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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]

In this study, a highly dense GdB 6 bulk ceramic material was fabricated using one-step in-situ reaction spark plasma sintering technology. The sample with a relative density of 96.7 % and a purity of 96.9 wt% was successfully obtained by sintering at 1800 °C for 30 min under a uniaxial pressure of 50 MPa. The Vickers hardness, elastic modulus and fracture toughness of the as-obtained GdB 6 bulk ceramics were 18.9 GPa, 209 GPa and 1.6 MPa·m1/2, respectively. The thermal conductivity of GdB 6 at room temperature was 28.68 W·m−1·K−1, 70 % of which was mainly attributed to phonon vibration, while the remaining 30 % to the electrical thermal conductivity. In addition, the as-obtained GdB 6 ceramics showed no phase transformation after heat treatment at a relatively high temperature of 2100 °C for 20 min in Ar atmosphere. The highly covalent octahedral boron framework played a critical role in maintaining the phase stability of the GdB 6 crystal lattice. This suggested that GdB 6 ceramics could be used as potential ultra-high temperature ceramics for aerospace applications and high-power vacuum electronic devices operated at high temperatures. [ABSTRACT FROM AUTHOR]

In this study, a novel bio-based composite of starch/plant fiber foaming tableware material was prepared by the hot-pressing foaming method. The influence of the content of carboxymethyl cellulos (CMC) as a new type of film-forming agent filler on the properties of foam materials was systematically investigated. The results showed that the foam material with 10 wt% CMC had excellent cell morphology and uniform cell size (the average cell size reached the minimum value of 465.7 μm), relatively high porosity (57.01%), and excellent thermal insulation properties (thermal conductivity: 0.0541 W/m·K). The tensile strength of foam increased from 4.289 MPa for 0 wt% CMC to 5.714 MPa for 10 wt% CMC loading. Similarly, the flexural strength also increased from 11.609 MPa to 15.719 MPa for the foam material with 10 wt% CMC. The thermal stability and viscoelastic properties of the foam material reached the highest after adding 10 wt% CMC. In addition, the increase of CMC content is beneficial to improve the oil resistance and biodegradability of the material. The research shows that CMC is an effective filler to improve the properties of starch/plant fiber foaming tableware materials, which can greatly promote the development of bio-based polymer foam materials. [Display omitted] • Starch/plant fiber foaming tableware material was prepared via a simple hot-pressing foaming method. • CMC was used as film-forming agent to optimize the properties of foam materials. • The addition of an appropriate amount of CMC (10 wt%) makes the cell size smaller and the cell structure more uniform. • CMC can improve the mechanical properties, thermal stability, viscoelasticity and thermal insulation of foam materials. • This new type of foam tableware material can be completely biodegradable under natural conditions within 21 days. [ABSTRACT FROM AUTHOR]

In this work, Cu-1.5 wt%Y (Cu-Y) and Cu-0.75 wt%Y-0.75 wt%La (Cu-Y-La) were prepared by mechanical alloying combined with spark plasm sintering and hot rolling, followed with annealing at different temperatures. The effects of the introduction of La and annealing temperatures on the microstructures, mechanical properties, electrical conductivity and thermal stability of Cu-Y alloys were investigated. Both Cu-Y and Cu-Y-La obtain the heterogeneous mixed grain structures composed of coarse grains and fine grains, and oxide nanoparticles are uniformly dispersed in Cu matrix. With the introduction of La, the grains and oxide nanoparticles are refined, and LaYO 3 nanoparticles with the coherent interfacial structure can be observed in Cu-Y-La. After annealing at 500 ℃, both Cu-Y and Cu-Y-La obtain the most excellent comprehensive tensile properties and highest electrical conductivity (63 %IACS for Cu-Y and 62 %IACS for Cu-Y-La). Benefited from effectively enhanced grain boundary strengthening and particle strengthening mechanisms induced by the combination effect of La and Y, Cu-Y-La shows higher strength than that of Cu-Y (after annealing at 500 ℃, 244 MPa of yield strength for Cu-Y and 300 MPa for Cu-Y-La). Meanwhile, benefited from improved dynamics stability of the Cu matrix induced by significantly refined precipitates and the formation of LaYO 3 nanoparticles with the coherent interfacial structure after introducing La, the better softening resistance is achieved by Cu-Y-La in comparsion with Cu-Y, and almost 100 ℃ improvement of the softening temperature is achieved (966 ℃ for Cu-Y-La and 870 ℃ for Cu-Y). • A novel system of Cu-Y-La alloy for the field of ITER is designed and prepared. • Effects of heat treatment on microstructure and properties of Cu alloys reinforced by rare earth elements are studied. • The significant improvement of mechanical property of Cu-Y alloy is achieved through the combination effect of Y and La. • The softening resistance of Cu-Y alloy is successfully improved through the combination effect of Y and La. [ABSTRACT FROM AUTHOR]

Enhancing the mechanical properties and thermal stability of phthalonitrile polymers by hybrid modification holds significant importance in broadening their thermal-structural applications within high-temperature environments. Herein, fumed silica nanoparticles were considered as modifiers for a class of phenolic-type phthalonitrile resin, i.e., PN75, and their effects on mechanical properties and thermal stability were explored. First, contact angle tests (CA) were employed to show that the PN75 melt had good wettability on hydrophilic fumed silica (FS) and poor wettability on hydrophobic fumed silica (RFS). FS had a relatively satisfactory dispersion within PN75, which was indicated by scanning electron microscope (SEM), followed by FS/PN75 nanocomposites were prepared by melt blending under vacuum, with maximum FS addition 3 wt% of PN75. Second, the flexural strength and modulus of nanocomposites were increased by 23.5% and 11.9%. Finally, thermal stability of the FS/PN75 was promoted from 21.6% to 25.6% in char residue at 800 °C in the air atmosphere by the thermogravimetric analysis (TGA), which was contributed by the high heat-resistance and the shielding effect of FS. This work would inspire in-depth studies on modification and design of phthalonitrile-based hybrid composites for extreme thermal environment. [Display omitted] • Hydrophilic fumed silica exhibited well wettability with phenolic-type phthalonitrile resin. • Vacuum melt blending was proven as an efficient process achieving well dispersion of fumed silica nanoparticles. • Addition of fumed silica into phthalonitrile polymers improved the flexural strength and the char residue. [ABSTRACT FROM AUTHOR]

As an environmentally friendly material, alkali-activated fly ash-slag (AAFS) is considered as a promising alternative cement because of its excellent mechanical properties and thermal stability. Nevertheless, high temperature induced damage in AAFS can potentially bring serious risks for its practical applications. This paper presents a systematic experimental study on behaviour of AAFS paste subjected to elevated temperatures up to 800 °C in terms of microstructure as well as thermal and mechanical properties. Microstructural evolution was characterised by means of Rietveld-based quantitative X-ray diffraction (QXRD), backscattered scanning electron microscope (BSEM) and X-ray microcomputed tomography (XCT), while thermal and mechanical properties were evaluated from thermogravimetric analysis (TGA), thermal deformation and compressive and flexural strengths. Results indicate that the compressive strength of AAFS paste rises by 77.5 % at 200 °C, followed by a mitigation from 200 to 600 °C and a regain at 800 °C. Different phases in AAFS paste including unreacted particles, reaction products and pores took up 30 %, 67.7 % and 2.31 % at ambient temperature, and 4.95 %, 84.8 % and 10.3 % after exposure to 800 °C, respectively, suggesting the recrystallisation with the formation of nepheline and gehlenite. In addition, the relationships between microstructural characteristics including three-dimensional (3D) pore structure features and thermal and mechanical properties of AAFS paste at elevated temperatures were explored and discussed in depth to gain insights into the underlying degradation mechanisms including pore pressure build-up, thermal gradient and phase transformation. [ABSTRACT FROM AUTHOR]

This study investigates the mechanical properties and microstructure evolution of Al 2 O 3 -4J42 joints brazed using Ag–Cu–Ti (ACT) and Ag–Cu–Ti/Cu/Ag–Cu (ACTCA) fillers during thermal cycling from 0 °C to 500 °C. The reaction products between Al 2 O 3 and brazing filler of these two types of joints are mostly composed of Ti–O compounds, Ti 4 Cu 2 O and Al-based compounds. Brittle intermetallic compounds (IMCs) are observed in ACT joints, but not found in ACTCA joints. The reaction layer in ACT joints becomes thinner and discontinuous with thermal cycles, while that in the ACTCA joints hardly changes. Besides, the stress-induced cracks occur within the Al 2 O 3 ceramic near the Al 2 O 3 /filler interface in the ACT joints, but no crack is found in the ACTCA joints. The mechanical tests show that the ACTCA joints maintain at least 217%, 154% and 144% higher shear strength than the ACT joints at 0, 10 and 20 thermal cycles, respectively. The Cu interlayer with low yield strength releases stress through plastic deformation, meanwhile acts as a barrier to prevent elements diffusion and the formation of the brittle IMCs, thus improving the mechanical properties and thermal cycling stability of the joints. [ABSTRACT FROM AUTHOR]

