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Liner materials have extensive applications in automobile industry, packaging, and aeronautics. One of the specific uses of such materials is in thermal barrier, coating rockets, missile, and other systems used in space and defense. Each liner material exhibits different properties according to their chemical structure and composition. In this study, accelerated thermal aging of the liner material, silicone‐hollow glass microsphere composite (SHGC) has been studied along with the determination of its life span. The effect of such aging on the thermal properties of SHGC has been studied using thermogravimetry. Activation energy of the process has been determined to be in the range of 45–55 KJmol−1. The results have been compared with already reported silicon polymers. Shelf‐life of SHGC composite has also been determined using Arrhenius model. Stochastic model has been applied to determine the lower and upper limits of shelf‐life. Shelf‐life of SHGC is found to be 24 years with 28 and 18 years of upper and lower error limits. [ABSTRACT FROM AUTHOR]

Context: Traditional conductive adhesives based on epoxy resin system often encounter problems such as high brittleness and low heat resistance. Therefore, it is particularly important to improve the thermal and mechanical properties of the conductive adhesive. In this study, the effects of SWCNT-Ag and SWCNT fillers on the thermal properties of DGEBA/DETA/Ag conductive adhesive system were studied by using molecular dynamics to construct different cross-linking models. The final results show that the addition of SWCNT and SWCNT-Ag can significantly improve the thermal properties of the conductive adhesive. However, the nanosilver particles on the surface of SWCNT-Ag act as a bridge for the connection between SWCNT and Ag in the conductive adhesive. Therefore, SWCNT-Ag has a more positive impact on the thermal properties of DGEBA/DETA/Ag conductive adhesive system. Methods: In this paper, the influence of SWCNT-Ag on the thermal properties of traditional DGEBA/DETA/Ag conductive adhesive system was studied by using Materials Studio software. The volume shrinkage, glass transition temperature, thermal expansion coefficient, and thermal conductivity of the material were calculated based on COMPASS force field. The thermal conductivity is calculated by using reverse non-equilibrium molecular dynamics method. Finally, it is found that SWCNT-Ag has a positive effect on the thermal properties of the conductive adhesive system by comparing several groups of calculation data. [ABSTRACT FROM AUTHOR]

A series of halloysite nanotube‐silica (HNTs‐SiO2) nanocomposite fillers were prepared by in‐situ assembly, and a reinforced SiO2/SR composite was obtained by filling them into silicone rubber (SR). The morphology and structural characterization of HNTs‐SiO2 and HNTs‐SiO2/SR and the properties of the HNTs‐SiO2/SR were studied. As a result, the small particle size SiO2 was firmly anchored onto the HNTs surface, and the obtained HNTs‐SiO2 nanofillers were uniformly dispersed in SR. At a 30 phr fixed filler loading, the weakest filler network and the best filler dispersion were obtained when HNTs content in HNTs‐SiO2 was 5%. This resulted in a maximum tensile strength obtained of 6.2 MPa, 1.55 times that of SiO2/SR with the same filler loading, and a maximum elongation at break of 418%, 1.67 times that of the SiO2/SR with the same filler loading, and at the same time the tearing strength and hardness are also improved. Furthermore, the silicone rubber also showed improved thermal stability, with an initial degradation temperature increase of 30°C under a nitrogen atmosphere. Highlights: HNTs–SiO2 nanocomposites were successfully prepared by the self‐assembly method and used as fillers in SR as a new type of reinforcing material.The 1D HNTs act as a barrier to prevent SiO2 aggregation and improved fillers dispersion.The elongation at break and tensile strength of 5% HNTs‐SiO2/SR are 67% and 55% higher than those of SiO2/SR, respectively.The silicone rubber also showed improved thermal stability. [ABSTRACT FROM AUTHOR]

In-situ methods are highly desirable for the development of segregated conductive composites. We demonstrate a benign and simple method for developing segregated conductive poly (methyl methacrylate)/reduced graphene oxide composites by incorporating two-step in-situ reduction of graphene oxide (GO) with poly(methyl methacrylate) (PMMA) microspheres. First, a one-pot method is demonstrated that involves the synthesis of positively charged PMMA latex followed by in-situ hydrazine reduction of negatively charged GO. In the second step, thermal reduction at 150 °C is used to increase the reduction level of GO. As a result of two-step reduction of GO, the obtained composite exhibits good correlation between their structural, morphological, thermal, and electrical properties. Compared to PMMA matrix, 4 wt % composites formed after in-situ reduction using hydrazine (PMMA-rGO-H) and two-step method (PMMA-rGO-HT) exhibit approximately 108 and 109 fold increases in electrical conductivity, respectively. Further, the percolation threshold for conduction is 1 wt%, indicating the generation of segregated conductive networks. [ABSTRACT FROM AUTHOR]

Ceramic fibers are an important thermal insulation material that are not only widely used in extreme conditions, but also play an important role in energy conservation and energy efficiency for sustainable development. However, the practical application of conventional ceramic fibers has a high thermal conductivity in high-temperature environments, which hinders their widespread application. Here, a novel lamellar structured porous SiTiOC/C composite ceramic materials was designed and prepared with excellent thermal insulating properties. The unique microstructure endowed the porous SiTiOC/C composite ceramic materials with a high IR refractive index (93.81%) and an ultra-low thermal conductivity (0.0562 W·m−1 K−1 at 600 ℃). In addition, the porous SiTiOC/C composite ceramic materials not only exhibited excellent mechanical properties (4.46 MPa at 800 ℃), but also demonstrated impressive oxidation resistance and thermal stability. In summary, the proposed porous SiTiOC/C composite ceramic materials provide a reference for the development of high-temperature insulation with good mechanical properties. [ABSTRACT FROM AUTHOR]

This study investigates the effect of positive temperature coefficient (PTC) fillers, i.e., barium strontium titanate (BST‐60) and nano hexagonal boron nitride (h‐BN) fillers, on thermal and dielectric insulation properties of epoxy (EP). The electrical resistivity, DC breakdown strength, space charge, thermal conductivity, thermogravimetric analysis, and glass transition temperature (Tg) of EP composites were measured. Results indicate that, below curie temperature, the EP composites containing 0.5 and 1 wt% of BST and 5 wt% of h‐BN have superior electrical resistivity, breakdown strength, and thermal conductivity. However, above curie temperature, the EP composites containing 2 and 2.5 wt% of BST and 5 wt% of h‐BN have superior insulation properties than the pure EP and other composites. While the thermal properties of EP improve with an increase in h‐BN loading to 10 wt%, its dielectric properties are slightly compromised due to the presence of tiny defects in the composite material. It is hypothesized that the BST‐60 suppresses the negative temperature coefficient effect (NTC) of EP by regulating the electrical resistivity above the curie point, whereas nano h‐BN enhances the thermal conductivity of EP by constructing a heat dissipation path. The proposed mechanism for charge dynamics along with heat conduction‐dissipation explains the fillers' behavior at different temperatures. Highlights: Analysis of epoxy composites with polydopamine‐modified BST and h‐BN fillers.PTC fillers are used to mitigate the negative temperature effect of epoxy.Optimal fillers wt% improves dielectric and thermal properties.This study shows that optimized epoxy composites can be used for packaging. [ABSTRACT FROM AUTHOR]

