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Aiming at the development of thermal environmental barrier coatings (TEBCs) material, the factor of grain size is introduced into the high-entropy rare-earth disilicate for the first time. The (Yb 0.2 Tm 0.2 Lu 0.2 Sc 0.2 Er 0.2) 2 Si 2 O 7 with smaller grain size was prepared by one-step pressureless sintering method. Results of thermal conductivity and coefficient of thermal expansion (CTE) reveal that thermal conductivity of (Yb 0.2 Tm 0.2 Lu 0.2 Sc 0.2 Er 0.2) 2 Si 2 O 7 bulk material is lower than that all existing EBCs and even most TBCs and potential TEBCs material, which is 0.686 W m−1 °C−1 at 1300 °C. Excellent thermophysical properties indicate that designed (Yb 0.2 Tm 0.2 Lu 0.2 Sc 0.2 Er 0.2) 2 Si 2 O 7 with small grain size can be used as a promising TEBCs material. • It is the first time to introduce the grain size into the thermal conductivity of high-entropy rare earth silicate materials. • The prepared (Yb 0.2 Tm 0.2 Lu 0.2 Sc 0.2 Er 0.2) 2 Si 2 O 7 has very low thermal conductivity than all existing EBCs materials. • (Yb 0.2 Tm 0.2 Lu 0.2 Sc 0.2 Er 0.2) 2 Si 2 O 7 with small grain size has excellent thermophysical properties and is a candidate for TEBCs. [ABSTRACT FROM AUTHOR]

Carbide dispersion for reinforcement is an effective strategy to enhance the performance of tungsten (W). High-entropy carbides (HECs), when compared to conventional carbides, offer superior thermal stability, hardness, mechanical strength, creep resistance, and wear resistance. This study represents the first successful incorporation of (HfNbTaZr)C as a reinforcing phase into a W matrix, resulting in the formation of a W-HEC alloy. Compared to other carbides such as ZrC, HEC demonstrates improved coherency with the W matrix, resulting in a significant increase in plasticity and enhanced high-temperature stability. This innovative approach paves the way for alloy design in high-temperature applications such as nuclear fusion, providing fresh insights into the enhancement of mechanical properties and thermal stability. • A (HfNbTaZr)C HEC has been synthesized, for the first time, incorporated as a reinforcing phase into the W matrix. • The mismatch between HEC(200) and W(110) is 0.018, smaller than the W-ZrC alloy, indicating better coherence with the W matrix. • The W-HEC demonstrates outstanding plasticity at 600 °C, displaying total elongation of 33.0%, surpassing other W alloys. • The W-HEC hardness decreases is less than the W-ZrC after annealing at 1800 °C, demonstrating superior thermal stability. [ABSTRACT FROM AUTHOR]

La(Fe,Si) 13 alloys are prone to display burst-like phenomena at their first-order ferromagnetic transition, such as a latent heat decomposed into a succession of heat flux avalanches. For some extreme cases, these phenomena are so pronounced that they can yield recalescence/antirecalescence events. It turns out that these features are also highly sensitive to the technical specificities of the employed measurement systems. Here, we compare the thermal events at the first-order magnetic transition of LaFe 11.4 Si 1.31 Co 0.29 using magnetization, two differential scanning calorimeters and a thermometry probe specially designed for the present study. These techniques are complementary to each other, and allow to make a distinction between the properties influenced by thermal coupling and those more intrinsic to the compound or to the sample. A simple thermal model is built to account for the thermal lags in the different devices, and to provide insights into the dependence of the duration of the transition on the thermal sweep rate. Looking in closer detail at the development of the transition, we found evidence of a rate independent initial regime, followed by a second one along which the same shape of temporal profile is spread over a more or less long duration depending on the sweep rate. Possible underlying mechanisms corresponding to these regimes are discussed. [Display omitted] • Comparative study including rarely considered Tzero DSC and thermometry probes. • A thermal model describes the complex dependency of transition duration on sweeping rate. • Detailed thermometry measurements confirm the reproducibility of the transition path. • A rate independent initial regime is observed from DSCs and thermometry measurements. [ABSTRACT FROM AUTHOR]

In this study, the effects of Ca addition on the microstructure, thermal properties, and mechanical properties of a Mg-6.0Zn-1.2Y-0.7Zr (ZWK611) alloy at room temperature and 150 °C were investigated. With an increase in the Ca content, the ignition resistance of the ZWK611 alloy improved and the grains became finer. The as-cast ZWK611 alloy consisted mainly of the dendritic α-Mg matrix and I-phase (Mg 3 Zn 6 Y) at the grain boundaries. On the other hand, the τ- (Ca 2 Mg 6 Zn 3) and I-phases were formed in the Ca-added ZWK611 alloy. The fraction of the τ-phase increased with an increase in the Ca content. After the solid-solution treatment, these phases remained partially at the grain boundaries of the Ca-added ZWK611 alloys and an additional W-phase (Mg 3 Zn 3 Y) was observed. The phases remaining at the grain boundaries restricted the grain growth through the grain boundary pinning effect. The aging treatment resulted in the formation of MgZn' precipitates in the α-Mg matrix of the alloys. These precipitates were more uniformly distributed in the Ca-added alloys than in the alloys without Ca. Thus, the heat treatment-induced precipitation improved the tensile and creep properties of the T6-treated alloys. The T6-treated ZWK611+0.7Ca alloy exhibited the best mechanical properties at room temperature and 150 °C among all the tested alloys. [ABSTRACT FROM AUTHOR]

• Based on the SDC-IC standard, a integral analysis of thermal mechanical properties was conducted using a combination of elastic and plastic analysis methods • In ductile damage analysis, local plastic yielding occurs in the inner tube, but the overall load-bearing performance of the structure is good. • In non-ductile damage analysis, the T-tube unit have the immediate plastic flow localization, but there is no the immediate local fracture due to exhaustion. • From the perspective of transient cyclic thermal hydraulic analysis, the results show that there will be no ratcheting. To verify the mechanical properties of the helium-cooled T-tube divertor, based on the thermal hydraulic optimization of the T-tube divertor, a preliminary analysis was conducted through a combination of elastic and elasto-plastic analysis. The results show that for the M-type damage mode, the T-tube divertor exhibits a small-scale plastic yielding phenomenon, but this has no effect on the overall divertor. The T-tube divertor has local necking deformation but does not fail due to immediate local fracture, and the T-tube divertor has no creep rupture. For the C-type damage mode, the plastic strain of the T-tube divertor is not accumulated under cyclic loading, but in the fatigue analysis, the life of the divertor does not meet the design standards and further optimization is needed. The conclusion shows that the optimized helium-cooled T-tube divertor has good thermo-mechanical properties, and the safety of the helium-cooled T-tube divertor unit can be guaranteed. [ABSTRACT FROM AUTHOR]