In the frame of developing sustainable, eco-friendly and high performance materials, microcrystalline cellulose modified through silane coupling agent (MCC Si) is used as a reinforcing agent of benzoxazine resin to manufacture composites at different loadings of 5, 10, 15, 20 wt%. The structural, morphological and crystallinity characterizations of the modified MCC were initially performed to scrutinize the changes and confirm the modification. Then, an investigation on the crosslinking process of the prepared composites was held through curing kinetic study employing isoconversional methods. The kinetic data revealed a decrease in the average values of activation energy and the pre-exponential factor, particularly for composite supplemented with 10% MCC Si, whereas all samples disclosed a tendency of an autocatalytic curing mechanism. Furthermore, the study of the dynamic mechanical properties and degradation features of the cured specimens, respectively, indicated a superior stiffness attributable to the good interaction between BA-a and MCC Si, and enhanced thermal stability for the composites compared to pristine resin. • Microcrystalline cellulose was functionalized using silane coupling agent. • The structural, thermal and morphological occurring changes on MCC were investigated. • Effect of MCCSi on the curing kinetic, dynamic-mechanical properties and thermal stability of benzoxazine is studied. [ABSTRACT FROM AUTHOR]

Oligocellulose (OC) with low polydispersity indices has been produced in large quantities using an improved method of acid-assisted hydrolysis, in which long cellulose chains disintegrate in concentrated phosphoric acid at moderately elevated temperatures. The hydrolysis time has been reduced by three orders of magnitude without compromising the overall yield of the process or the quality of OC products. The efficient production of high-quality OCs in large quantities allows for developing OC-derived elastomeric materials. A series of OC- graft -poly(isobornyl methacrylate- random - n -butyl acrylate) [OC- g -P(IBOMA- r -BA)] elastomers have been synthesized via activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP). OC- g -P(IBOMA- r -BA) elastomers have tunable molecular architectures and phase morphologies toward desirable mechanical properties and thermal stability suitable for various applications. The methodologies of the OC production and the graft -polymers synthesis in this study would help advance technologies for broader applications of bio-based elastomers. [Display omitted] [ABSTRACT FROM AUTHOR]

The demand for biopolymer-based green packaging has attracted growing attention because of its outstanding properties and consistency with clean environmental principle, unfortunately, its slow crystallization rate and narrow processing window are challenging. Inspired by combined functions in nanocellulose-based conductive hybrids, this work developed high-performance polylactic acid (PLA) composites using conductive cellulose nanofiber (CNFene). Interestingly, CNFene has multiple functions as highly graphitized carbon and abundant hydroxyl groups, delivering stimulating properties to PLA composites. As nucleating agents, 3 wt% CNFene has a carbon layer on the surface combined with a hydrogen bonding network synergistically enhancing the tensile and crystallization properties of PLA-C3, with a tensile strength of ∼ 53.7 MPa, crystallinity of ∼ 33.9 %, and 6.6 °C decrease in the cold crystallization temperature. Additionally, the compatibility between CNFene and PLA can form a multi-level "reinforcement" network structure, further improving thermal stability and barrier properties. The resultant PLA-C3 showed higher thermal decomposition onset temperature (T 0), wider melt-processing window (197.6 °C) and extremely lower overall migration levels in ethanol (68.6 μg/kg) and isooctane (16.3 μg/kg), due to that improved interaction between CNFene and PLA positively affects crystallization ability and kinetic/mechanism of PLA to meet the requirements of industrial and green biopackaging applications. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Bio-based copolyesters involving 2,6-pyridine structure with isosorbide as a second diol were synthesized. • Incorporation of isosorbide enhanced thermal properties of the pyridine-based polyesters. • Isosorbide significantly improved the mechanical properties of the pyridine-based polyesters. • The copolyesters showed high gas barrier properties. Driven by sustainable development and low-carbon policies, many high-performance bio-based polyesters are produced. Our previous work uncovered the high barrier but low thermal and mechanical properties of a renewable 2,6-pyridinedicarboxylic-based polyester. In this article, the copolymerization with isosorbide as a second diol is considered to ameliorate these properties. The chemical structures of copolyesters and the successful introduction of isosorbide were confirmed by FT-IR and 1H NMR. The 1H NMR spectra also allowed the calculation of isosorbide ratio in polymers. GPC revealed a decrease in molar masses with the increase of isosorbide ratio. Contact angle and water/gas permeation measurements disclosed an increase in hydrophilicity and water/gas permeability with the introduction of isosorbide. TGA and DSC analyses demonstrated an enhancement in thermal stability: 8 mol% of isosorbide to the total diol ratio increased the 5 % weight loss temperature (T 5%) by 9 °C, the maximum weight loss temperature (T max) by 8 °C and the glass transition temperature (T g) by 6 °C. DSC investigation showed that the incorporation of isosorbide significantly influenced the crystallization properties, particularly from the melt, by decreasing the crystallinity. XRD patterns indicated the presence of similar crystallization units in these polyesters. Tensile test revealed that incorporating 8 mol% of isosorbide greatly improved the mechanical properties by doubling Young's modulus and tripling the strength at break. Such enhancement in thermal and mechanical properties is important for high gas barrier food packaging applications of these polyesters. [ABSTRACT FROM AUTHOR]

The preparation of biobased benzoxazine resin with low melting point and low curing temperature has important significance for environmental sustainable development and practical application in industrial field. In this paper, biobased benzoxazine monomer HA-fa was synthesized from p-hydroxybenzyl alcohol, paraformaldehyde and furfurylamine, and H-fa were prepared by Mannich reaction of hordenine with paraformaldehyde and furfurylamine. The two benzoxazine organic molecules showed different thermodynamic behaviors. HA-fa and H-fa were liquid at room temperature. The viscosity of HA-fa and H-fa at room temperature (25 °C) were 1.683 Pa/s and 0.602 Pa/s, and the curing peak temperature was 220 °C and 208 °C, respectively, both organic molecules showed excellent processability. Then poly(HA-fa) and poly(H-fa) were prepared by two organic molecules through thermal curing procedure. The comprehensive properties of two benzoxazine resins were investigated. The glass transition temperature (T g) of poly(H-fa) is 223 °C, while the T g of poly(HA-fa) has two peak temperatures, 225 °C and 281 °C, respectively. This may be due to the existence of two different crosslinking networks in the resin, which leads to the phase separation of the resin, thus reflecting two T g. Meanwhile, the initial thermal decomposition temperatures T di of poly(HA-fa) and poly(H-fa) were 330 °C and 331 °C, respectively, showing excellent thermal stability of the newly prepared resin. In addition, poly(HA-fa) and poly(H-fa) have both high storage modulus (3174 MPa and 2608 MPa, respectively, measured at 25 °C) and good flexural strength (121 ± 2.7 MPa and 96 ± 3.6 MPa). Among the two resins, poly(HA-fa) showed more excellent comprehensive properties, which may be based on the joint action of resin multi-crosslinking sites and hydrogen bond crosslinking network. Two benzoxazine monomers have low viscosity at room temperature, they also have low curing temperature, both monomers showed excellent processability. [Display omitted] • Two benzoxazine monomers have low viscosity at room temperature, both monomers showed excellent processability. • Results demonstrate that poly(HA-fa) and poly(H-fa) showed excellent comprehensive properties. • The nature behind these attractive performances of poly(HA-fa) and poly(H-fa) was intensively investigated. [ABSTRACT FROM AUTHOR]

In this study, PDC added with tantalum was successfully prepared via high pressure and high temperature (HPHT, 7.7GPa and 1650 °C) with the Cubic-Anvil Press. The effect of tantalum on the mechanical properties and thermal stability was systematically investigated by hardness, abrasion resistance, impact resistance and coefficient of thermal expansion (CTE) tests. The results showed that the hardness, wear ratio, total impact energy and initial expansion temperature increased by 21.7%, 45.5%, 55.2% and 20 °C with the addition of tantalum, respectively. The Ta-PDC material binder phase consisted of Ta-phases (TaC, (Ta,W)C X) and cobalt phase after sintering. In elemental quantification observe that the addition of Ta facilitated cobalt infiltration which was benefit to diamond-diamond bonding. The improvement of mechanical properties and thermal stability can be attributed to the reinforced binder, refined and deagglomerated WC grains at the interface between PCD layer and substrate, and better sintering quality. Further optimization of the Ta additive phase content, mixing methodology, or sintering conditions could be explored to further improve the mechanical properties and thermal stability of this novel PDC material. • Adding Ta can promote the sweeping of cobalt. • Adding Ta greatly refined and de-agglomerated the WC grains at the interface. • Adding Ta enhanced the mechanical properties and thermal stability of PDC. [ABSTRACT FROM AUTHOR]