In recent years, the packaging industry has utilized electronic packaging materials with epoxy resin (EP) and high‐performance fillers, exhibiting superior mechanical properties and thermal conductivity. Spherical silica micro‐powder (SSP) is a critical thermal conductive filler but faces challenges due to its inorganic nature. Surface modification is essential to improve SSP's compatibility and dispersion in organic matrices for effective use in EP‐based composites. In this paper, the effects of the following four modification methods on SSP/EP composites were studied: (1) the processes include co‐modification with dimethyldimethoxysilane (DMDMS) and trimethylethoxysilane (MTES), (2) modification with NaOH, (3) co‐modification with DMDMS and MTES in an alkaline environment after NaOH modification, and (4) co‐modification with methyltrimethoxysilane (MTMS) and propyltrimethoxysilane (PTMOS). Through comprehensive characterization and evaluation, it is evident that modification schemes 1, 3, and 4 significantly enhance SSP's hydrophobicity, dispersibility, and compatibility with EP. This led to the improvement of thermal conductivity and stability of the composite, and modification scheme 4 showed the highest enhancement, with a 42.6% increase in thermal conductivity. Moreover, the mechanical properties of modified composite materials, such as bending strength, impact resistance, and tensile strength, surpass those of unmodified SSP/EP composite materials. The study provides valuable insights for reducing manufacturing costs and enhancing productivity in the electronic packaging sector. [ABSTRACT FROM AUTHOR]

Despite of excellent thermal properties and high sputtering resistance, pure tungsten cannot fully satisfy the requirements for plasma facing materials in future high-duty cycle nuclear fusion reactions due to the coupled extreme environments, including the high thermal loads, plasma exposure, and radiation damage. Here, we demonstrated that tungsten-based composite materials fabricated using spark-plasma sintering (SPS) present promising solutions to these challenges. Through the examination of two model systems, i.e., tungsten-zirconium composite for producing porous tungsten near the surface and dispersoid-strengthened tungsten, we discussed both the strengths and limitations of the SPS-fabricated materials. Our findings point towards the need for future studies aimed at optimizing the SPS process to achieve desired microstructures and effective control of oxygen impurities in the tungsten-based composite materials. [ABSTRACT FROM AUTHOR]

The Sidr Leaves Powder (SLP) is full of natural renewable, and cost-free energy resources with excellent heat resistant properties. Mixing natural fillers in conjunction with unsaturated polyester increases the mechanical and thermal features of composites, which eliminates or reduces the need for additional binders. This study probes the outcomes of supplementing Sidr Leaves Powder at different filler concentrations on the mechanical properties (durability, compression, and impact) as well as thermal conductivity accompanied by FTIR spectroscopy characterization of unsaturated polyester composites. Samples were made using hand-lay molding procedures. The consequences reveal that the maximal impact resistance is (2.52kJ/m²), the highest hardness (72.4 N/mm²), and the highest compressive strength about (48.7 MPa). Moreover, the thermal conductivity's value drops to (0.101 W/m.℃). on 25% volumetric fraction. With FTIR spectra, the evidence of alteration in the chemical content and molecular structure of nanocomposites with varying filler content emerged, making the analysis of the composite material properties possible. These outcomes indicate the prospective usefulness of these composites in such fields as furniture manufacturing, especially in case of a couch due to their super properties. [ABSTRACT FROM AUTHOR]

This study aims to develop sustainable, renewable and biodegradable biocomposite films from environmentally friendly materials. For this purpose, completely biodegradable polymer composites were prepared by mixing polylactic acid (PLA) with a new source, quince peel (QP), by solvent casting method, and their structural, mechanical and thermal properties were examined. The tensile strengths of the composites prepared using QP in proportions varying between 5% (P5Q) and 30% (P30Q) by weight vary between 21.13 ± 0.80 and 12.01 ± 0.10 MPa, and their elongations at break vary between 11.33 ± 0.38 and 4.08 ± 1.06 %. As the QP contribution increased, the tensile strength and breaking elongation of these composites generally decreased, while the elastic modulus also increased. Among these composites, whose elastic modulus varies between 1040.00 ± 140.01 and 811.33 ± 13.31 MPa, it was determined that the elastic modulus (1040.00 ± 140.01 MPa) of the 20% QP added composite (P20Q) was higher than the others. When the thermal analysis of PLA/QP films were examined, it was observed that the glass transition temperatures (Tg) were between 58.54 and 51.45°C and the melting temperatures (Tm) were between 167.71 and 164.28°C, and these temperatures generally decreased with increasing QP doping. When the T50 values, which represent the temperature at which 50% of the composite materials decompose, were examined, it was found that the QP-added ones were higher than the pure composites. While this value was 317.96°C in pure PLA composite, T50 values varied between 327.92 and 340.80°C depending on the varying QP ratios. According to the XRD results performed to evaluate the crystalline properties of PLA composites containing quince bark, the crystallinity of pure PLA was determined as 19.5% and the crystallinity of composites containing 5, 10, 20 and 30 wt % QP additives was determined as 19.3, 18.3, 16.4 and 14.6%, respectively. [ABSTRACT FROM AUTHOR]

In the global context of environmental awareness, the present research proposes a sustainable alternative to the widely used petroleum-based epoxy coatings. Epoxidized corn oil (ECO) was tested as potential matrix for advanced nanocomposite coating materials reinforced with 0.25 to 1 wt.% single-walled carbon nanotubes (SW) with carboxyl and amide functionalities. The elemental composition of the epoxy networks was monitored by XPS, showing the increase of O/C ratio to 0.387 when carboxyl-functionalized SW are added. To achieve sustainable composite materials, citric acid was used as curing agent, as a substitute for conventional counterparts. The influence of both surface functional groups and concentration of SW was evaluated through structural and thermo-mechanical analysis. The progressive increase of the DSC enthalpy for SW formulated systems indicates a possible pattern for specific interactions within the bio-based epoxy translated by adjusted activation energy. For 1% neat SW addition, the Ea values decreased to 46 kJ/mol in comparison with 53 kJ/mol calculated for neat epoxy. Furthermore, the -COOH groups from SW nanostructures exerted a strong influence over the mechanical performance of bio-epoxy networks, improving the crosslinking density with ~ 60% and twofold the storage modulus value. Accordingly, by gradual addition of SW-COOH filler within the ECO-based formulations, a very consistent behaviour in seawater was noted, with a 28% decreased value for the absorption degree. [ABSTRACT FROM AUTHOR]