In contemporary developments across automotive, aerospace, and military industries, there is an ever-growing demand for lightweight and robust polymer composites. In this study, a ductile epoxy resin, carbon nanotubes (CNTs), cellulose nanofibers (CNFs), and silica nanoparticles were used to fabricate nano-fillers/epoxy composites and nano-fillers/silk fibers/epoxy hybrid composites through solution casting and hot pressing. Their mechanical properties and thermal characteristics were analyzed and compared, which show that: these nano-fillers can dramatically enhance the strength and stiffness of the ductile epoxy resin; however, this is achieved at the expense of its toughness and extensibility. CNT/silk fiber/epoxy hybrid composite has the highest tensile strength (81.10 MPa), Young's modulus (3.76 GPa) and impact strength (103.7 kJ/m2), while the CNFs-reinforced one exhibits the highest breaking energy (9.96 MJ/m3). These nano-fillers almost do not affect the thermal stability of the epoxy resin and silk fiber composites. In addition, the fracture modes of their reinforced composites were revealed by macroscopic and microscopic observations. • Reveal how different nano-fillers affect the mechanical behaviors of ductile polymer matrix. • Explore the optimal content of these nano-fillers in the polymer matrix. • Indicate nano-fillers do not affect the thermal stability of their reinforced composites. • Elucidate the composites' fracture modes introduced by silk fibers and different nano-fillers. [ABSTRACT FROM AUTHOR]

The development of high-power and small-sized electronic components requires the emergence of heat management materials with high heat flux. Hence, Ti-containing filler was used to braze graphite film/Cu high heat flux composites. The microstructure and forming mechanism of joints were studied, the influence of temperature on joint formation was analyzed, and the influence of graphite volume fraction on the thermal properties of the composites were discussed. The results show that the main microstructure of graphite/copper joints are Cu(s,s), Ti 6 Sn 5 and CuTi 2. As the brazing temperature increases, the carbide layer (TiC) that affects the connection gradually thickens, from <0.5 μm at 800 °C to 3 μm at 850 °C, which deeply improve heat transfer of composite materials. The tensile properties of composites also increase with increasing temperature, maximum tensile strength 31.94 MPa can be obtained at 850 °C. Furthermore, the composites are proved to possess high heat flux during process of heat transfer, and the transfer rate was 1.77 times that of Cu, 3.72 times of Al. The temperature rise test carry out in hot bench intuitively demonstrating that the composites have faster heating rate. Al used 197 s to raise from 25 °C to 50.5 °C, Cu used 140 s, while 76.92 % graphite-contained composites only took 75 s in the same volume and experimental condition. [Display omitted] [ABSTRACT FROM AUTHOR]

Glass system, with the following chemical composition xCuO∙(100-x)PbO 2 where x = 0, 5, 8, 10, 15, 20 mol% CuO, was successfully prepared using the melt-quenching technique. X-ray diffraction pattern indicated the amorphous structure for all samples. Density and molar volume were determined to evaluate the physical properties of the glasses. The evolution of the endothermic and exothermic process as CuO function was investigated by thermal analyses. The structural modifications induced by the incorporation of CuO in the lead host network were investigated by Fourier Transform Infrared, Raman, Ultraviolet-Visible and Electron paramagnetic resonance. The obtained results depicted the incorporation of Cu2+ ion enhances thermal stability and glass-forming ability of the lead glass. Furthermore, X-ray diffraction, Scanning electron microscopy and energy dispersive X-ray analysis confirm high solubility of MoO 3 in copper-lead host matrix. It was found that copper-lead dioxide host matrix is a suitable as waste form for radioactive waste management applications to improve the solubility of MoO 3 in glass. • Novel heavy metal oxide (HMO) glass composition for nuclear waste management applications. • xCuO∙(100-x)PbO 2 where x = 0, 5, 8, 10, 15, 20 mol% CuO system was synthesized by melt-quenching method. • FTIR spectra exhibit the coexistence of the basic structural units of lead [PbOn] and [CuO n ]. • UV–VIS absorption bands and EPR spectra indicated the presence of isolate Cu2+ ions. • High solubility of MoO 3 in copper-lead glass, without any phase separation. [ABSTRACT FROM AUTHOR]

A new series of cobalt-based perovskite (Gd 0.6 Sr 0.4) 0.99 Fe 1-x Co x O 3-δ (GSFC-x, x = 0.00, 0.05, 0.10, 0.15, 0.20 and 0.25) cathodes to aid in the development of intermediate temperature solid oxide fuel cells are reported. All the perovskites showed the coexistence of cubic and orthorhombic phases. To determine their suitability, the thermal properties dependence on the cobalt content were investigated via dilatometry, thermogravimetry and differential scanning calorimetry. GSFC-x exhibited the promising activity of the oxygen reduction reaction and ion transport from a comparable study. The thermal expansion coefficient of rich-cobalt samples showed a more compatible value to the common electrolyte than other similar cathodes. By varying Co doping, compromises were made between thermal expansion and electrical conductivity. Furthermore, phase stability was observed. [ABSTRACT FROM AUTHOR]

To further investigate the reinforcing factors on the adhesion strength of SiO 2 and TiB 2 modified SiBCN-based adhesives, the thermal stability analysis, microstructure observations and phase composition analysis were performed on four kinds of modified PSNB (Polyborosilazane) adhesives. With the different Si/B ratio and SiO 2 content, the room temperature adhesion strength reach up to 18.95, 12.04, 32.44 and 13.69 MPa for PPT-1, PPT-2, PPTS and PST respectively, after synthesized at 1000 °C in air. And then, the high temperature adhesion strength reach up to 12.3 and 16.4 MPa for PPT-1 and PPTS at 1000 °C in vacuum, respectively. Interestingly, it has been found that temperature, PSO, solid content and SiO 2 content all have a great influence on the adhesion performance of SiO 2 and TiB 2 modified SiBCN-based adhesives. [ABSTRACT FROM AUTHOR]