In this work, Cu-1.4 wt%Ta-Zr alloys with different Zr content (0, 0.1, 0.2 and 0.5 wt%) were fabricated by mechanical alloying combined with spark plasm sintering. The effect of Zr addition on the microstructures, mechanical properties and thermal stability of Cu-Ta alloy were characterized. Cu-Ta alloys composes of ultrafine equiaxed grains along with the uniformly dispersion of semi-coherent Ta nanoclusters and incoherent Ta coarse particles. As Zr is introduced into Cu-Ta alloy, the Ta precipitates were effectively refined, especially for the reduction of Ta coarse particles. The significant refinement effect of the grains is realized when Zr content reaches 0.2 wt%, and high-proportioned nano-sized grains are facilitated to form, along with the activation of a lot of twins and the formation of intermetallic composed of Cu and Zr. The dislocation density and strength increase remarkably with the increase of Zr content, and the highest strength (499 MPa for yield strength and 600 MPa for ultimate tensile strength) is achieved as the Zr content is up to 0.2 wt%. Compared with Cu-Ta alloy (382 MPa for yield strength and 560 MPa for ultimate tensile strength), the significant increment of 31% for the yield strength is successfully realized by Cu-Ta-0.2 wt%Zr alloy. Cu-Ta-0.2 wt%Zr alloys exhibit the excellent thermal stability, and the hardness keeps stable even the sample was annealed at 700 °C for 300 h, showing superior microstructural stability in comparison with Cu-Ta alloy (∼4.5% reduction of the hardness after 300 h at 700 °C). The softening temperature of Cu-Ta-0.2 wt%Zr alloy is up to 1028 °C (1022 °C for Cu-Ta alloy) along with higher hardness than that of Cu-Ta alloy at the same annealing temperature. This study provides a new way to fabricate dispersion strengthened Cu alloys with high strength, exceptional thermal stability and softening resistance, which have great potential application value in the field of future fusion reactor. [Display omitted] • A novel system of Cu-Ta-Zr alloy for the field of DEMO with low cost is designed and prepared. • Ta coarse particles in Cu-Ta alloy are effectively refined by the introduction of Zr. • The significant enhancement of yield strength of Cu-Ta alloy is achieved by adding 0.2% Zr. • The excellent combination of high strength, exceptional softening resistance and thermal stability is successfully achieved. [ABSTRACT FROM AUTHOR]

A major challenge in the chronic wound healing is a self-care wound dressing. The problem in chronic wounds is the lack of functional extracellular matrix to stimulate healing. The extracellular matrix is a network of proteins and polysaccharides that serves as physical framework and provides regulatory signals. The primary goal is to mimic the property of the extracellular matrix with Silk Fibroin and Paramylon to produce a novel bioactive film. Silk fibroin is a fibrous protein having unique mechanical properties and tunable biodegradability that makes it favourable for tailoring to specific applications. Paramylon is a β-glucan that possess a broad spectrum of biological activity that enhances the immune response. Silk fibroin/paramylon blend films have been prepared by solution casting and were examined for structural, thermal, mechanical and other physical properties for knowing its transformation for chronic wound healing. It was observed that the fibroin films shows high thermal stability, high hydrophobicity, high stiffness value whereas the paramylon film show good water absorption property and both fibroin and paramylon shows good blood compatibility and was non-toxic as well. It also confirms that the blended films showed a combination of fibroin and paramylon property at different concentrations without any chemical interaction. [ABSTRACT FROM AUTHOR]

• Lightweight concrete containing scrap-tyre-rubber-based aggregate. • A wide set of structural, mechanical, thermal and hygric properties. • Improved thermal performance, approved thermal stability up to 300 °C. • Unaffected water transport parameters, while water vapour transition increased. • Non-bearing lightweight material having benefits to the environment and economy. Increasing amount of waste tyres represents a global problem as tyres can pose a risk to the environment if not treated properly. Recycling of waste tyre rubbers in civil engineering as aggregate in cement concrete can be an effective environmental and economic approach. As problems associated with the use of waste tyre rubber in concrete production are not completely understood, a detailed analysis of rubber concrete prepared from used tyre rubber-based aggregate involving testing of its mechanical, basic physical, microstructural, hygric and thermal properties, and behaviour after exposure to elevated temperatures is presented in this paper. Testing of mechanical performance included measurement of compressive strength, flexural strength, secant and dynamic modulus of elasticity. Thermal conductivity was determined in the dependence on moisture content, from the dry to fully water saturated state. Dry volumetric heat capacity was also tested. Specific attention was paid to the hygric performance of rubberized concrete that was characterised by the water and water vapour transport parameters. Investigation of concrete properties after its thermal exposure included testing of mass loss, mechanical resistance, bulk density, and thermal conductivity that was tested as property having direct relation to concrete structural parameters. The use of scrap-tyre-rubber aggregate resulted in a decrease of the unit weight, worsening in mechanical parameters and a significant reduction in thermal conductivity of prepared rubberized concrete. Rubber-based aggregate almost did not affect water transport properties, while water vapour transport properties increased with rubber amount in the mix. No significant changes on concrete characteristics related to rubber incorporation occurred at temperatures up to 300 °C. However, after exposure to 400 °C, significant changes in measured concrete properties were observed, which was in line with the thermogravimetric analysis of the used tyre-based rubber. Nevertheless, based on rubberized concrete functional properties at common ambient conditions it can be considered as an alternative lightweight material, bringing benefits to the environment and economy as it is produced from crap available in a large amount and at a negligible cost. [ABSTRACT FROM AUTHOR]

In the present paper, diphenylamine-4-sulfonic acid sodium salt and silica nanoparticles are introduced into poly (vinyl alcohol) (PVA) matrix to improve the thermal and mechanical properties through crosslinking with glutaraldehyde (GA) under acidic conditions. Proton conductivity, ion exchange capacity, and swelling ratio are examined as a function of the crosslinking degree. The membranes showed a degree of crosslinking between 6.1 and 33%. XRD experiments revealed that the amorphous character of the newly developed PVA membranes is improved by increasing the amount of GA. FE-SEM observations confirmed a major change of the surface morphology owing to the variation of GA content. It is also demonstrated that the proton conductivity decreased by increasing the crosslinker content and its maximum value, 6 × 10−2 (S/cm), is obtained for the membrane having 2 wt% of glutaraldehyde. Results showed that the methanol permeability decreased by increasing the concentration of GA. The prepared membrane consisting 5 wt% of silica nanoparticles showed the best thermal and mechanical properties. • Crosslinked PVA-sulfonic acid salt-silica NP S hybrid membranes synthesized and characterized • Proton conductivity of the membranes reduced by increasing crosslinking degree. • Hybrid membranes showed better mechanical and thermal stability. [ABSTRACT FROM AUTHOR]

Graphical abstract Densely interconnected 3D BNNS networks for isotropically thermal conductivity epoxy composites with reduced filler-filler thermal resistance via a novel thermally AgNPs welding strategy. Highlights • BNNS@AgNPs are prepared via a ball milling method and in-situ reduction treatment. • Interconnected 3D BNNS networks formed by thermally sintered AgNPs structures. • The silver bridges serve as thermal transport junctions in the 3D filler network. • The mechanical and thermal stability of composites are improved simultaneously. Abstract Polymer-based thermal conductive composites (PTCs) with good thermal and mechanical properties are highly appreciated in the thermal management of modern electronic devices. However, the heat transfer property of particle-filled PTCs is severely limited by the thermal resistance at both filler-matrix and filler-filler interfaces. Intensive efforts have been taken to enhance the filler-matrix interface, however, the effect of filler-filler thermal contact resistance on the heat transfer properties of PTCs is still not very clear. In this work, continuous thermal conductive networks with good filler-filler interface contact are formed in epoxy composites via the in-situ sintering of silver nanoparticles on the surface of boron nitride nanosheets (BNNS). In this composites, homogeneously dispersed and well exfoliated BN nanosheets are bridged to each other via the sintered AgNPs located at the BNNS and a 3D boron nitride nanosheets network is formed with solid Ag junctions lying in between. After thermal sintering process, the thermal conductivity of EP/BNNS@AgNPs composite with the 3D boron nitride nanosheets network increase from 0.95 W/m·K to 1.13 W/m·K at the filler loading of 20 wt%, which indicates that merged AgNPs are used as thermal transport junctions to reduce the thermal contact resistance within 3D BNNS networks. The present strategy provides an effective route for developing high-performance PTCs. [ABSTRACT FROM AUTHOR]

