of variability. The comparison suffers from many uncertainties and variance decomposition was employed to verify the main drivers of variability in the dataset elaborated. Data about traditional insulation materials show the lowest ranges of variation when reported per functional unit while the definition of reference values for innovative and unconventional insulation materials was quite difficult due to the low values found and their high variance. Traditional inorganic insulation materials exhibit competitive embodied impacts (glass wool: 16–31 MJ/FU and 0.6–1.2 kg CO 2 eq/FU; stone wool: 21–66 MJ/FU and 1.4–4.2 kg CO 2 eq/FU) if compared with fossil fuel derived (EPS: 44–78 MJ/FU and 1.9–3.5 kg CO 2 eq/FU) or many emerging super-insulating solutions (aerogel: 251–372 MJ/FU and 11.6–18.7 kg CO 2 eq/FU). Density is an important variability carrier for glass wool, stone wool, and EPS. • We got 223 values of PER, PENR, GWP of building insulation panels from 156 EPDs • The values were compared considering the same functional unit (1 m 2 with R = 1m 2 K/W). • Wide ranges of variation were obtained for some insulation materials. • The values of unconventional insulation materials show the highest uncertainty. • Density is a significant variability carrier for EPS, stone wool and glass wool.

Structure characteristics and hygrothermal performance of silica aerogel composites for building thermal insulation in humid areas

Building thermal insulation can enhance the thermal environment of buildings, thus decreasing energy consumption. Traditional inorganic insulation materials are easy to absorb moisture so that their insulation performance is reduced significantly when they are used in humid environment. It is of great significance to develop new building insulation materials with low moisture absorption and high thermal insulation. In this paper, sol-gel method and ambient pressure drying were used to prepare polyester fiber felt/silica aerogel composite thermal-insulation material. The hydrophobic properties and the microstructure of the aerogel composites were characterized. Moreover, the water-vapor transmission rate and the moisture absorption rate of the aerogel composites and the fiber felt in various humidity conditions were measured. Transient thermal plane method was applied to the measurement of the thermal conductivity. The thermal conductivity and moisture absorptivity of the polyester fiber felt increased significantly with the increase of ambient humidity. After being composited with silica aerogel, both moisture absorptivity and thermal conductivity decreased significantly and kept small value even in high humidity. The moisture absorption rate of the composites is approximately 1%, and the thermal conductivity is 0.0176–0.0187 W·m−1·K−1. Therefore, the prepared fiber felt/silica aerogel composites could be widely used for building insulation even in humid areas.