The application of boron in fuel-rich solid propellant is limited by its long combustion time, ignition delay and low combustion efficiency. To overcome these problems, B/Nitrocellulose (NC)/Fe particles were fabricated by electrospraying. The reactivity and combustion behavior of B/NC/Fe particles were characterized by TG/DSC, oxygen bomb calorimeter and laser ignition. Compared with pure boron, lower oxidation temperature was observed in the thermal analysis of prepared particles. Meanwhile, the prepared particles released more heat and ignite more readily during the combustion. Furthermore, B/NC/Fe particles were added into Hydroxyl-terminated polybutadiene (HTPB)/Ammonium perchlorate (AP) propellants as additives to test their combustion performance. The burning rate of propellants in air and closed bomb were both improved by 8.20% and 117%, respectively. Overall, B/NC/Fe particles not only show the superior reaction performance, but also contribute to the tunable burning rate of propellants. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of novel statistical copolymers of isocyanates. • Synthesis of novel block copolymers of isocyanates. • Improvement of the thermal stability of polyisocyanates. • Mechanism of thermal decomposition of polyisocyanates. • Effect of macromolecular architecture on the thermal stability of polyisocyanates. The synthesis of statistical and block copolymers of n-hexyl isocyanate (HIC) and 2–phenylethyl isocyanate (PEIC), via coordination polymerization using a half-titanocene complex, was studied. The complex [CpTiCl 2 (O-(S)-2-Bu)] was employed as initiator of all the polymerization reactions. The homopolymerization of PEIC was initially attempted under various experimental conditions. The statistical copolymers were synthesized in different proportions of the two monomer units, and their reactivity ratios were estimated using the Fineman-Ross, inverted Fineman-Ross, Kelen-Tüdos and extended Kelen-Tüdos graphical methods, along with the computer program COPOINT. Structural parameters of the copolymers were obtained by calculating the dyad sequence fractions of the monomers and their mean sequence lengths. Furthermore, a systematic and detailed investigation was performed on the thermal degradation of the copolymers compared with the respective homopolymers, by Thermogravimetric Analysis, TGA, and Differential Thermogravimetry, DTG, within the framework of the Ozawa-Flynn-Wall and Kissinger-Akahira-Sunose methodologies. It was concluded that the thermal stability of the copolymers was affected by the ratio of the two monomers in their structure and was increased with the addition of PEIC monomers. Additionally, the mathematical model of the mechanism through which the thermal decomposition of the homopolymer PPEIC takes place, was further investigated. Block copolymers PHIC-b-PPEIC were also synthesized via the same coordination polymerization approach and sequential addition of monomers starting from the polymerization of HIC. The samples were characterized by Size Exclusion Chromatography, SEC, and NMR spectroscopy. Their thermal decomposition profiles were studied by TGA and DTG measurements and were compared with the corresponding statistical copolymers. [ABSTRACT FROM AUTHOR]

A flame retardation property of polymer composites is being considered important to minimize the amount of heat release and the smoke production during the combustion. Therefore, this work aims to improve the flame retardation property of epoxy composites using ammonium polyphosphate (APP), one of the intumescent flame retardants (IFRs). However, APP could be migrated to the surface of composite due to the weak compatibility with epoxy resin. To prevent the migration, the surface modification method has taken place using various amines, acting as charring agent. In this study, we select the 4,4′-diaminodiphenylmethane (DDM) as both curing agent and charring agent for the surface modification on the APP, and their epoxy composites were prepared. Interestingly, we observe both the fast curing effect by analyzing the curing behavior of epoxy composite by Friedman method, and significant improvements of the thermal degradation, and flame retardancy of epoxy with adding the amine-modified APP (mAPP). Moreover, the epoxy/mAPP composites showed higher flame retardation properties and formed the compact char structures due to the attached DDM, which acted as an efficient charring agent to promote to form the carbonaceous char structures. Finally, we also found the correlation between the improvements of flame retardation properties, and char structures of epoxy composites by calculating the crosslink density (M c) using the theory of rubber elasticity. • Amine-modified ammonium polyphosphate was prepared via cationic ion exchange reaction with 4,4′-diaminodiphenylmethane. • The attached DDM can contribute to accelerate the curing and improve the flame retardation properties of epoxy composites.. • The relationship of flame retardation properties and char structure was found using theory of rubber elasticity. [ABSTRACT FROM AUTHOR]

Sensitivity analysis of Molecular Dynamics (MD) simulations has revealed that the predictions can be sensitive to the small perturbations in Interatomic Potential (IP) parameters. In order to make MD predictions for complex material systems more reliable, we performed uncertainty quantification of a high dimensional IP based on the Embedded Atom Method (EAM), a commonly utilized IP for metallic systems. The major contribution of this work is the prediction of a robust posterior probability distribution of the IP parameters by considering variations in the experimental values of various mechanical and thermal properties of FCC Al. The posterior probability distributions of the IP parameters were obtained using a Bayesian statistical framework. Reliability of potential parameters was assessed by performing MD simulations for a range of mechanical and thermal properties, using perturbed potential parameters. A comparison of the computed properties to existing experimental and first-principles data revealed that higher order properties such as grain boundary formation energy are sensitive (with variance of the order 10 5 ) to 1% perturbations. Using a Gaussian likelihood function, a posterior probability distribution of the IP parameters that minimizes the discrepancy between MD prediction and experimental values for various mechanical properties was obtained. Final properties of interest computed using this new distribution showed less sensitivity to changes in the IP parameters. Furthermore, the obtained posterior probability distribution reflects the uncertainty due to IP parameters and the quality of MD predictions is improved by propagating that uncertainty to the final properties. Thus, instead of obtaining point valued predictions from MD, probability distributions of the final properties are obtained using this framework. [ABSTRACT FROM AUTHOR]