In this work, we provide a holistic picture about the relationship between atomic structure, mechanical properties, and thermal stability of ZrCuAl x thin film metallic glasses (TFMGs) varying the Al content from 0 to 12 at.%, carrying out a broad characterization involving experiments and ab initio molecular dynamic simulations (AIMD). We show that the addition of Al resulted in a change of average interatomic distances by ∼10 pm with the formation of shorter bonds (Al-Zr and Al-Cu), influencing the mechanical response (shear/elastic moduli and hardness) which increases by ∼15% for 12 at.% Al. Moreover, tensile tests on polymer substrate revealed a maximum value for the crack initiation strain of 2.1% for ZrCuAl 9 , while the strain-to-failure rapidly decreases at higher Al contents. The observed reduction in damage tolerance is correlated to a transition in atomic configuration. Specifically, a maximum in density of full and defective icosahedral cluster population is observed at 9 at.% Al, inducing a more shear-resistant behavior to the material. Thermal stability is investigated by high-energy and conventional x-ray diffraction and electrical resistivity measurements as a function of the temperature. Glass transition (T g) and crystallization (T x) temperature increase by Al addition reaching 450 and 500 °C, respectively for ZrCuAl 12. The increase in thermal stability is related to the reduction in atomic mobility due to the formation of shorter chemical bonds, inhibiting atomic reconfiguration during crystallization. In conclusion, we provide guidelines to the design of compositional-tailored ZrCuAl x TFMGs with tuned mechanical properties and thermal stability with potential impact on industrial applications. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The as-deposited AlCrFeCoNiCu 0.5 films were annealed at 500 °C for up to 72 h. • Four new phases were formed during the 72 h of annealing. • The formation of a new heterogeneous nanocomposite thin film was revealed. • A 30% enhancement of mechanical properties was achieved after 72 h annealing. • The as-annealed thin films exhibited superior thermal stability. High entropy alloy (HEA) films offer excellent mechanical properties due to their random solid solution structure. However, their large grain boundary volume fraction can cause thermal instability, resulting in phase decomposition that affects their high-temperature performance. Nevertheless, it remains an interesting question whether phase decomposition can be used as a processing tool to create new HEA materials. In this study, AlCrFeCoNiCu0.5 HEA thin films were fabricated and annealed at 500 °C for up to 72 h. The 72-hour annealed thin film exhibited a 30 % increase in mechanical properties, exceeding most other HEA thin films. Characterization using X-ray and electron microscopy revealed a decomposition-induced phase transformation, which produced four new phases, including Cu-rich FCC phase, Cr-rich BCC phase, and ordered B2 phase of AlNi and FeCo. The enhanced mechanical properties were due to back stress strengthening and BCC + B2 phase strengthening. The 72-hour annealed thin film also showed excellent thermal stability through a new round of annealing, exhibiting a low variation in microstructure and chemical composition after being annealed at 500 °C for 100 h. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel Sc/Zr/Ti/Er modified Al-Cu alloy was successfully fabricated by wire-arc directed energy deposition technology. • The fine equiaxed grain structure was obtained due to the heterogeneous nucleation caused by the primary Al3X dispersoids. • Homogenization prefabricates more Al3X dispersoids, which promote the transition from θ″ to θ′ precipitate. • Homogenization ripens the existing pores, resulting in a better tensile isotropy. In this study, a novel Sc/Zr/Ti/Er-modified 2219 aluminum alloy was designed and wall-shaped components were then fabricated by wire-arc directed energy deposition (DED). Due to the heterogeneous nucleation promoted by primary Al 3 X dispersoids, the as-deposited alloy exhibits a highly equiaxed fine grain structure. Two heat treatment schedules were conducted to tailor the strength and thermal stability of the alloy. Compared with the classical T6 heat treatment, the additional homogenization step before the T6 heat treatment (HT6) prefabricated more Al 3 X dispersoids, which indirectly promoted the transition from θ″ precipitates to θ′ precipitates, resulting in a slight reduction in strength. However, this homogenization step helps to avoid the aggregation of pores by promoting pores ripening and significantly alleviates the anisotropy of ductility. In addition, the better thermal stability of the HT6 heat treated alloy is due to more Al 3 X dispersoids and finer θ′ precipitates with high coarsening resistance caused by the segregation of Sc and Mn at the θ′/Al interface during thermal exposure. In general, the wire-arc DEDed micro-alloyed 2219 Al alloy exhibits a promising combination of strength and ductility after heat treatment and its mechanical properties are superior to those of the wrought micro-alloyed Al-Cu alloys. [ABSTRACT FROM AUTHOR]

Continuous carbon fiber (CCF) reinforced polymeric composites have attracted significant attention in the aeronautic and automobile industries. In this study, novel CCF/poly(ether ether ketone) (PEEK) composites with robust solvent resistance, excellent thermal stability and outstanding mechanical properties were successfully fabricated via a facile solution impregnation process, mainly ascribed to the introduction of the crosslinkable phenylethynyl pendant to PEEK (PEP-PEEK) with excellent solubility. After the crosslinking reaction, PEP-PEEK presented robust solvent resistance, good thermal stability, and high mechanical properties. The longitudinal tensile strength of the CCF/PEP-PEEK composites significantly improved to 1610 MPa, which was 19 times stronger than the longitudinal tensile strength of PEP-PEEK. In the meantime, the CCF/PEP-PEEK composites also had a higher long-term operating temperature, excellent thermal stability and high heat distortion temperature. This study was performed as part of a larger effort to provide a simple and feasible method for the preparation of high quality continuous fiber reinforced poly(ether ether ketone) composites. [ABSTRACT FROM AUTHOR]

In this work, we investigated the effect of boron addition on glass-forming ability and mechanical properties of Co-Cr-Mo-C alloys. The starting alloy was (Co 0.65 Cr 0.13 Mo 0.22 ) 80 C 20 derived from the Co 65 Cr 13 Mo 22 ternary eutectic composition. This alloy is almost fully crystalline and exhibits brittle mechanical properties. Replacing carbon with boron allows obtaining bulk metallic glasses (BMGs) and bulk metallic glass composites. The designed alloys show very high strength (∼4100 MPa), wide super-cooled liquid region (∼100 K) and large endothermic enthalpy of the supercooled liquid region (∼35 J/g), indicating high thermal stability. The electronegativity difference and supercooled liquid region of the present alloys are comparable to rare-earth elements containing BMGs. The physical properties of the present alloys corresponded well with the alloy design strategy based on the unified parameter using the glass transition temperature, fracture strength, and molar volume. Furthermore, we propose the optimum compositional condition for glass formation by controlling the carbon-to-boron ratio and the influence of carbon on phase formation in this alloy system is discussed. [ABSTRACT FROM AUTHOR]

Bulk nanostructured n-type PbTe (0.2 wt% PbI 2 ; 0.3 wt% Ni) and p-type Ge 0.96 Bi 0.04 Te were prepared by grinding the synthesized materials in a planetary ball mill followed by compaction by spark plasma sintering. Hardness, Young's modulus and stiffness of the synthesized and nanostructured thermoelectric materials were investigated by nanoindentation. Nanostructured thermoelectric materials have significantly higher mechanical properties than synthesized materials, and grinding time have small effect on the hardness, Young's modulus and stiffness. The efficiency of nanostructured thermoelectric materials in the entire range of operating temperatures is 10–14% higher than that of the materials obtained by hot pressing. The maximum values of dimensionless thermoelectric figure of merit for nanostructured thermoelectric materials on the basis of PbTe and GeTe are equal to 1.34 and 1.43, respectively. The increase in the efficiency is explained by the scattering of phonons by inhomogeneities of the nanocrystalline structure. Thermal treatment at a temperature of 750 K for 72 h reduced dimensionless thermoelectric figure of merit by not more than 2% and 3% for GeTe and PbTe nanostructured thermoelectric materials, respectively. Repeated differential scanning calorimetry showed that nanostructured thermoelectric materials are thermally stable up to 850 K. The grinding time does not affect the thermal stability of materials. According to thermogravimetry sublimation of thermoelectric materials begins above 850 K. To ensure long-term use of thermoelectric materials on the basis of PbTe and GeTe in the temperature range of 850–900 K it is necessary to use protective Si 3 N 4 or SiO 2 coatings. • Nanostructured thermoelectric materials were developed for range of 600–900 K. • The mechanical properties of nanostructured thermoelectric materials were studied. • Complex investigation of thermal and electrical properties was carried out. • Mechanisms of electrical and thermal conductivities were determined. • Thermal stability of developed materials was determined in the range of 300–900 K. [ABSTRACT FROM AUTHOR]