Using a hand lay-up approach, both orange peel and coconut coir fibres are used in particulate form with an epoxy matrix to create partly green biodegradable composites. The findings indicate great opportunities for employing these natural fibres. The thermal conductivity of orange peel and coconut-coir epoxy composites was measured experimentally for various volume fractions of particulate fibres. The experimental findings show that as fibre concentration increases, thermal conductivity decreases. Experimental data are compared to theoretical models to determine the change in thermal conductivity with fibre amount fraction.There was a clear correlation between the hypotheses and the actual results. Regression analysis using Python programming is also done for the prediction of the thermal properties of particulate orange peel and coconut-coir fibre composites. It is observed that coir fibre composites outperformed the orange peel, indicating that the coir fibre composite is a proper thermal insulator that can be used in many industries, like the automotive industry, buildings, and steam pipes, to reduce heat transfer and thereby save a lot of energy. [ABSTRACT FROM AUTHOR]

The purpose of this research is to produce composites of epoxy resin and calcium carbonate (EP/CaCO3) and investigate how treating the CaCO3 filler with stearic acid and gamma radiation affects the properties of the epoxy composites, enhancing their suitability for a range of applications. The CaCO3 powder was subjected to stearic acid treatment and later exposed to γ-radiation at various doses namely (10, 20 and 30 kGy), Different weight percentages of untreated and treated CaCO3 powder were added to epoxy resin (EP) to create EP/CaCO3 composites loaded with varying amounts of CaCO3 filler (5 %, 10 %, 20 %, 30 %, and 40 %). The influence of both stearic acid treatment and different doses of gamma radiation on CaCO3 was investigated. The composites were subjected to characterization of various properties including mechanical (splitting tensile strength, impact strength), thermal (TGA and dimensional thermal analysis) as well as morphological SEM examination. The analysis' findings demonstrated that the stearic acid monolayer functions as a coupling agent in the EP matrix and can coat CaCO3 particles efficiently. The modification of CaCO3 by stearic acid and exposure to 30 kGy of gamma radiation shows a notable improvement in thermal stability and mechanical qualities for the epoxy composites loaded with various CaCO3 concentrations. [ABSTRACT FROM AUTHOR]

In this paper, polysulfonamide‐based composite materials (SCF/PSAf composite) reinforced by the short carbon fiber were prepared. The mechanical properties and thermal stability of SCF/PSAf composite were characterized experimentally and compared with those of polysulfonamide‐based single‐polymer composites (PSA SPCs). Results showed that SCF/PSAf composites exhibit higher thermal stability due to the excellent thermal stability of SCFs. Furthermore, the additional short carbon fibers also considerably enhance the flexure strength of PSA SPCs due to the strong interfacial bonding between SCF and PSAf. The properties and understanding of SCF/PSAf composite obtained in this work can benefit further applications of this novel composite material. Highlights: SCF/PSAf composites are prepared by hot compression, and the adhesion between the PSA matrix and SCF is good.The flexural strength of the SCF/PSAf composite is about 2.5 times higher than that of PSA SPCs.The storage modulus of SCF/PSAf composites is about 3.5 times higher than that of PSA SPCs.The addition of short carbon fibers helps to improve the thermal properties of SCF/PSAf composites.SCF/PSAf composite has a stronger ability to resist deformation and a higher operating temperature than the PSA SPCs do. [ABSTRACT FROM AUTHOR]

The main objective of this study was to investigate the mechanical and thermal properties of bamboo, as well as interlaminar hybrid composites reinforced with both bamboo and synthetic fibres in an epoxy matrix. Bamboo and glass, aramid, and carbon bidirectional fabrics were used with a bi-component epoxy matrix to fabricate the composite materials using the vacuum bagging process. The synthetic fabrics were placed on the outer layers, while the bamboo fabrics were used as the core of the hybrid composites. The developed composites were characterized and compared in terms of morphological, physical, and mechanical properties. Further, thermogravimetric (TGA) analysis was used to measure and compare the degradation temperature of the composites studied. Finally, a Scanning Electron Microscopy (SEM) analysis was performed in order to examine the fracture surfaces of the specimens tested. It was found that the fibre hybridization technique significantly improved the general mechanical properties. TGA analysis showed an increase in the thermal stability of the composites obtained by incorporating the synthetic fibres, confirming the effect of hybridization and efficient fibre matrix interfacial adhesion. The results from this work showed that the use of synthetic fibre reinforcements can help to significantly improve the mechanical and thermal properties of bamboo fibre-reinforced composites. [ABSTRACT FROM AUTHOR]

With the development of microelectronics products with high density and high power, it is urgent to improve the electrical and thermal conductivity of electronic paste to achieve the new requirements of packaging materials. In this work, a new synthesis method of Ag-MWCNTs was designed: Firstly, carboxylated MWCNTs and stannous chloride were used as raw materials to prepare high-loading-rate Sn-MWCNT composite material to ensure the high loading rate of metal on the MWCNT surface. Then, Ag-MWCNT composite material was prepared by the chemical displacement method to solve the problem of the low loading rate of silver nanoparticles on the MWCNT surface. On the basis of this innovation, we analyzed and compared the electrical, thermal, and mechanical properties of Ag-MWCNT composite electronic paste. Compared with the electronic paste without adding Ag-MWCNTs, the resistivity was reduced by 77%, the thermal conductivity was increased by 66%, and the shear strength was increased by 15%. Therefore, the addition of Ag-MWCNTs effectively improves the electrical, thermal, and mechanical properties of the paste, making it a promising and competitive choice for new packaging materials in the future. [ABSTRACT FROM AUTHOR]

This article explored the influence of curtain climber fiber and Biochar derived from Kigelia pinnata fruit fiber on a polyepoxide‐based composite material's thermal, mechanical, dielectric, and mechanical properties. Before commencing the composite production process, the surface of the curtain climber fiber underwent treatment with a solution consisting of 5% silane to enhance the bonding between the fiber and the matrix. The hand layup method and compression molding were used to produce the composite panels and tested according to the appropriate standards set by the ASTM. According to these findings, the mechanical properties of the composites were enhanced by adding 30% curtain climber fiber and 5% biochar. The load distribution on the fiber was consistent throughout. The composite's highest strength (EFB3) was 183 MPa, its modulus was 5.9 GPa, and its flexural strength and modulus were 216 MPa and 6.1 GPa, respectively. The impact intensity is 8 J, and the hardness value is 95 on the Shore D scale. In addition, the EFB3 had a maximum interlaminar shear strength of 35 MPa. According to the findings of the SEM surface analysis, the matrix molecules exhibit adhesion to the fiber, which indicates increased bonding. The thermal conductivity and dielectric properties were high for composite with higher biochar particle content. These waste biomass‐converted fruit fiber biochar and curtain climber industrial crop fiber epoxide composite materials may be utilized in a variety of sectors, including aerospace, automotive, household domestic product manufacturing, and defense sectors. Highlights: Extraction and silane treatment of curtain climber fiber.Producing biochar from waste biomass Kigelia pinnata fiber.Fabrication of polyepoxide composite.Siloxane layer improves the strength.Biochar improves the properties of composites. [ABSTRACT FROM AUTHOR]