Abstract The thermal stability of organic-inorganic nano-composites prepared by a two-stage polymerization of urea-formaldehyde resin (UF) with furfuryl alcohol (FA) and TiO 2 before and after irradiation has been researched. The two resins of urea-formaldehyde–TiO 2 composites, named: UF/TiO 2 and UF/TiO 2 /FA, were synthesized. The thermal stability of obtained materials was studied by non-isothermal thermo-gravimetric analysis (TG), differential thermal gravimetry (DTG) and differential thermal analysis (DTA). UF hybrid composites have been irradiated (50 kGy) and after that their radiation stability was evaluated on the basis of thermal behavior. The free formaldehyde (HCOH) percentage in all prepared samples was determined. The minimum percentage values of free formaldehyde (0.04% and 0.03%) for UF/TiO 2 and UF/TiO 2 /FA, respectively, after irradiation dose of 50 kGy are detected. The shift of temperature values for selected mass losses (T 10 %) to a high temperature indicates the increase in thermal stability of samples based on UF resin modified with FA. [ABSTRACT FROM AUTHOR]

Abstract How to effectively enhance the flame retardancy of polyamide 46/polyphenylene oxide (PA46/PPO) alloy is one of the key issues needed to be addressed. In this work, organic-modified zirconium phosphate (OZrP) nanosheet was incorporated with PU-coated carbon fiber (CF) to flame-retard PA46/PPO alloy. The combination of OZrP and CF showed an outstanding combination effect in improving the flame retardancy and thermal stability of PA46/PPO. With the incorporation of 2 wt% OZrP and 20 wt% CF, the peak heat release rate and peak smoke production rate of PA46/PPO were reduced by 65.6% and 86.2%, respectively. Besides, the T i (temperature at 5% weight loss) and the residue of PA46/PPO/OZrP/CF were increased by 13.2 °C and 20.9 wt%, respectively, compared with PA46/PPO. The flame-retardant mechanism was further studied and revealed: when being burned, CF acted as the skeleton to improve the strength of char; simultaneously, OZrP catalyzed the carbonization of the polymer chains on the CF surface to form a strong and compact protective char layer, which blocked the transmission of heat and combustible gases, thus effectively improved the flame retardancy of the composite. Highlights • An efficient strategy simultaneously improving the flame retardancy and mechanical properties of PA46/PPO alloy was proposed. • The synergistic mechanism of OZrP nanosheet and PU-coated carbon fiber (CF) on the flame retardancy of PA46/PPO was revealed. • OZrP catalyzed the carbonization of the polymer chains on the CF surface to form a strong and compact protective char layer. [ABSTRACT FROM AUTHOR]

Abstract Controlling and adjusting the thermal properties of a compound to improve the additive manufacturing process of a polymer matrix through selective laser sintering is of key importance to achieve an optimized final part density as well as hardness. In the past, the purpose of adding mineral fillers to polymers was primarily one of cost reduction. Today, however, fillers are more often used to fulfil a functional role, such as improved thermal or mechanical properties of the polymer composite [ 1 ]. In this study, the influence of calcium carbonate as a mineral filler particle on the thermal properties in compression-molded polyamide 12 was investigated. The particle size distribution and the filler amount within the polyamide 12 matrix were varied. The melt viscosity at 190 °C, the melting speed, melting and crystallization point as well as crystallization time at 170 and 172 °C were analyzed. A relationship between these properties and the implementation of a specific amount of calcium carbonate with a certain particle size distribution was observed. The study concludes, that the thermal and flow properties of a polyamide 12 matrix can potentially be manipulated to improve a laser thermal sintering process insofar as the layer melt can be optimized as well as the crystallization process speeded up. [ABSTRACT FROM AUTHOR]

Abstract The dimensional stability and dynamic mechanical properties on bamboo (non woven mat)/kenaf (woven mat) hybrid composites was carried out in this study. The hybridization effect of bamboo (B) and kenaf (K) fibers at different weight ratio were studied at B:K:70:30, and B:K:30:70 while maintaining total fiber loading of 40% by weight. The coefficient of thermal expansion (CTE) and dynamic mechanical properties of composites were analyzed by thermomechanical anlayzer (TMA), and dynamic mechanical analyzer (DMA), respectively. Positive hybridization effects were observed on B:K:50:50 hybrid composite with lowest CTE and highest dynamic mechanical properties among all composites. The dimensional stability were strongly influence by the fiber orientation where all composites shows prominent expansion in the transverse fibers direction but relatively low expansion in longitudinal fibers direction. Dynamic mechanical properties in term of complex modulus (E*), storage modulus (E′), loss modulus (E″), Tan delta and Cole-Cole plot were studied. DMA results reveal that B:K:50:50 hybrid composite possess the highest complex modulus due to the strong fiber/matrix interfacial bonding which supported by the coefficient of effectiveness and Cole-Cole plot. Hence, it is concluded that 50:50 weight ratio of bamboo and kenaf fibers is the optimum mixing ratio to enhance both dimensional and dynamic mechanical properties of hybrid composites, and it can be utilized for automotive or building materials applications which demand high dimensional stability and dynamic mechanical properties. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Abstract The hindered phenol antioxidant (HP) was grafted onto graphene oxide (GO) surface, and polyamide 6 (PA6)/GO-HP nano-composite was manufactured via melt processing. More efficient grafting of PA6 molecules onto GO surface was realized by forming hydrogen bonding, and GO was exfoliated and uniformly distributed in matrix. Compared with PA6/HP and PA6/GO, the oxidation induction time, thermal degradation temperature and E a of PA6/GO-HP composite increased significantly, retention of reduced viscosity and tensile strength were improved, revealing GO-HP hybrid was more efficient than HP or GO to resist thermal oxidation degradation of PA6. Such synergistic thermal oxidative stabilization mechanism was further revealed. Highlights • GO-HP hybrid was prepared by grafting hindered phenol antioxidant onto GO surface. • PA6/GO-HP nano-composite was manufactured via melt processing. • Exfoliated GO with high graft of PA6 uniformly dispersed in PA6 in presence of HP. • Synergistic thermal oxidative stabilization effect of GO-HP on PA6 was achieved. [ABSTRACT FROM AUTHOR]