In this study, a high-strength and heat-resistant Al–Ce–Sc–Zr alloy was designed and fabricated by additive manufacturing. The as-built alloy shows an excellent combination of strength and ductility compared to other Al–Ce-based alloys, including an ultimate tensile strength of 445 MPa, a yield strength of 344 MPa and an elongation of 10%. Even at 300 °C, the alloy still retains a superb tensile yield strength of 233 MPa, which is the best among the high-temperature aluminum alloys reported so far. The excellent performance is mainly attributed to a significant amount of fine, homogeneous and coarsening-resistant Al 11 Ce 3 intermetallic nanoparticles formed during the rapid solidification process of laser additive manufacturing. The formation of coherent Al 3 (Sc, Zr) nano-precipitates and interfacial segregation at the interface of intermetallic nanoparticles during high temperature exposure further improve the high temperature properties of the alloy. Our work has the potential to provide design concepts for the development of novel high temperature aluminum alloys. • The rapid cooling rates during additive manufacturing produce a high volume fraction of nanoscale Al 11 Ce 3 intermetallic. • Thermal exposure promotes the precipitation of Al 3 (Sc, Zr) in matrix and the segregation of Sc/Zr at Al/Al 11 Ce 3 interface. • The combined role of Al 11 Ce 3 intermetallic and Al 3 (Sc, Zr) nano-precipitates contributes to excellent mechanical properties. • The Al–Ce-Sc-Zr alloy exhibits a high tensile yield strength of 233 MPa at 300 °C. [ABSTRACT FROM AUTHOR]

The research evaluated the properties of cold-mixed epoxy asphalt (EA) and cold-mixed epoxy styrene–butadiene–styrene (SBS)-modified asphalt (ESA) for paving steel-deck bridges. Compared with ESA, EA showed longer pot life and better processability at ambient temperature, as revealed by curing rheology analysis. The cured EA showed higher glass-transition temperature, superior thermal stability, tensile strength and elongation at breaking than ESA. These may be as a result of: (i) the high thermal stability of asphalt, (ii) the formation of a cross-linking network in the cured material, and (iii) the good compatibility between the epoxy resin and the asphalt. [ABSTRACT FROM AUTHOR]

The microstructure design strategy is introduced to improve the mechanical property of a novel γ-Ti-43.5Al-6.5Nb-1.5Cr-0.5C/TiB 2 metal matrix composite (MMC) fabricated by hot isostatic press (HIP). With increasing the content of TiB 2 from 0 to 3 wt%, the average grain size, {001} maximum texture index and average schmid factor of HIP-processed Ti-43.5Al-6.5Nb-1.5Cr-0.5C/TiB 2 parts generally decrease from 27.4 μm, 7.9 and 0.43 to 22.7 μm, 4.1 and 0.38, in addition, the crystallographic texture transforms from the mixture of (001) and (111) orientations to a strong (101) orientation. The phases evolution mechanism in the HIP-processed Ti-43.5Al-6.5Nb-1.5Cr-0.5C/TiB 2 parts can be divided into four steps: first of all, β phase transforms to γ and α phases, then, a small amount of new phases of TiB and TiC emerge by the diffusion of Ti and C atoms, subsequently, the β and α orderly transform to B 2 and α 2 , lastly, the B 2 , α 2 , TiB 2 , TiB and TiC uniformly distribute in the γ matrix. Both the tensile strength and strain of HIP-processed Ti-43.5Al-6.5Nb-1.5Cr-0.5C/TiB 2 components increase from 471.9 MPa and 1.7% to 653.4 MPa 2.1% with the increase of TiB 2 content from 0 to 3 wt%. [ABSTRACT FROM AUTHOR]

Conventional polyimide nanocomposites reinforced with graphene-based nanofillers usually possess excellent properties, such as high thermal decomposition temperature, enhanced tensile strength, tensile modulus, etc. However, the elongation at break of the nanocomposites is reduced. Here, we prepared N-doped graphene quantum dots/colorless polyimide nanocomposite (N-GQDs/CPI) films for the first time by in-situ polymerization, whose elongation at break is about 2 times that of the pure film. Meanwhile, the thermal properties and other mechanical properties of the films are improved. Through analyzing FT-IR, XPS, XRD, TAG SEM, etc. of N-GQDs and the films, we consider that the strengthening mechanism of matrix performance is attributed to N-GQDs' well dispersion, its small size effects and strong interface interaction with the matrix. Furthermore, at the indicative wavelength of 550 nm, the optical transmittance of the film with 1 wt% N-GQDs still maintains 79%, indicating the resulting films have excellent optical transmittance. The hydrophilic properties of the prepared films' surface is reduced, their water surface contact angle are increased from 63 ± 2.7° to 92 ± 1.7° with the content of N-GQDs increasing. This research shows that N-GQDs can enhance the various properties of polyimide and provides a high performance nanocomposite films for potential flexible substrates. [ABSTRACT FROM AUTHOR]

Thermal and mechanical properties of polylactide (PLA) composites with different grades of calcium carbonate, 40 nm and 90 nm nanoparticles, and also with submicron particles, unmodified and modified with calcium stearate or stearic acid, obtained by melt mixing, were compared. Films with amorphous and crystalline matrices were prepared and examined. T g of PLA in the composites remained unaffected whereas its cold crystallization was enhanced by the fillers and predominantly depended on filler content. Filling decreased thermal stability of the materials but their 5% weight loss temperatures well exceeded 250 °C, evidencing stability in the temperature range of PLA processing. The amorphous nanocomposites with modified nanoparticles exhibited improved drawability and toughness without a significant decrease of tensile strength; nearly two-fold increase of the elongation at break and tensile toughness was achieved at 5 wt% content of the modified nanofiller. Lack of surface modification of the filler, larger grain size with an average of 0.9 μm, and matrix crystallinity had a detrimental effect on the drawability. However, the presence of nanofillers and crystallinity improved tensile modulus of the materials by up to 15% compared to neat amorphous PLA. [ABSTRACT FROM AUTHOR]

The morphology and properties of blends of PP/HDPE and MAPP/HDPE blends, and their composites with wood powder, were investigated in this paper. The blends showed two-phase morphologies, and MAPP interacted better than PP with HDPE, while the WP interacted more strongly with MAPP. Although the different components in the blends were immiscible, they showed one crystallization peak. MAPP and HDPE showed separate crystallization peaks in the composites, and this separation of the crystallization became more resolved with increasing WP content and at lower cooling rates. This was also observed for PP and HDPE in their composites, but to a lesser extent. Young’s modulus increased and the stress at break decreased with increasing WP content, and these were more pronounced in the PP/HDPE/WP composites. Interaction between WP and MAPP also had an influence on elongation at break. The presence of WP increased the thermal stability of the MAPP/HDPE and PP/HDPE. [ABSTRACT FROM AUTHOR]

Our pilot research revealed that the dielectric constant of polyimide (PI) can be reduced and the modulus can be improved by assembling necklace-like interlocking complexes with crown ethers. Not only did we find that these properties of the PI complex still cannot adequately meet the demand of practical applications but also that there was a deterioration in its thermal stability. A functional octa(aminopropyl)silsesquioxane (OAPrS) with a significantly rigid Si-O-Si cage was incorporated into an 18-crown-6 (CE6)-PI (CE6-PI) complex to produce inorganic-organic OAPrS/CE6-PI nanocomposites. By exploiting the synergetic effect of OAPrS and CE6, most properties of the PI were clearly improved. In the case of 3.9 wt% OAPrS and 7.8 wt% CE6, the dielectric constant of PI was reduced by 30%, and Young's modulus and the tensile strength were increased by 106% and 23%, respectively. In addition, the thermal stability of the CE6-PI complex was modified, and its 5% weight loss temperature and glass transition temperature were increased by 31.2 and 11.2 °C, respectively, with the incorporation of 3.9 wt% OAPrS. The indispensable nano-reinforcing role of aggregated OAPrS crystal in the nanocomposite was carefully analysed and verified. [ABSTRACT FROM AUTHOR]