Gypsum is a polyvalent building material, whose composition gives it interesting properties for the construction industry, but its major disadvantage is its fragility. We proposed to study the feasibility of obtaining gypsum-based composite materials using plant fibres derived from date palm waste (DPF: date palm fibres), in order to exploit a local resource, and using synthetic polyester fibres (PF: polyester fibres) for comparison. We have developed gypsum-based composites with three types of reinforcement with mass percentages of the order of (0.5% DPF), (0.5% PF) and (0.25% DPF+0.25% PF). It was found that the addition of (0.5% DPF) can increase the flexural strength by up to 29.25% and that mixing gypsum with (0.25% DPF+0.25% PF) can slightly reduce its thermal conductivity by around 13.09% and increase its flexural strength by around 45.07%. However, a decrease in the transverse compressive strength of gypsum reinforced with date palm fibres was observed for the two mixtures of (0.25% DPF+0.5% PF) and (0.5% DPF) of approximately 12.56% and 24.32% respectively. These poor results of compression are due to the poor adhesion between the date palm fibres and the gypsum matrix, as well as to the porous structure of the date palm fibres observed under the microscope. Gypsum composites incorporated by DPF can be used for thermal insulation to reduce energy consumption and as decorative materials to line a wall, create a partition or a false ceiling. [ABSTRACT FROM AUTHOR]

The treatment of waste plastics has gradually become a hot topic in the current scientific community. In response to the needs for high-impact performance R-PP-based composites, carbon fiber (CF)-reinforced polyolefin elastomer (POE)/recycled polypropylene (R-PP) composite (CF/POE/R-PP) was prepared by the mechanical blending method, and its mechanical and thermal properties were systematically studied. It was found that the CF could effectively improve the bending and notch impact strength as well as enhance the thermal stability of POE/R-PP. Furthermore, a stable and dispersed composite interface formed by the combination of maleic anhydride-grafted polypropylene (PP-g-MAH) with the surface of CF and the fusion alkyl chains in R-PP and POE further enhanced the CF's reinforcing effect. As a result, the addition of 9 wt.% CF successfully improved the heat resistance of the composite material, and the residual carbon content increased by 97.84% after sintering. The composite toughening of POE and CF effectively improved the impact strength of the composite material, with a maximum increase of over 1000%. This study ultimately resulted in a high-impact-resistant composite material. [ABSTRACT FROM AUTHOR]

Polymer‐based composites are designed to improve mechanical and thermal characteristics. This study utilized a peridynamic methodology to simulate polymethyl methacrylate/hydroxyapatite composite beams. The simulation involved the crack growth within the computational domain, and an analysis was conducted to evaluate the mechanical and thermal properties of the defected system. The outcomes derived from the peridynamic analysis revealed that an augmentation in the hydroxyapatite ratio within the samples resulted in a decrease in their mechanical and thermal efficiencies. To elucidate further, at an impact velocity of 2 mm/s, the flexural modulus increased to 3.69 GPa, the flexural strength decreased to 132.34 MPa, and the thermal conductivity converged to 0.148 W/m·K, when the hydroxyapatite ratio was at 15%. In the course of the conducted investigations, it became evident that the impact velocity significantly influences the evolutionary behavior of particles within the samples. In particular, with an increase in the impact velocity up to 5 mm/s, the thermal conductivity decreased to 0.139 W/m·K. The results of this study indicate that by modifying the hydroxyapatite ratio and impact velocity, it is possible to control the mechanical and thermal properties of the polymethyl methacrylate/hydroxyapatite composite beams. This optimization allows for their suitability in various engineering applications. [ABSTRACT FROM AUTHOR]

Lignin is an abundant and sustainable resource that exhibits numerous attractive functional properties as a reinforcing agent for benzoxazine‐based composites, due to its stiffness, thermal stability, and high carbon content. However, the low quality of lignin particles dispersions associated with the weak particles‐matrix interactions reduces the reinforcement capability. In this work, hybrid lignin/silica (NaLS/SiO2) nanoparticles were obtained from sodium lignosulfonate (NaLS) and tetraethylorthosilicate (TEOS) under basic conditions. The particles were characterized by transmission electron microscopy (TEM) confirming their spherical morphology and narrow nanometric‐size distributions. The hybrid particles were incorporated into conventional benzoxazine (BA‐a) and a difuran biobased benzoxazine (SA‐dfda) to prepare nanocomposites with different mass compositions (3, 5, and 10 wt%). Morphological, mechanical, dynamo‐mechanical, and thermal properties of the obtained composites were assessed. All the materials exhibited a homogenous filler dispersion that contributed to improve the reinforcement properties. Hybrid nanoparticles proved to be an interesting alternative as a filler in the benzoxazine matrix to prepare high‐performance thermosetting composites. [ABSTRACT FROM AUTHOR]

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This article proposes a modeling method for C/C-ZrC composite materials. According to the superposition of Gaussian random field, the original gray model is obtained, and the threshold segmentation method is used to generate the C-ZrC inclusion model. Finally, the fiber structure is added to construct the microstructure of the three-phase plain weave composite. The reconstructed inclusions can meet the randomness of the shape and have a uniform distribution. Using an algorithm based on asymptotic homogenization and finite element method, the equivalent thermal conductivity prediction of the microstructure finite element model was carried out, and the influence of component volume fraction on material thermal properties was explored. The sensitivity of model parameters was studied, including the size, mesh sensitivity, Gaussian complexity, and correlation length of the RVE model, and the optimal calculation model was selected. The results indicate that the volume fraction of the inclusion phase has a significant impact on the equivalent thermal conductivity of the material. As the volume fraction of carbon fiber and ZrC increases, the equivalent thermal conductivity tensor gradually decreases. This model can be used to explore the impact of material microstructure on the results, and numerical simulations have studied the relationship between structure and performance, providing the possibility of designing microstructure based on performance. [ABSTRACT FROM AUTHOR]