Abstract The effect of Y 2 O 3 on the glass transition kinetics, crystallization kinetics, phase separation and crystallization behavior of 60ZnO–30B 2 O 3 –10SiO 2 glass has been investigated by non-isothermal differential thermal analysis, scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). The glass transition activation energies E g calculated by using both Kissinger and Moynihan model decrease from 668 kJ/mol to 573 kJ/mol for Kissinger model, and 682 kJ/mol to 587 kJ/mol for Moynihan model with the increase of yttrium oxide doping content from 0 to 6 mol%. And the glass crystallization kinetics parameters, crystallization activation energy E c and Avrami exponent n stands for crystal growth, are also obtained on the basis of several well developed equations. Increase of about 58 kJ/mol in Ec values obtained by different theoretical equations is caused by addition of 6 mol% yttrium oxide into 60ZnO–30B 2 O 3 –10SiO 2 glass, and the Avrami exponent (n close to 2) suggests that crystal growth in 60ZnO–30B 2 O 3 –10SiO 2 glass doped with or without yttrium is mainly one-dimensional growth of crystals. The results on the phase separation and crystallization behavior occurred at 893 K and 993 K respectively for base and doped glass, are well consistent with the glass transition and crystallization kinetics results. Hence, addition of yttrium oxide into 60ZnO–30B 2 O 3 –10SiO 2 glass decrease the glass transition activation energy while increase the crystallization activation energy of glass, thereby the stability of glass structure is improved. Phase separation phenomenon and crystallization behavior occurred at glass surface provide some useful information for preparing glass ceramics with micro- or nano-crystals in surface. [ABSTRACT FROM AUTHOR]

Abstract The phase diagram of the CaO–Nb 2 O 5 system was constructed on the basis of comprehensive experimental investigations using X-ray powder diffraction (XRD), thermal analysis (DSC/TGA), pyrometric observations, microscopic observations (SEM/EDS) and IR spectroscopy in the whole composition range up to 1600 °C. Thermal stability and structure of the phases reported in the literature have been compiled, critically evaluated and compared with the established data. To clarify the literature inconsistency regarding the nominal composition of the Ca 3 Nb 2 O 8 phase and the character of its melting, as well as the composition range and existence of the Ca 4 Nb 2 O 9 -based solid solution, detailed research on CaO-rich samples was carried out. The careful analysis of the literature data and our experimental results lead to a new version of the phase diagram. The CaO–Nb 2 O 5 system includes four intermediate compounds. Two of them, CaNb 2 O 6 and Ca 2 Nb 2 O 7 , melt congruently and the third, Ca 3 Nb 2 O 8 , decomposes in the solid state at 1540 ± 10 °C. No solid solutions were observed under the conditions of our study. [ABSTRACT FROM AUTHOR]

Abstract Thermal stability of calcium copper titanate was studied by differential scanning calorimetry, thermogravimetry and high-temperature mass spectrometry. Calcium copper titanate (CCTO) had no thermal effects and mass losses caused by thermal dissociation or any phase transitions, besides melting, in the temperature range of 298–1423 K. The melting point of calcium copper titanate is 1398 K. The endothermic effect at 1250 K was associated with the decomposition of copper (II) oxide segregated in the intergrain space of the CaCu 3 Ti 4 O 12 -CuO ceramics. In this connection, we proposed a simple method for estimating the content of copper oxide in the CaCu 3 Ti 4 O 12 -CuO composite. The processes of evaporation of CaCu 3 Ti 4 O 12 in the temperature range of 1500–2100 K were studied by high-temperature mass spectrometry. In the temperature range of 1500–1750 K, easily volatilized copper oxide was evaporated selectively from the calcium copper titanate. At the temperature of 2100 K, atomic calcium and titanium oxides, TiO and TiO 2 , were present in the vapor. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract The aim of this study was to determine thermal properties of pseudoplastic polysaccharides (guar gum, κ -carrageenan and xanthan gum) which find many applications as food hydrocolloids in food industry. There was an obvious relationship between thermal dependency of heats of fusion of hydrocolloids in powder form and activation parameters of hydrodynamic flow in solutions, respectively. Results of thermal analysis confirmed, that powder samples of hydrocolloids as typical foodstuffs of low moisture content less than 15 w% after room conditioning, exhibited varying ability to bind water as depending on their molecular structure. The peak temperature of the endothermic polysaccharide order-disorder phase transition process was found in the temperature range of 50–85 °C. It was influenced simultaneously by the applied heating rate and the samples moisture content. Studied samples moisture content was ranging between 9–40 w.% as was obtained after different conditioning. Observed reaction enthalpy ( ΔH ) associated with phase transition and water evaporation (proved by appropriate weight loss of the samples Δm w ) was ranging from 140 to 670 J/g. Activation energy ( E a ) of this process in powder samples was calculated from the kinetic parameters using three kinetic models developed by Friedman, Kissinger and model-free kinetics. The latter kinetic models were compared with the Arrhenius model, which was used to determine E a of polysaccharide solutions on reflecting sensitivity of their molecular structure to the temperature and the solvent. According to the Arrhenius model, there were obtained the highest values of E a for κ -carrageenan solutions, indicating the highest resistance of their molecular structure to temperature. This fact can be related to the observed the lowest value of the reaction enthalpy in the case of powder samples, suggesting that energy obtained during the order-disorder transition to change the carrageenan powder structure is limited. On the other hand, xanthan gum was the least temperature dependent sample; activation energy of xanthan solutions was only in the range of 2–6 kJ/mol. Concurrently, ΔH of xanthan powder was determined as the largest of all samples under study. In general, there was found an indirect relationship between activation energy of the solutions determined by viscometry and reaction enthalpy of the powders determined by thermal analysis. Results of the Arrhenius model also indicate that the energy necessary to promote viscous flow of solutions is higher for hydrocolloids in distilled water rather than in 0.07 M KCl aqueous solutions, suggesting the suppression of the polyelectrolyte effect. In both cases, E a was substantially reduced by application of higher shear rate. [ABSTRACT FROM AUTHOR]