In the field of bioabsorbable composites for biomedical applications, extrusion has been employed as a method to prepare homogeneous blends of polymeric matrices with bioactive ceramic fillers. In this work, the suitability of processing poly- l -lactic acid/Magnesium (PLLA/Mg) composites by hot extrusion has been assessed by a systematic characterization of PLLA/Mg composites containing different amounts of Mg particles up to 7 wt%. The results show that extrusion causes a reduction of almost 20% in the viscosity average molecular weight of PLLA, which further decreases with increasing Mg content. Extrusion gave always rise to a homogeneous distribution of Mg particles within the PLLA matrix. This composite processing was not compromised by the degradation of the polymeric matrix because the processing temperature was always below the onset degradation temperature. In the processing conditions employed in the present work, degradation of the composite slightly increases as more Mg is added up to 5 wt%, but is very high at 7 wt%. This was also evident from the mechanical behaviour, so that Mg particles improved the stiffness and compression strength of neat PLLA until 5 wt% of Mg content, which dropped drastically when the material had 7 wt% of Mg. The filler strengthening factor decreases with the increment in Mg content. In order to obtain an optimised contribution of Mg particles, a balance between thermal degradation and mechanical resistance of PLLA must be achieved. [ABSTRACT FROM AUTHOR]

Tin oxide (SnO 2 ) has versatile applications in a variety of areas. It also shows ability to improve the flame retardancy of flexible poly(vinyl chloride) (fPVC) composite and substitute the conventional toxic flame retardant-antimony trioxide (Sb 2 O 3 ). However, low flame retardant efficiency and ruined thermal stability of the PVC composite in presence of SnO 2 remain to be the most prominent challenges. To address these issues, in this study, hematite (α-Fe 2 O 3 ) zero-dimensional nanoparticles elaborately encapsulated SnO 2 one-dimensional nanorod assemblies and such nanocasting facilitated the formation of hierarchical porosity in favor of high specific surface area and pore volume. The hierarchically nanoporous hybrid was synthesized via a facile and fast bottom-up method in a large scale and all-sided characterization was conducted on the investigation of its structure and fPVC compositions. The extra benefits imparted by α-Fe 2 O 3 in the hybrid improved the flame retardancy of fPVC composite strikingly with reduced amount of harmful HCl gas and suppressed smoke production, without deterioration of thermal stability and mechanical property, showing much better performance than those of Sb 2 O 3 -based fPVC composite. It indicated that this new eco-friendly nanohybrid had a great potential to totally replace antimonial additive. It is expected to pave the pathway about the construction of neoteric porous hybrid nanostructures and open a new avenue to develop high performance nanocomposites. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multifunctional P/Ni-doped g-C 3 N 4 (Ni-P-C 3 N 4) nanoflakes were synthesized. • Ni-P-C 3 N 4 can be homogeneously dispersed in ABS by simple melt-blending. • Ni-P-C 3 N 4 endowed ABS with enhanced thermal stability and mechanical strength. • Ni-P-C 3 N 4 significantly improved the flame retardancy and smoke suppression of ABS. The ubiquitous application of highly flammable acrylonitrile–butadienestyrene (ABS) resin has brought great fire threat to human and environment. Unfortunately, current flame retardants often improve flame retardancy but reduce mechanical and thermal properties, seriously affecting their practical application. We herein reported novel multifunctional, high-efficiency, phosphorus and nickel co-doped graphitic carbon nitride (Ni-P-C 3 N 4) nanoflakes to address the trade-off between flame retardancy and mechanical/thermal properties. The addition of 2.0wt% of Ni-P-C 3 N 4 increased the initial degradation temperature and tensile strength of ABS composite (ABS/Ni-P-CN2) by 15 °C and 24.3% relative to virgin ABS, indicating its positive effect on thermal and mechanical properties. Compared with ABS, ABS/Ni-P-CN2 exhibited a notable increase in time to ignition, along with 32.4% and 33.8% reductions in peak heat release rate (PHRR) and peak smoke production rate (PSPR), demonstrating excellent anti-ignition, flame-retardant and smoke-suppressive performances. The increased fire safety was mainly due to the physical barrier effect of g-C 3 N 4 nanosheets and the catalytic charring effect of P and Ni. This work offers a novel design strategy to create multifunctional flame retardants for fabricating fire-safe polymer composites with superior thermal and mechanical properties, holding great potential in industries. [ABSTRACT FROM AUTHOR]

This paper used phthalazinone-based copoly(biphenyl ether nitrile) (co-PPEN) to improve the low-temperature toughness of epoxy resin E51. The effects of co-PPEN content on the normal/low-temperature mechanical properties, thermomechanical properties, and thermal stability of epoxy resins were studied. Results showed that co-PPEN significantly improved the normal/low-temperature mechanical properties of E51. At room temperature, the impact strength, flexural strength, and tensile strength of co-PPEN/E51 blends increased by 144.0%, 12.8%, and 28.1%, respectively; at low temperature, the impact strength, flexural strength, and tensile strength of co-PPEN/E51 blends increased by 87.9%, 43.6%, and 18.5%, respectively. From the cross-sectional analysis, the crack deflection and crack bridging of co-PPEN are the main toughening mechanisms of the blends. The blend system has high thermal property, and the glass transition temperature of the co-PPEN/E51 blend increased by about 50 °C. Simultaneously, all blends exhibited better thermal stability. [Display omitted] • High-performance thermoplastic co-PPEN engineering plastic toughened epoxy resin. • Modified co-PPEN/E51 composites have good low-temperature properties (−183 °C). • Modified co-PPEN/E51 composites have good thermal properties. [ABSTRACT FROM AUTHOR]

Starch based wood nanocomposites (WSNC) were prepared successfully from starch and soft wood with multi-walled carbon nanotube (MWCNT) as nano reinforcing agent through a completely green path. The most important part of this scheme was the use of water as the solvent. In this technique, starch was grafted with methylmethacrylate (MMA) and MWCNT was functionalised with hydroxyl groups ( f -MWCNT). Dimethyloldihydroxyethyleneurea (DMDHEU) was used as a cross-linker to prepare the green material from methylmethacrylate grafted starch (MMA- g -starch), soft wood flour and functionalised MWCNT. The functionalization of MWCNT was confirmed by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and Raman analysis. Different properties of the WSNC were investigated by varying the concentration of f -MWCNT. The prepared nanocomposites exhibited outstanding thermal stability, mechanical properties and water resistance capacity compared to untreated wood composites. The flammability of the wood composites decreased up to 30% with just addition of 0.50 phr f -MWCNT. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel magnolol-based epoxy monomer and two furfuryl amines with various side groups were synthesized. • The furfuryl amine containing benzene has a faster curing rate. • The fully bio-based epoxy resin has a high Tg of 168 °C. • The fully bio-based epoxy resins exhibit excellent mechanical and thermal properties. With rapidly shrinking petroleum resources and the deteriorating environment, the use of renewable green bio-based resources to replace petroleum-based raw materials and the development of new bio-based epoxy resins are hot topics of research today. In this study, a new bio-functional epoxy monomer based on magnolol (EMDBP) and two different curing agents based on furfuryl amine with various side groups (PDFA and BDFA) were synthesized and utilized to produce two sets of fully bio-based epoxy thermosets. The non-isothermal and isothermal curing kinetics of EMDBP/PDFA and EMDBP/BDFA were systematically investigated using different scanning calorimetry (DSC) according to the Friedman isoconversional differential method and model-fitting approach, respectively. The results indicate that the autocatalytic curing mechanism dominated the curing reaction of the fully bio-based curing system at a low conversion stage whereas diffusion controlled the curing reaction at a high conversion stage. With an attached benzene ring, BDFA has a more reactive amine group than PDFA. Thus, the curing reaction rate of the BDFA curing system was much faster than that of the PDFA curing system, which also increased significantly with temperature. Additionally, the glass transition temperature of the EMDBP systems (T g , 151.3 °C and 168.4 °C) was increased by 71.3% to 95.7% compared to the diglycidyl ether of bisphenol A (E51) systems (T g , 77.3 °C and 98.3 °C), which was also higher than those of most previously reported fully bio-based epoxy resins. Analysis by nanoindentation and tensile testing showed that the Young's modulus, hardness, tensile strength, and modulus of EMDBP systems were also greatly improved. Furthermore, thermogravimetric investigations demonstrated that EMDBP systems possessed excellent thermal stability at high temperatures, with a char yield of about 47.5 wt% at 800 °C. Consequently, these novel fully bio-based epoxy thermosets with superior heat resistance, mechanical properties, and thermal stability have the potential to replace commercial epoxy resins and be utilized under high temperature environments. [ABSTRACT FROM AUTHOR]