The performance of microwave devices is significantly influenced by the substrates employed. In this study, we introduce a novel microwave composite substrate material exhibiting high dielectric constant and exceptional thermal conductivity, comprising dopamine-modified boron nitride nanosheets (BNNS@PDA) and SrTiO 3 /polyolefin. With an 8 wt% BNNS@PDA filler content, the composite material achieves a high dielectric constant of 17.7 (@10 GHz) and remarkable thermal conductivity of 1.604 W/(m·K), representing enhancements of 34% and 104% compared to SrTiO 3 /polyolefin, respectively. Additionally, a low dielectric loss of 2.95 × 10−3 and minimal water absorption of 0.15% are attained. The incorporation of BNNS@PDA augments the compatibility between the ceramic particles and resin matrix, contributing to increased dielectric constant, superior density and improved mechanical properties of composite materials. As an interval within the thermal conductive pathway, the PDA coating diminishes the system's thermal conductivity. And its interplay with polymer matrix influences the resin's curing process, subtly reducing the composite's thermal stability. In summary, BNNS@PDA/SrTiO 3 /polyolefin represents a promising microwave dielectric substrate material, offering high dielectric constant and excellent thermal conductivity. [ABSTRACT FROM AUTHOR]

In order to improve the comprehensive properties of polylactic acid (PLA) and broaden the application field of PLA composites, reduced oxidized graphene (rGO) grafted caprolactone (CL) was prepared as a nanofiller, and rGO-PCL/PLA composites material were prepared by solution blending. The chemical structure, micromorphology and dispersibility of rGO-PCL were studied. The effects of rGO-PCL mass fraction on the microstructure, mechanical properties, thermal properties and hydrophilic angle of the composite were discussed. The results show that the rGO-PCL nanofiller demonstrated excellent dispersibility in the blend solution. Compared with pure PLA, when the mass fraction of rGO-PCL reaches 1%, it could be uniformly dispersed in the PLA matrix, and has excellent hydrophilicity. The tensile strength and the elongation at break increase by 19% and 180%, respectively. The thermal stability and crystallinity are significantly improved. The rGO-PCL/PLA composite holds promising potential for applications in textile fibers, 3D printing materials, packaging materials and other fields. [ABSTRACT FROM AUTHOR]

Fly ash (FA) is a kind of porous solid waste from coal-fired power plant, It is nominated as adsorption carrier for solid-liquid phase change material (PCM), While shape-stabilized composite phase change materials (SSCPCM) prepared directly has low thermal performance due to limited adsorption capacity of FA. Therefore, modification methods have become increasingly attractive, and four modification methods were investigated to improve the adsorption capacity of FA. Modification treatment experiment proved that the surface structure of FA is significantly corroded. Test analysis displays that the surface microspheres in FA have abundant particles and pores by destroying the Si–O–Si and Si–O–Al network structures. The mass ratio of Al/Si increased from 0.59 to 0.726, and the specific surface area of FA has been greatly increased. Experimental results indicate that alkali modification followed by high-temperature calcination is the desirable process for FA. For obtaining high thermal performance materials, two kinds of SSCPCM were prepared according to the mass ratio of 65:35 by vacuum adsorption while Alkali modified FA serves as carrier, binary eutectic of lauric acid-stearic acid (LA-SA) and lauric acid-myristic acid (LA-MA) serves as PCM respectively. The LA-SA/AFA-OH (NaOH alkali leaching treatment for FA) and LA-MA/AFA-OH (NaOH alkali leaching treatment for FA) could reach 54.49 J/g and 47.15 J/g and the phase transition temperature (PTT) is 37.45 °C and 32.36 °C, respectively. The SSCPCM has good thermal, chemical and morphological stability over 500 thermal cycles, while the LA-MA/AFA-OH had higher stability and less thermal performance slightly. Research finding provide a feasible process for composite modification of FA, and application scope is extended due to high thermal performance of composites. [ABSTRACT FROM AUTHOR]

The utilization of functionalized graphene oxide as nanofillers has attracted significant attention in the development of high-performance composite materials. In this study, amine-functionalized graphene oxide (AFGO) by different amines, including p-phenylenediamine- (PPD-GO) and 4, 4'-diaminodiphenyl ether (ODA-GO), respectively, was prepared and used to synthesize a series of polyimide (PI) composite membranes via in situ polymerization method. The PPD-GO/PI and ODA-GO/PI composite membranes exhibited much higher mechanical and thermal properties than that of neat PI, owing to the diverse interfacial interaction and the surface architecture behavior. Compared to neat PI, the tensile strengths were enhanced 14.6% and 14.5%, the tensile modulus were enhanced 26.9% and 23.2%, and the Tg increased by 9°C and 17.5°C of the PI composite membrane containing 0.3 wt% PPD-GO or ODA-GO, respectively. This study provides a guidance for the development of high-performance PI composite materials through the regulated interfacial structure via the moderate chain length. [ABSTRACT FROM AUTHOR]

The main objective of this work is to evaluate the mechanical and thermal strength of a recently developed composite made of Cissus quadrangularis fiber coupled with Polylacticacid (PLA) in comparison to other natural fibers. This study investigated three different fiber and PLA compositions—20%, 30%, and 40%, respectively used to produce a composite. In contrast, another composite with the same volume percentage was created using calcium hydroxide Ca(OH)2 to coat the fibers in order to alter their microcrystalline structure and enhance their mechanical properties. The composite was created using an injection molding procedure. Tests were performed to assess the improved properties. According to a preliminary study, the mechanical characteristics of PLA combined with treated Cissus quadrangularis fiber are increased when compared to PLA coupled with untreated Cissus quadrangularis fiber and neat PLA. Calcium hydroxide acted as a binding agent in fiber to enhance stress transmission in the matrix, increasing tensile and flexural modulus as well as toughness elongation. Further DSC analysis showed that the inclusion of the preceding components increased the glass transition temperature and melting temperature. The temperature at the beginning of deflection has risen as a result of showing how increasing HDT, fiber–matrix adhesion, and fiber content are related. The morphological analysis was performed on both untreated and chemical-treated fiber composites by using an optical microscope to see the interaction with the fiber matrix. [ABSTRACT FROM AUTHOR]

The research and application progress of resin-based composite materials in the field of electrical insulation has attracted considerable attention and emerged as a current research hotspot. This review comprehensively summarized the research and application progress of resin-based composite materials in the field of electrical insulation, providing detailed insights into their concept, properties, and preparation methods. In addition, a comprehensive evaluation of the electrical insulation performance, mechanical properties, and thermal properties of resin-based composite materials was presented, along with an in-depth analysis of their current application status. Despite the immense potential and development opportunities of resin-based composite materials, they also face several challenges. This review serves as a valuable reference and resource for researchers in related fields and aimed to promote further research and application development of resin-based composite materials in the field of electrical insulation. [ABSTRACT FROM AUTHOR]