An overcharge model of lithium ion battery pack was built by coupling the electrochemical model with thermal abuse model. The pack consists of three fully-charged batteries, each of which has a capacity of 10 Ah, using Li[Ni 1/3 Co 1/3 Mn 1/3 ]O 2 as the positive electrode. The three batteries in the pack were juxtaposed, and only the middle one was overcharged. The influences of current, convection coefficient and gap between batteries on the thermal runaway propagation were studied. The results of temperature and voltage obtained from the models were validated experimentally, and they were agreed well with the experimental data with the relative error within 6%. The results showed that the onset temperature of thermal runaway of the charged battery increased with an increase in the current, while the temperatures for the other two decreased. The temperature rate of the charged battery changed little when the convection coefficient was greater than 40 W/m 2  K. The clamp of lithium ion battery pack had an important effect on the thermal runaway propagation. The occurrence of thermal runaway propagation was depended on whether there was the existence of clamp when the battery gap exceeded 5 mm. [ABSTRACT FROM AUTHOR]

Ceramicizable phenolic resin matrix composites are widely used in aerospace fields, and their heat resistance rating can reach 1400 °C. To further improve heat resistance, HfB 2 -SiB 6 ceramicizable phenolic resin matrix composites were prepared, and their thermal properties and oxidative corrosion behaviour were studied. The results showed that the composites with 30 % SiB 6 had a ceramic yield of 69.69 % at 1600 °C, and their linear and mass ablation rates were as low as 0.004 mm/s and 0.043 g/s, respectively. XRD and thermodynamic calculation showed that there were complex reactions to form Hf ceramics and Si-B-N-O to prevent corrosion under high temperatures of about 2000–2400 °C. • HfB 2 -SiB 6 improves the heat resistance of ceramicizable phenolic resin composites. • Composites' linear and mass ablation rates are as low as 0.004 mm/s and 0.043 g/s. • The composites with 30 % SiB 6 have 69.69 % ceramic yield after 1600 °C treatment. • Complex reactions occur to form Hf ceramics and Si-B-N-O preventing corrosion. • Composites have heat resistance at 1600 °C and ablation resistance at 2000–2400 °C. [ABSTRACT FROM AUTHOR]

This paper presents silver/poly(vinyl alcohol) (Ag/PVA) and silver/poly(vinyl alcohol)/graphene (Ag/PVA/Gr) composites prepared by the immobilization of silver nanoparticles (AgNPs) in PVA and PVA/Gr hydrogel discs previously cross linked by the freezing/thawing method. The AgNPs inside the hydrogel matrices were synthesized following an innovative in situ method of electrochemical reduction of Ag + ions within PVA and PVA/Gr hydrogel discs. In addition, the novel materials introduced here were characterized by UV–visible spectroscopy, cyclic voltammetry, Raman spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, silver release measurements, and thermogravimetric analysis. The effective immobilization of the AgNPs inside the PVA and PVA/Gr hydrogel networks was achieved by their bonding with the exposed hydroxyl groups in PVA. Also, the incorporation of graphene into the PVA matrix and the bonding between PVA molecules and incorporated graphene sheets improves thermal stability of Ag/PVA/Gr and prevents aggregation and growth of AgNPs as observed by Fourier transform infrared spectroscopy and field emission scanning electron microscopy. [ABSTRACT FROM AUTHOR]

• Oscillatory thermal response tests can determine ground thermal properties with high accuracy • Testing duration is reduced compared to traditional in situ thermal response tests • Fitting with analytical model provides accuracy comparable to numerical simulations In situ subsurface thermal conductivity (λ) and thermal diffusivity (α) are critical parameters to design ground-coupled heat pump systems (GCHP). λ is conventionally determined from thermal response tests (TRT), whereas α is commonly selected from literature data or with laboratory analyses. Alternatively, both thermal properties can be assessed independently with an oscillatory thermal response test (O-TRT), which consists of heating the subsurface at an oscillatory rate and monitoring the resulting thermal perturbation. Due to their flexibility and relatively small radius, heating cables can be used to carry out tests in shallow unconsolidated deposits in the scope of horizontal GCHP design. The duration of the tests is short compared to vertical ground heat exchangers (fractions of a day) since the thermal resistance between the heating cable and the soil is negligible. The objective of this work was to develop an apparatus and an analytical approach to assess λ and α from an O-TRT carried out in shallow unconsolidated deposits. Nine different O-TRTs were performed in the lab for a dry standard material and five O-TRTs were performed in situ in a natural sandy deposit. After validation via numerical modelling, results show that the analytical approach using correction factors allowed the estimation of λ and α with an accuracy of < 2%. The study demonstrates that O-TRTs are a useful method to estimate both λ and α. Further testing in other reference materials and with different apparatus configurations is needed to enhance the experimental setup and extend O-TRTs towards new applications. [ABSTRACT FROM AUTHOR]

A novel series of transition metal complexes of Cu(II), Co(II), Ni(II), Mn(II) and Cd(II) were prepared from Schiff base derived from 4-aminoantipyrine and quinoline-2-carbaldehyde to give 4-((quinolin-2-yl)methyleneamino)-1,2-dihydro-2,3-dimethyl-1-phenylpyrazol-5-one (QMP). The structural features were derived from elemental analysis, mass spectroscopy, X-ray, IR, 1 H NMR, electronic spectra, molar conductance magnetic susceptibility and thermogravimetric studies. On the basis of the studies the coordination sites were proven to be through oxygen of the ring C O and nitrogen of the azomethine (HC N) group. The thermodynamic parameters were calculated using Coats–Redfern and Horowitz–Metzger methods. From the values of the thermal activation energy of decomposition (E a ) of Schiff base (QMP) and its metal complexes ( 1–5 ), it was found that the E a value for the complex ( 3 ) is higher compared to the other complexes. The Gibbs free energy of decomposition (ΔG ⁎ ) for Schiff base (QMP) and its metal complexes is positive value which indicates that the processes are non-spontaneous. The interaction between Schiff base (QMP) and its metal complexes and calf thymus DNA shows hypochromism effect coupled with obvious bathochromic shift. From the values of binding constant (K b ) we noted that the highest value of K b is belong complex ( 3 ) and these indicated that the Ni(II) is highly binding with CT-DNA and these due to the lower ionic radius. Furthermore, quantum chemical parameters of Schiff base and its complexes were calculated and discussed. The antimicrobial activity of Schiff base (QMP) and its M(II) complexes were studied and compared with the standard antibacterial and antifungal drugs. [ABSTRACT FROM AUTHOR]