The mechanical, thermal, and barrier characteristics of an epoxy biocomposite coating made using rice husk biomass biosilica were investigated in this study. The primary objective of this research was to find out whether and how adding biosilica from biomass rice husks improve the polymeric coating material's properties and adopted as sustainable coating element. The thermo-chemical approach and an aqueous solution method were adopted to transform the rice husk ash into the biosilica and in silane treated form. The ultrasonicator was used to mix the biosilica particles with resin to create the composite coating material. The prepared coating material was then characterized using ASTM standards in order to evaluate the effects of biosilica addition. According to the results, the tensile and flexural properties were improved by the inclusion of silica particles up to 1 and 2 vol%. However the properties are reduced when the biosilica amount was increased up to 4 vol%. In contrast, the hardness and thermal conductivity of the 4 vol% of biosilica dispersed composite was 94 shore-D and 0.42 W/mK, respectively. In terms of mass loss stability, the 4 vol% biosilica dispersed composite outperformed. After the biosilica particle was added, the barrier behavior showed good resistance to oxygen penetration. However, the stability of water permeation was moderately affected. As a coating material for corrosion-prone metallic surfaces and other household coating applications, these mechanically enhanced, thermally strengthened, and barrier property strengthened biosilica-epoxy composites could be applied. • Silane treated rice husk ash biosilica epoxy coatings were successfully prepared. • Mechanical properties of coatings are improved with RHA Biosilica content. • Thermal stability of coatings are improved with RHA Biosilica content. • Highest hardness achieved was 94 Shore-D, which is highly preferred in coating. • Barrier properties were improved as biosilica content improved. [ABSTRACT FROM AUTHOR]

Simultaneously enhancing the thermal conductivity, insulation, and mechanical properties of high-density polyethylene (HDPE) composites is highly desired for electronic and electrical applications. In this research, HDPE/boron nitride (BN)/coconut shell charcoal (CSC) composites were prepared. Benefit from the synergistic effect between the multi-dimensional hybrid fillers, the prepared HDPE/BN/CSC composites exhibited enhanced comprehensive properties compared to the HDPE/BN composites and pure HDPE. In particular, as for HDPE/25BN/3CSC (25 wt% BN, 3 wt% CSC) nanocomposites compared to the pure HDPE, enhancements in in-plane thermal conductivity of 980.89%, normal thermal conductivity of 138%, and tensile strength of 18.91% were obtained, while higher volume resistivity and decomposition temperature were achieved. This work provides a simple but effective way for improving the thermal conductivity and comprehensive physical properties of HDPE composites. • HDPE/BN/CSC composites were prepared. • High thermal conductivity of the HDPE/BN/CSC composites were achieved. • Thermal stability, mechanical properties, and insulation properties were all enhanced at appropriate CSC contents. [ABSTRACT FROM AUTHOR]

Cr x Ta 1-x N coatings were deposited by magnetron sputtering and the influence of the Cr/(Cr + Ta) ratio on microstructure, mechanical properties, thermal stability and oxidation resistance was investigated. X-ray diffraction revealed that all coatings exhibit an fcc-Cr x Ta 1-x N crystal structure with an increasing size of coherently diffracting domains as the Cr/(Cr + Ta) ratio increases. A balanced Cr/(Cr + Ta) ratio of 0.46 results in the highest hardness of 27.4 ± 1.0 GPa, whereas binary fcc-TaN was determined to have the highest Young's modulus of 417 ± 20 GPa. All Ta-containing coatings exhibit a K IC value of 2.40 ± 0.10 MPa × m1/2 and thus exceed the fracture toughness of CrN (1.53 ± 0.21 MPa × m1/2). While vacuum annealing at 1000 °C already provokes a decomposition of the binaries, N-deficient compounds only form in the ternaries at temperatures ≥1200 °C. The oxidation onset and end temperature as well as the phase composition of the oxides were found to depend significantly on the Cr/(Cr + Ta) ratio. Among the investigated coatings, Cr 0.75 Ta 0.25 N exhibits the most promising thermal stability, both in inert and oxidizing atmosphere. • Cr x Ta 1-x N coatings with varying Cr/(Cr + Ta) ratio were magnetron sputter deposited. • Compressive residual stress and hardness increase with decreasing Cr/(Cr + Ta) ratio. • Ternary Cr x Ta 1-x N coatings outperform CrN and TaN in regard of thermal stability. • Cr 0.75 Ta 0.25 N exhibits the best thermal stability and oxidation resistance. [ABSTRACT FROM AUTHOR]

Cr x Ta 1-x N coatings were deposited by magnetron sputtering and the influence of the Cr/(Cr + Ta) ratio on microstructure, mechanical properties, thermal stability and oxidation resistance was investigated. X-ray diffraction revealed that all coatings exhibit an fcc-Cr x Ta 1-x N crystal structure with an increasing size of coherently diffracting domains as the Cr/(Cr + Ta) ratio increases. A balanced Cr/(Cr + Ta) ratio of 0.46 results in the highest hardness of 27.4 ± 1.0 GPa, whereas binary fcc-TaN was determined to have the highest Young's modulus of 417 ± 20 GPa. All Ta-containing coatings exhibit a K IC value of 2.40 ± 0.10 MPa × m1/2 and thus exceed the fracture toughness of CrN (1.53 ± 0.21 MPa × m1/2). While vacuum annealing at 1000 °C already provokes a decomposition of the binaries, N-deficient compounds only form in the ternaries at temperatures ≥1200 °C. The oxidation onset and end temperature as well as the phase composition of the oxides were found to depend significantly on the Cr/(Cr + Ta) ratio. Among the investigated coatings, Cr 0.75 Ta 0.25 N exhibits the most promising thermal stability, both in inert and oxidizing atmosphere. • Cr x Ta 1-x N coatings with varying Cr/(Cr + Ta) ratio were magnetron sputter deposited. • Compressive residual stress and hardness increase with decreasing Cr/(Cr + Ta) ratio. • Ternary Cr x Ta 1-x N coatings outperform CrN and TaN in regard of thermal stability. • Cr 0.75 Ta 0.25 N exhibits the best thermal stability and oxidation resistance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Polyethylene glycol and toluene 2,4 diisocyanate (TDI) were used to synthesize polyurethane/zinc oxide (PU/ZnO) nanocomposites. • The presence of main functional groups was verified using FTIR spectra, and XRD patterns indicated hexagonal crystalline NPs with an average particle size of 33.8 nm. • TGA graphs revealed that increasing the concentration of ZnO nanoparticles enhanced the thermal stability of ZnO/PU. • With increasing nanofiller concentrations, the magnitude of Young's modulus continuously rose. The study presents the synthesis of polyurethane/zinc oxide (PU/ZnO) nanocomposites from polyethylene glycol (PEG, MW = 8000) and toluene 2,4 diisocyanate (TDI) within a temperature range of 40 to 60 °C. Structural confirmation and particle size of ZnO were carried out through SEM, FTIR spectroscopy and XRD. Structural insight through XRD presented hexagonal crystals with an average diameter of 33.8 nm. While thermal stability was investigated through thermogravimetric analysis (TGA). The PU/ZnO nanocomposite films were prepared in a Teflon petri dish using different percentages of ZnO; 2%, 4%, 6%, 8%, and 10% in stoichiometric amounts. Functional groups analysis was carried out through FTIR, and it showed the addition of ZnO within the polymer matrix. SEM analysis demonstrated that nanoparticles were homogeneously dispersed all over the polymer surface, responsible for the improvement of inherent properties. TGA study confirmed that homogeneously dispersed nanoparticles improved the thermal stability of polyurethane. The results of TGA graphs showed that the thermal stability of PU/ZnO nanocomposites was increased as the concentration of incorporated ZnO nanoparticles increased as compared to pure polyurethane. Mechanical properties of the nanocomposites were also improved in terms of maximum strain and stress at break, young's modulus and toughness owed to homogenous dispersion and better material properties. [ABSTRACT FROM AUTHOR]

Mo-0.5 wt%ZrC alloy plate with enhanced mechanical properties and thermal stability was manufactured by powder metallurgy and hot rolling. The as-rolled Mo-0.5%ZrC plate shows an ultimate tensile strength (UTS) of 725 MPa and a total elongation (TE) of 24.1% at room temperature. After annealing at 1300 °C, the UTS of Mo-0.5%ZrC alloy decreased to 676 MPa while the TE increased to 32.8%. After 1600 °C annealing, the UTS of Mo-0.5%ZrC alloy is 507 MPa and the TE increased significantly to 56.4%. Additionally, Mo-0.5%ZrC alloy exhibits a high recrystallization start temperature of about 1300 °C. The addition of nanoscale ZrC particles can enhance the strength and high temperature stability by pining dislocations and grain boundaries. Meanwhile, ZrC nanoparticles can also react with the impurity oxygen to form Zr–C–O or ZrO 2 particles, and thus alleviate the oxygen embrittlement of Mo alloy. However, the oxide particles tend to grow into larger particles at high temperatures, leading to decreased number density of dispersoids and lower dispersion-strengthening effect. • Mo-0.5%ZrC alloy plate shows enhanced mechanical properties and thermal stability. • The recrystallization temperature of Mo–ZrC alloy is 300 °C than that of pure Mo. • Recrystallized Mo-0.5%ZrC alloy shows excellent room-temperature ductility. • ZrC can react with O to form stable oxide and enhance the grain boundary bonding. [ABSTRACT FROM AUTHOR]