In the global pursuit of using sustainable constituents for developing composite materials, the current investigation has paid particular attention to the most promising biopolymers, such as poly(lactic acid) (PLA) and bio-based poly(butylene succinate) (bio PBS). The research endeavor emphasizes a comparative assessment of short sisal fiber (SF) reinforced (10, 20, and 30 wt%) PLA and bio PBS biocomposites. The analysis and discussion have been reported for the thermal, mechanical, crystallinity, and dynamic mechanical behavior of developed composite materials. Based on mechanical properties, the optimal fiber loading for SF/PLA and SF/bio PBS biocomposites was 20 and 30 wt%, respectively. The developed composites have shown a considerable improvement in crystallinity of 17.88 and 41.13% at 20 and 30 wt% of fiber loading in SF/PLA and SF/bio PBS, respectively. The maximum storage modulus values of 14.23 GPa (20SF/PLA) and 11.74 GPa (30SF/bio PBS) were observed. The loss modulus of the SF/PLA and SF/bio PBS composites was around 74 and 89% higher than the loss modulus of the PLA and the bio PBS matrix, respectively. Overall, composites fabricated with bio PBS (SF/bio PBS) have shown better crystallinity, thermal stability, and ease of processing than SF/PLA composites. [ABSTRACT FROM AUTHOR]

The use of polylactic acid‐based composites as self‐fixing materials is a promising technology for various applications due to the shape memory effect of polylactide. In this study, hexagonal boron nitride (h‐BN) was mixed with polylactic acid (PLA) with concentrations of 0, 0.5, 1, 2, 5, and 10 wt% for subsequent film casting. The morphology, mechanical and thermal characteristics of the composite were investigated. With a high percentage of filler content, a decrease in thermal conductivity was observed. The recovery strain decreased with increasing the filler content. The amount of h‐BN had a mixed effect on the recovery stress of the composite. Thus, PLA/h‐BN composites represent a new research idea to study the influence of a heat‐conducting filler on a shape memory effect in polylactic acid. Highlights: Correlation between crystallinity, thermal and shape memory properties was describedDecrease in thermal conductivity was observed with the large percentage of fillingThe composite with 2 wt% of h‐BN exhibits optimal characteristics of SMERecovery strain decreased with the rise of filler contentAmount of h‐BN had a non‐trivial effect on the recovery stress of composite [ABSTRACT FROM AUTHOR]

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The work was aimed to study the influence of multi-walled carbon nanotubes (MWCNT) on the thermostructural properties of aluminum matrix in a wide temperature range from 30 to 600 °C. To achieve this aim, a nanomaterial with a composition of Al + 1.5% MWCNT was elaborated by sintering and rolling from aluminum and MWCNT powders. This material has to combine the ductility and lightness of aluminum with the toughness and thermal properties of MWCNT, and it can replace classical metal materials. The mechanical and structural properties of Al + 1.5% MWCNT material were studied using different techniques: differential scanning calorimetry, X-ray diffraction, thermogravimetry, Raman spectroscopy, and dilatometry. The reaction between an Al matrix and nanotubes leads to the formation of the carbides and some carbon dissolution in the matrix's crystal network. These reactions also lead to a refinement of the matrix grain and a more homogeneous distribution of the residual MWCNT. These phenomena significantly influence the structure of the matrix as well as the mass and dilatometric stability of the material. Reduction of the dilatometric coefficients of the composite material was observed in the entire temperature range of 30–600 °C, especially a significant reduction was measured for temperatures higher than 200 °C. The results obtained by differential calorimetry showed a noticeable decrease in the calorific capacity of the nanocomposite compared to that of the pure material, especially for temperatures higher than 200 °C. The essential role of anisotropy in determining the thermal expansion characteristics of the nanocomposite was revealed. [ABSTRACT FROM AUTHOR]

Due to its mechanical, rheological, and chemical properties, high-density polyethylene (HDPE) is commonly used as a material for producing the pipes for transport of various media. Low thermal conductivity (0.4 W/mK) narrows down the usage of HDPE in the heat exchanger systems. The main goal of the work is to reduce the vertical depth of the HDPE pipe buried in the borehole by increasing the thermal conductivity of the material. This property can be improved by adding certain additives to the pure HDPE matrix. Composites made of HDPE with metallic and non-metallic additives show increased thermal conductivity several times compared to the thermal conductivity of pure HDPE. Those additives affect the mechanical properties too, by enhancing or degrading them. In this research, the thermal conductivity and tensile properties of composite made of HDPE matrix and two types of additives, expanded graphite (EG) and boron nitride (BN), were tested. Micro-sized particles of EG and two different sizes of BN particles, micro and nano, were used to produce composite. The objective behind utilizing composite materials featuring dual additives is twofold: firstly, to enhance thermal properties, and secondly, to improve mechanical properties when compared with the pure HDPE. As anticipated, the thermal conductivity of the composites exhibited an eightfold rise in comparison to the pure HDPE. The tensile modulus experienced augmentation across all variations of additive ratios within the composites, albeit with a marginal reduction in tensile strength. This implies that the composite retains a value similar to pure HDPE in terms of tensile strength. Apart from the enhancement observed in all the aforementioned properties, the most significant downside of these composites pertains to their strain at yield, which experienced a reduction, declining from the initial 8.5% found in pure HDPE to a range spanning from 6.6% to 1.8%, dependent upon the specific additive ratios and the size of the BN particles. [ABSTRACT FROM AUTHOR]

This document discusses the progress in engineering polymeric materials and the importance of understanding their mechanical, electrical, and thermal properties. The use of modern materials in manufacturing is crucial for addressing global environmental pollution and achieving sustainable development. The document emphasizes the need for research and testing of new materials, particularly in the context of recycling and technological advancements. It also highlights the development of eco-innovative materials and the use of composites and polymer blends in various industries. The authors stress the importance of collaboration and knowledge exchange in achieving advancements in material recycling and energy recovery. [Extracted from the article]

The configuration of a continuous and oriented thermal pathway is essential for efficient heat dissipation in the oriented direction. Three-dimensional (3D) conductive filler structures provide a suitable approach for constructing continuous thermal pathways in polymer-based composites. The aluminum nitride/reduced graphene oxide/poly(dimethylsiloxane) (AlN/rGO/PDMS) composite material is made with a 3D foam structure and focuses on reducing GO and forming foam via polyvinyl alcohol (PVA). We analyze the successful fabrication of hybrid fillers and composites using various methods. The fabricated composite with a 3D network filler foam achieves a through-plane thermal conductivity of 1.43 W/mK and achieves 752% higher thermal conductivity compared to pure PDMS, which is superior to composites without 3D foam. The continuous 3D filler structure via freeze-drying and annealing processes provides efficient thermal dissipation in the through-plane direction pathway, which is critical for enhancing thermal conductivity. Therefore, this work produces a polymer composite material with improved thermal conductivity through various processes. [ABSTRACT FROM AUTHOR]