Different nano- and micro-fillers are added to modify the mechanical properties, wear resistance, thermal properties and the curing process of polymers. A very important application for epoxy resins is to be used as coating for anti-cavitation painting. Pyrogenic silica is already used in adhesives and paints, being its application related to rheology. The objective of this work is to study the effect of pyrogenic silica on epoxy resins, usually not present in their formulation. SiO 2 /epoxy nanocomposites with two different loads of nano-silica, 3 and 5 wt% were manufactured. In particular, the study focuses on the influence that the addition of nano-silica has on the mechanical, wear and cavitation erosion properties as well as on the thermal properties and the curing reaction. To accomplish these goals, nanocomposite samples in bulk and as coating were prepared. Mechanical properties (hardness, bending and tensile strength), wear resistance (in bulk and coating) and cavitation erosion were evaluated. The epoxy curing process and the influence of nano-SiO 2 additions on the glass transition temperature ( T g ) were studied by Differential Scanning Calorimetry (DSC). In general, a plasticising effect was observed with nano-silica addition. Moreover, the resistance to erosion by cavitation, in terms of cumulative erosion and erosion rate, was higher for the nanocomposites than for clear resin. [ABSTRACT FROM AUTHOR]

In the present work, we developed industrially scalable and affordable Ketjen carbon black (K-CB)-ethylene methyl acrylate copolymer (EMA) composites with low percolation threshold and efficient electromagnetic interference (EMI) shielding efficiency associated with high potential of absorption dominance of electromagnetic (EM) radiations by conductive dissipation. The dispersion and distribution of K-CB inside the EMA elastomer have been affirmed with the help of qualitative electron micrograph techniques. The EMA matrix and K-CB filler interactions have been corroborated through bound rubber content and dynamic mechanical properties. Interfacial interactions between K-CB and polymer matrix are pivotal in determining the good reinforcing efficiency with tunable electrical conductivity as well as adjustable EMI shielding ability in K-CB filled composites. The proposed composites lead to a low percolation threshold (8.6 wt%) and promising high EMI shielding value of 33.9 dB for 20 wt% K-CB in the X-band frequency as compared to other expensive carbon fillers. On account of the thorough analysis of the composites, our high hopes have been placed on the promotion of low budget and flexible EMA/K-CB composite for the emerging field of superior EMI shielding applications. [ABSTRACT FROM AUTHOR]

Double-layer cladding materials were fabricated by roll bonding using stainless steel (STS439) and aluminum (Al1050) sheets to investigate the thermal conduction of multi-layer composites. The measured thermal conductivities were compared to values calculated from cross-plane models that are widely used for resistor connections in electrical circuits. The measured thermal conductivity was 88.3 W/m·K for the sample containing 76 vol% of Al1050. Unexpectedly, the measured cross-plane thermal conductivities were always higher than the values calculated from the series model. The high cross-plane thermal conductivities were attributed to the contribution of phonons to thermal transfer. A deviation index of the thermal conductivity, F m(S) , is proposed, which effectively describes the cross-plane thermal conductivity characteristics of double-layer materials. [ABSTRACT FROM AUTHOR]

The effect of adding silica (SiO 2 ) to a mixed-salt solid acid composite, CsH 2 PO 4 /NaH 2 PO 4 , was studied via conductivity measurements, thermal analyses and X-ray diffraction. The conductivity value of the composites ranged from 1.1 × 10 −4 S cm −1 to 7.6 × 10 −3 S cm −1 for temperatures from 210 °C to 250 °C, respectively. Adding NaH 2 PO 4 to the composite reduced the conductivity value at 230 °C due to the decomposition of NaH 2 PO 4 , which initiated at 210 °C. Dehydration of CsH 2 PO 4 was evident at 230 °C and 270 °C, while the superprotonic phase transition was not observed. Dehydration was detected for NaH 2 PO 4 at temperatures above 210 °C, but a thermally stable composite was produced by mixing it with CsH 2 PO 4 and SiO 2 . An X-ray diffraction analysis confirmed the existence of solid acid solutions for the composites consisting of NaH 2 PO 4 :CsH 2 PO 4 and SiO 2 :CsH 2 PO 4 in molar ratios of 1:10 to 3:10. The presence of SiO 2 partially obstructed the dehydration of the composite, as the diffraction intensity of the dehydration by-product Cs 2 H 2 P 2 O 7 decreased at the end of the thermal treatment. [ABSTRACT FROM AUTHOR]

The application of black phosphorus (BP) nanosheets to improving the fire safety of polymers has been intensively explored in recent years. The phosphorus-rich construction, inherent layered structure, and ease of surface modification contribute to the highly efficient flame-retardant performance of BP nanosheets. Reported results confirmed that BP nanosheets and BP-based hybrids could reduce the release of heat, suppress fire spreading, and reduce the emission of smoke and toxic gases during the combustion of polymers. However, the poor air and moisture stability, severe synthesis conditions, and difficulty to scale up limit their wide application. Up to date, there is no review about BP-based flame retardants for improving the fire safety of polymer nanocomposites. In this review, we summarize the proposed, preparation approaches, surface modification methods and improved air stability, and flame-retardant mechanisms of BP nanosheets and flame-retardant BP nanosheets/polymer composites. The fire safety of polymer nanocomposites is discussed to specifically illustrate the functions of BP nanosheets. Lastly, the limitations and the outlook of using BP nanosheets as flame retardants are presented. [Display omitted] • Recent progress in BP for improving fire safety of polymers was summarized. • Surface modification methods of BP were reviewed. • Flame-retardant mechanisms of BP hybrids were discussed. • The application prospect of BP in flame retardant field was discussed. [ABSTRACT FROM AUTHOR]