[Display omitted] • Compact and nanogranular ZrCu/O films were deposited by pulsed laser deposition and annealed to investigate thermal stability. • Nanogranular films crystallize at 300 °C, while the crystallization of compact films occurs >420 °C. • The Young's modulus and hardness increase with annealing temperatures due crystallization process, reaching 180 and 14 GPa for nanogranular films. • The residual stresses of compact films increase with annealing temperature, while for nanogranular ones they reach a maximum at 420 °C, indicating a complete crystallization. • The evolution of structural/mechanical properties is studied, considering film morphology, local chemistry and free volume. Binary ZrCu nanocomposite amorphous films are synthetized by pulsed laser deposition (PLD) under vacuum (2 × 10−3 Pa) and 10 Pa He pressure, leading to fully amorphous compact and nanogranular morphologies, respectively. Then, post-thermal annealing treatments are carried out to explore thermal stability and crystallization phenomena together with the evolution of mechanical properties. Compact films exhibit larger thermal stability with partial crystallization phenomena starting at 420 °C, still to be completed at 550 °C, while nanogranular films exhibit early-stage crystallization at 300 °C and completed at 485 °C. The microstructural differences are related to a distinct evolution of mechanical properties and residual stress, with compact TFMGs showing the highest values of Young's modulus (157 GPa), hardness (12 GPa), strain rate sensitivity (0.096), and local residual stress (+691 MPa) upon annealing at 550 °C, while nanogranular films reach the maximum values of mechanical properties at 485 °C followed by relaxation at higher temperatures due to complete crystallization. We show that PLD in combination with post-thermal annealing can generate different families of amorphous films with varying nanoscale morphologies, resulting in tunable mechanical properties and thermal stability, which can thus be used for designing novel film configurations for different fields of application. [ABSTRACT FROM AUTHOR]

In this work, in order to investigate the reinforcement effects of organic montmorillonite (OMMT) modified epoxy mortar binders (EMBs), a series of OMMT/EMB composites with different OMMT loadings were prepared. The structure and thermal stability of OMMT were studied by X-ray diffraction (XRD), Fourier transform infrared spectrum, and thermogravimetric analysis (TGA). The effects of OMMT on the structure, glass transition, damping properties, thermal stability, mechanical properties and morphology of EMB were characterized by XRD, dynamic mechanical analysis, TGA, tensile test, and scanning electron microscopy. XRD results indicated that epoxy chains intercalated into the OMMT layers and led to the expansion of OMMT layer spacing. The presence of OMMT increased the glass transformation temperature, crosslink density of the neat EMB. Furthermore, the incorporation of OMMT improved the thermal stability of the EMB. The OMMT/EMB composites showed higher tensile strength and Young’s modulus than the neat EMB. Homogenous dispersion of OMMT in EMB matrix was observed. [ABSTRACT FROM AUTHOR]

To develop high-performance dielectric materials, we report a novel strategy to fabricate core-shell structured BaTiO 3 @polymer nanoparticles through rotary coating technology combined with a post-treatment bonding process, by using carboxyl-functionalized poly(arylene ether nitrile) (CPAEN) as the polymeric surface-grafting agent. The results demonstrated that the CPAEN was chemically bonded on the surface of BaTiO 3 core through monodentate coordination of carboxyl groups, and the BaTiO 3 core was completely wrapped by a stable CPAEN shell with a uniform thickness of 4–7 nm. Furthermore, polymer nanocomposites were prepared by using core-shell structured BaTiO 3 @CPAEN nanoparticles as hybrid nanofillers and poly(arylene ether nitrile) (PAEN) as the polymer matrix. The results indicated that the nanocomposites exhibited enhanced dielectric properties, such as relatively high dielectric permittivity, quite low loss tangent and good permittivity-frequency stability, and excellent thermal stability, high mechanical strength and good flexibility. Therefore, it provides a path to obtain a new class of high-temperature-resistant dielectric materials for various engineering applications. [ABSTRACT FROM AUTHOR]

This study proposes a new approach to prepare polyimide (PI)-based nanocomposites containing amino groups functionalized graphene oxide (GO-NH 2 ) via in situ polymerization and thermal imidization. GO-NH 2 nanosheets which exhibit excellent dispersibility and compatibility with the PI matrix were successfully obtained through the chemical reaction between graphene oxide (GO) and p-phenylenediamine (PDA). The mechanical properties, thermal stability and hydrophobic behavior of the PI/GO-NH 2 composites were significantly improved compared with those of pure PI because of excellent dispersion of GO-NH 2 and the strong interfacial covalent bonds between GO-NH 2 and the PI matrix. With a 3 wt% GO-NH 2 loading, the tensile modulus of PI/GO-NH 2 nanocomposites was increased from 1930 MPa to 3139 MPa, and the tensile strength was increased from 101.5 MPa to 156.8 MPa, which were approximately 63% and 54.5% enhancement compared to the pure PI, respectively. The 10% weight loss temperature of PI/3 wt% GO-NH 2 is improved 24 °C compared with neat PI film (539.5 °C). Furthermore, the hydrophobic behavior of the composite films is greatly improved. This effective approach provides a strategy for developing high-performance and multifunctional polymer-based composite materials. [ABSTRACT FROM AUTHOR]

In this study, cement mortar with paraffin/expanded perlite materials was prepared by direct mixing method. The effect of paraffin/expanded perlite material content on mechanical and thermal properties of cement mortar were investigated. The experimental results showed that the paraffin was confined in the porous structures of expanded perlite by capillary force. The average mass percentages of paraffin in paraffin/expanded perlite material reached as high as 65%. It was a physical interaction between paraffin and expanded perlite. Compressive strength and flexural strength of cement mortar decreased with increasing amount of paraffin/expanded perlite materials. Cement mortar with 20 wt% paraffin/expanded perlite materials had good heat storage property and thermal stability compared to ordinary cement mortar. [ABSTRACT FROM AUTHOR]

We added montmorillonite (MMT) to improve the mechanical properties and thermal stability of poly (methyl methacrylate) (PMMA). We used a twin-screw extruder to produce standard specimens for examinations. We examined the layer distance of MMT and mechanical properties of the nanocomposites containing various amounts of MMT. The chemical structure and morphology of specimens were characterized with wide-angle powder X-ray diffraction, scanning, and transmission electron microscopy techniques. It was observed that by increasing the amount of MMT, layer distance increased from 2.16 to 3.87 nm for the composite containing 5 wt% MMT. In the tensile and impact properties examinations, the composite containing 1% MMT revealed the best result with increase of 1.81%. The shore hardness and wear resistance properties were also significantly improved. The beginning of thermal decomposition of nanocomposites slightly shifted to a higher temperature, compared with the thermogram of pure PMMA. [ABSTRACT FROM AUTHOR]

Thermal stability of a synthetic sand composition, which was developed as a simulant for calcium–magnesium aluminosilicate (CMAS) turbine deposits, was characterized using thermogravimetric and differential thermal analysis (TG/DTA). The sand was melted into CMAS glass, which had a composition of 23.3CaO–6.4MgO–3.1Al 2 O 3 –62.5SiO 2 –4.1Na 2 O–0.5K 2 O–0.04Fe 2 O 3 (mol.%), determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Bulk density of the glass was measured to be 2.63 g/cm 3 , and the Young's and shear moduli were 84.3 GPa and 33.6 GPa, respectively, along with a Poisson's ratio of 0.26. Vickers microhardness and indentation fracture toughness were determined to be 6.14 ± 0.1 GPa and 0.70 ± 0.05 MPa m 1/2 , respectively. Glass transition temperature, softening point and coefficient of thermal expansion of the glass were measured by dilatometry. Glass viscosities were estimated over a temperature range of 600–1500 °C using dilatometric reference points of the glass and from composition-based methods. Times required for infiltration of molten CMAS glass into thermal or environmental barrier coatings were also estimated. [ABSTRACT FROM AUTHOR]