In the recent years, additive manufacturing (AM) has been widely expanded for manufacturing the polymer and polymer-based composite parts. The main drawback of the material extrusion additive manufactured parts is the weaker mechanical properties in comparison to the manufactured parts by the conventional methods. The stated weak mechanical properties are due to the weak adhesion between the deposited layers. The poor adhesion between the deposited layers in material extrusion additive manufacturing process is due to the fact that the previous deposited filament (n-1) is already cooled and solidified. To ensure the appropriate adhesion between the two adjacent filaments, the temperature of the first deposited layer (n-1) has to be high enough to obtain a suitable adhesion to the subsequent layer (n) but in an optimum range to avoid the lack of the dimensional accuracy. Therefore, a precise and local measurement of the temperature on the scale of the diameter of the filaments is necessary. In this study, four important process parameters (liquefier temperature, layer height, print speed, and bed platform temperature) were selected to study their effects on the rheological behavior and temperature evolution of the PA6 and CF-PA6 materials during material extrusion process. Then, the impact of the short/chopped reinforcement on the thermal and mechanical properties of the material extrusion additive manufacturing processed polymer-based composites were studied by comparing the obtained results from PA6 and CF-PA6 parts. In one experiment, it was observed that increasing the liquefier temperature from 220 to 240 °C increased the tensile strength and crystallinity percentage of the manufactured PA6 and CF-PA6 specimens. It was determined that the crystallinity percentages of PA6 and CF-PA6 specimens increased from 12.51 to 14.40% and from 19.97 to 20.51%, respectively. One of the existence effects of carbon fibers is highlighted in the higher crystallinity values of the CF-PA6 specimens comparing PA6 specimens. Finally, a time–temperature-transformation diagram was plotted to determine the processability condition of the utilized materials. It can be helpful for the designers and researchers to find out the optimal material extrusion additive manufacturing process parameters condition for the utilized raw materials. [ABSTRACT FROM AUTHOR]

Hemp is a good option for polyethylene additives because of its high cellulose and fibrous content. This study aims to modify natural hemp fibers with the maleic anhydride/ionic liquid method, manufacture the composites, and compare the thermal and mechanical properties of natural hemp fiber and hemp cellulose. In this study recycled polyethylene as a binder, and filling ratios between 0 and 50 (wt/wt)% are investigated as a parameter. Differential scanning calorimeter and thermomechanical analysis were performed, and it was determined that the coefficient of thermal expansion from 973 to 147 ppm/K. It was determined that the strength of composite materials obtained from cellulose fibers with maleic anhydride/liquid ionic modification improved by around 20% from 19.5 to 24.4 MPa. In addition, as a result of scanning electron microscope analyses performed on the fractured surfaces, it was determined that the pressure, temperature, and time were suitable for producing composite materials. This work shows the potential of recycled polyethylene/hemp composites as a sustainable green material with simple fabrication procedure and useful mechanical and thermal properties. [ABSTRACT FROM AUTHOR]

Most of the energy savings in the building sector come from the choice of the materials used and their microphysical properties. In the present study, through numerical simulations a link is established between the thermal performance of composite materials and their microstructures. First, a two-phase 3D composite structure is modeled, then the RSA (Random Sequential Addition) algorithm and a finite element method (FE) are applied to evaluate the effective thermal conductivity of these composites in the steady-state. In particular, building composites based on gypsum and clay, consolidated with peanut shell additives and/or cork are considered. The numerically determined thermal conductivities are compared with values experimentally calculated using the typical tools of modern metrology, and with available analytical models. The calculated thermal conductivities of the clay-based materials are 0.453 and 0.301 W.m−1 .K−1 with peanut shells and cork, respectively. Those of the gypsum-based materials are 0.245 and 0.165 W.m−1 .K−1 with peanut shells and cork, respectively. It is shown that, in addition to its dependence on the volume fraction of inclusions, the effective thermal conductivity is also influenced by other parameters such as the shape of inclusions and their distribution. The relative deviations, on average, do not exceed 6.8%, which provides evidence for the reliability of the used approach for random heterogeneous materials. [ABSTRACT FROM AUTHOR]

This paper describes the preparation of new PEG6000–silica-MWCNTs composites as shape-stabilized phase change materials (ssPCMs) for application in latent heat storage. An innovative method was employed to obtain the new organic–inorganic hybrid materials, in which both a part of the PEG chains, used as the phase change material, and a part of the hydroxyl functionalized multiwall carbon nanotubes (MWCNTs-OH), used as thermo-conductive fillers, were covalently connected by newly formed urethane bonds to the in-situ-generated silica matrix. The study's main aim was to investigate the optimal amount of PEG6000 that can be added to the fixed sol–gel reaction mixture so that no leakage of PEG occurs after repeated heating–cooling cycles. The findings show that the optimum PEG6000/NCOTEOS molar ratio was 2/1 (~91.5% PEG6000), because both the connected and free PEG chains interacted strongly with the in-situ-generated silica matrix to form a shape-stabilized material while preserving high phase-transition enthalpies (~153 J/G). Morphological and structural findings obtained by SEM, X-ray and Raman techniques indicated a distribution of the silica component in the amorphous phase (~27% for the optimum composition) located among the crystalline lamellae built by the folded chains of the PEG component. This composite maintained good chemical stability after a 450-cycle thermal test and had a good storage efficiency (~84%). [ABSTRACT FROM AUTHOR]

To make the polyimide (PI) composite material having both heat resistance and magnetic permeability, Fe3O4/PI magnetic polyimide composite powder was synthesized by one-step solvothermal method. 4,4'-diaminodiphenyl ether (ODA) as monomers, ether anhydride polyamic acid (PAA) was designed and prepared by Fe3+ and polyimide precursor-polyamic acid triethylamine salt (PAAS) was reacted in a reactor, and the PI/Fe3O4 composite powders were synthesized under the condition of high temperature and high pressure. The obtained PI/Fe3O4 composite powders were analyzed by infrared spectroscopy, microscopic morphology and thermal properties. The morphology and structure of the samples were both characterized by scanning electron microscopy (SEM) and infrared spectroscopy (IR). The thermal properties of the composite microspheres were studied via thermogravimetric analysis (TGA) and the magnetic properties were determined by a vibrating sample magnetometer (VSM). The saturation magnetization decreases gradually, increasing the polyimide content, with a saturation magnetization of PI/Fe3O4 determined to be 20.29 emu/g. [ABSTRACT FROM AUTHOR]

In the present paper, we report polymer composites based on phenolic resin filled with hexagonal boron nitride; hot compression molding coupled with solution-based mixing were used to manufacture the composites. The paper presents experimental results on the physical and physicochemical properties of the obtained composites: thermal stability in air and argon, dielectric constant and dielectric loss tangent, active electrical resistance, thermal conductivity (mean and anisotropy), and mechanical strength. It is shown that the proposed technique of composite manufacturing, including the application of high-process pressures, makes it possible to obtain materials with high anisotropy of thermal conductivity, extremely high-filler content, and excellent dielectric properties, all of which are very important for prospective highly efficient lightweight heatsink elements for electronic devices. Experimental values of thermal conductivity and dielectric constant were analyzed using known mathematical models. Experimental values for thermal conductivities (up to 18.5 W·m−1·K−1) of composites at filler loadings of 65–85 vol.% are significantly higher than published data for bulk boron nitride/polymer composites. [ABSTRACT FROM AUTHOR]

The thermal conductivity of the composite materials based on the commercial ZnO micropowder with/without reduced graphene oxide (0.5 vol.%) powder dispersed in the polymethylsiloxane (silicone oil) is measured using the radial heat-flow method. The thermal conductivity of the composite material based on the commercial ZnO micropowder with an average particle size of 50 µm is found to be of 1.2 W/(m· K). The thermal conductivity of the composite material on the base of ZnO and reduced graphene oxide is found to be of 7.5 W/(m· K). At room temperature, the values of the dielectric permittivity at the measuring electric-field frequencies of 50 Hz and 1 MHz as well as the specific bulk electrical resistance for the composites are obtained. The large values of the thermal conductivity and the dielectric permittivity as well as lower specific bulk electrical resistance of the reduced graphene oxide–ZnO composite are associated with the contribution of reduced graphene oxide, the Maxwell– Wagner–Sillars interfacial polarization, and formation of the microcapacitor structures. It is also necessary to take into account that water could be adsorbed onto the powders’ surface in the process of composites’ fabrication. The high performance of reduced graphene oxide–ZnO composite synthesized by the simple and facile process in this work shows promising potential in thermal control of the electronic devices. [ABSTRACT FROM AUTHOR]

This work reports the effect of tin (Sn) doping on the infrared (IR) and terahertz (THz) properties of vanadium dioxide (VO 2 ) films. The films were grown by hydrothermal synthesis with a post-annealing process and then fully characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and temperature-controlled electrical resistivity as well as IR and THz spectroscopy techniques. Utilizing (NH 4 ) 2 SnF 6 as a Sn precursor allows the preparation of homogeneous Sn-doped VO 2 films. Doping of VO 2 films with Sn led to an increase in the thermal hysteresis width while conserving the high modulation depth in the mid-IR regime, which would be beneficial for the applications of VO 2 films in IR memory devices. A further analysis shows that Sn doping of VO 2 films significantly affects the temperature-dependent THz optical properties, in particular leading to the suppression of the temperature-driven THz transmission modulation. These results indicate Sn-doped VO 2 films as a promising material for the development of switchable IR/THz dichroic components. [ABSTRACT FROM AUTHOR]

The aim of this work is to study the mechanisms of polymorphic transformations in ZrO2 ceramics doped with MgO with different concentrations during thermal isochronous annealing, as well as the effect of the phase composition of ceramics on the change in strength properties and resistance to mechanical stress. Solving the problem of polymorphic transformations in zirconium dioxide by doping them with MgO will increase the resistance of ceramics to external influences, as well as increase the mechanical strength of ceramics. According to the data of X-ray phase analysis, it was found that the addition of the MgO dopant to the composition of ceramics at the chosen thermal annealing temperature leads to the initialization of polymorphic transformation processes, while changing the dopant concentration leads to significant differences in the types of polymorphic transformations. In the case of an undoped ZrO2 ceramic sample, thermal annealing at a temperature of 1500 °C leads to structural ordering due to the partial removal of deformation distortions of the crystal lattice caused by mechanochemical grinding. During the study of the effect of MgO doping and polymorphic transformations in ZrO2 ceramics on the strength properties, it was found that the main hardening effect is due to a change in the dislocation density during the formation of a ZrO2/MgO type structure. At the same time, polymorphic transformations of the m—ZrO2 → t—ZrO2 type have a greater effect on hardening at low dopant concentrations than t—ZrO2 → c—ZrO2 type transformations. [ABSTRACT FROM AUTHOR]

The Raman polymerization index (or IP value) is often used as a positive indicator of the firing temperature of the glazes of ancient ceramics. Previous studies have also reported that the IP value was negatively correlated with the chemical composition of the glaze. However, these findings were derived from data on the potential integrative effects of temperature and composition. To explore their individual effects, we prepared celadon glaze samples with controlled composition and firing temperatures. Particularly, according to the typical content of K2O and CaO in celadon glaze, four categories, or, in total, fifteen compositional formulations, were designed, and each formulation was fired at multiple temperatures (from 1180 to 1250 °C by 10 °C). The chemical compositions and the glassy matrix of samples were analyzed by an energy-dispersive X-ray fluorescence spectrometer and Raman spectroscopy, respectively. A positive correlation between firing temperature and IP value (correlation coefficient = 0.56) was detected only in the samples with low contents of K2O and CaO. However, no significant correlation was found when combining the samples with broad variation in chemical composition. Additionally, both the K2O content and CaO content were negatively related to the IP value, with regression coefficients of −9.645 and −5.332, respectively. Our results help to clarify the technology of ancient ceramic production and to improve its preservation. [ABSTRACT FROM AUTHOR]

The tailored physical properties of TiO2 are of significant importance in various fields and, as such, numerous methods for modifying these properties have been introduced. In this study, we present a novel method for doping Fe into TiO2 via the anodic dissolution of iron. The optimal conditions were determined to be an application of 200 V to acetylacetone (acac)/EtOH medium for 10 min, followed by the addition of TiO2 to the solution, sonication for 30 min, stirring at 80 °C, and drying. The resulting powder was calcined at 400 °C for 3 h, and characterization was conducted using XRD, FTIR, TEM, and UV-vis. The synthesized powder revealed the successful doping of Fe into the TiO2 structure, resulting in a decrease in the optical band gap from 3.22 to 2.92 eV. The Fe-TiO2 was then deposited on a metal substrate via the electrophoretic (EPD) technique, and the weight of the deposited layer was measured as a function of the applied voltage and exposure time. FESEM images and EDX analysis confirmed that the deposited layer was nanostructured, with Fe evenly distributed throughout the structure. [ABSTRACT FROM AUTHOR]

Analysis of the microstructure of electro-porcelain is important to better understand its influence on mechanical, electrical and aging behavior. The microstructures of two electro-porcelain materials with low and high quartz contents were analyzed with respect to the distribution of quartz. Using an adequate evaluation of EDS (energy dispersive spectroscopy) mapping data, a reproducible analysis of the size distribution and quantity of quartz was achieved. The method allows the analysis of large areas (12.5 mm2). Therefore, the probability of occurrence for a few large quartz grains could be determined. Independent of the overall amount of quartz in the materials, a wide distribution of the grain size was observed. The size of the large detected quartz grains in both materials was very similar. Around the large quartz particles, microcrack systems with lengths of several 100 µm were observed. They are linearly correlated with the equivalent circle diameter of the quartz grains. The evaluation of the cracks allowed us to determine the critical size below which no cracks around the quartz particles are formed. This size is approximately 10 µm. [ABSTRACT FROM AUTHOR]