The paper analyzes the effect of severe plastic deformation on the structure, mechanical and thermal properties as well as crystallization process of a Zr 62.5 Сu 22.5 Al 10 Fe 5 alloy. High pressure torsion (HPT) induces local atomic changes and accumulates the formation of inhomogeneous chemical regions. The mechanically treated alloy structure is generally complex. The residual glassy matrix contains nanocrystalline particles. The structural changes observed during the HPT process lead to significant changes in the crystallization process. The effect of shear strain on crystallization of the Zr 62.5 Сu 22.5 Al 10 Fe 5 alloy and its properties was studied in detail using transmission electron microscopy (TEM), X-Ray diffraction (XRD), and differential scanning calorimetry (DSC) methods. • HPT leads to the formation of an inhomogeneous amorphous structure. • High strain radically changes the process of thermal solidification of the alloy. • Inhomogeneous amorphous structure is the reason for the high increase in hardness. [ABSTRACT FROM AUTHOR]

Silica/phenolic composite materials are often used in thermal protection systems (TPS) for atmospheric re-entry. The present work aims to compare two different approaches to assess heat transfer properties of these materials: i) using standard and specific experimental methods, and ii) with the development of 3D thermal transfer multiscale model using 2D (microscopy) and 3D (tomography) images. The latter procedure, based on computations on images, is a two-step change of scale from microscopic scale to mesoscopic scale and then to the macroscopic one. Two silica/phenolic composites with different spatial organizations are studied and their thermal properties are compared. Several experimental methods have been used, including space-resolved diffusivity determinations. Numerical results are compared to experimental ones in terms of transverse and longitudinal thermal conductivities of the composites, and were found to be in good agreement. A discussion is made on the different possible sources of uncertainty for both methods. [ABSTRACT FROM AUTHOR]

In this study, organo-modified layered double hydroxides (LDH) as nanoparticleswere used to prepare hybrid nanocomposites based on polypropylene (PP), ethylene vinyl acetate copolymer (EVA) blend in presence of a maleated polypropylene (PP-g-MA) as compatibilizer via a one-step melt mixing process. Transmission electron microscope (TEM) was employed to determine localization of LDH nanoparticles in the blend nanocomposites. Microstructures of the nanocomposites were studied by means of scanning electron microscopy (SEM). Thermo-mechanical properties of nanocomposites were investigated by dynamic mechanical thermal analysis (DMTA). Differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA) were also used to investigate crystallization behavior and degradation process of the nanocomposites, respectively. The results showed that, LDH nanoparticles in the exfoliated and/or intercalated states were mainly localized in the EVA phase. The average particles size of EVA domains was reduced in presence of LDH and PP-g-MA. The storage modulus of nanocomposites was controlled by combination of LDH and PP-g-MA. The crystallization studies revealed that 5wt%LDH and PP-g-MA increased crystallization temperature to 133.4 °C while addition ofLDH in absence of the compatibilizer decreased the crystallization temperature to 122.7 °C.Investigation of thermal degradation behavior of samples indicated that presence of LDH and PP-g-MA in PP/EVA blendsimprovedinitial degradation temperature of nanocomposites by about 43% compared to the neat PP. [ABSTRACT FROM AUTHOR]

The thermal conduction properties of 2.5D angle-interlock woven composites (2.5DAWC) were investigated along warp, weft and thickness directions both from experimental measurement and finite element analyses (FEA). A self-designed apparatus was established to measure the thermal conductivity of 2.5DAWC. The multi-scale FEA models were selected from representative volume elements (RVE) of matrix, yarns and composites by detailed geometrical structural analyses. The micro-scale models including the matrix-voids RVE and the fiber-matrix RVE were used to calculate the thermal properties of resin matrix and yarns, respectively. The meso-scale model was created to analyze the overall thermal conduction behaviors of 2.5DAWC, including the temperature and heat flux distributions. The effects of voids and interface thermal contact resistance on the thermal conductivity were also considered and analyzed in this paper. The results from FEA showed reasonable agreement with the experimental with an error of less than 5%. The methodology of this paper could be applied to understand the thermal conduction behaviors of complicated structural composites, and also can be used to predict the coupled thermal-mechanical properties of composites. [ABSTRACT FROM AUTHOR]

The influence of the filler size and content on the crystallization behavior of polypropylene (PP) composites filled with three multi-walled carbon nanotubes (MWCNTs) with different sizes was investigated by means of a differential scanning calorimetry (DSC). It was found that the values of the onset crystallization temperature, crystallization peak temperature and end crystallization temperature increased with increasing MWCNT weight fraction and with decreasing filler average diameter; the value of the crystalline degree of the composites increased slightly with increasing filler weight fraction. The values of the crystalline degree of the composites filled with MWCNTs with wide length-diameter ratio and small specific surface area were the lowest when the MWCNT weight fraction was lower than 4%, which can be attributed to weak interaction between the matrix and inclusions due to small specific surface area. Moreover, the total crystallization rate of the composites filled with a small amount of the MWCNTs could be significantly increased. [ABSTRACT FROM AUTHOR]

[Display omitted] • Metal-free and air-tolerable insertion polymerization using sulfoxonium ylides as monomers. • Polythioethers with good thermal properties. • Insertion polymerization features mild condition, easy operation and broad substrate scope. Insertion polymerization represents a concise approach to construct carbon-heteroatom bonds in the main chain. Despite some momentous efforts have been devoted to transition-metal catalyzed insertion polymerization, the metal-free insertion polymerization remains elusive. Herein, the fascinating metal-free and air-tolerable insertion polymerization using sulfoxonium ylides as monomers has been disclosed, furnishing a plethora of polythioethers and aromatic polyamines with carbon-heteroatom bonds in the main chain (yield up to 99%, Mn up to 20100). The insertion polymerization features mild condition, easy operation and broad substrate scope. In addition, thermal analysis demonstrated the polymers exhibited good thermal properties. [ABSTRACT FROM AUTHOR]

The new results on the relationships between impact damage energy and thermal property variations in carbon and glass fiber reinforced plastics have been obtained on "dry" composite samples, as well as on the samples subjected to thermal cycling and moisture saturation. The estimates of impact damage detection limit are presented, and the impact energy ranges where variations of effusivity and diffusivity linearly depend on energy are obtained. The experiments on the samples subjected to long-term moisture saturation and thermal cycling revealed no significant influence of these impacts on thermal property. It is concluded that thermal nondestructive testing may serve as a reliable tool for estimating severity of impact damage in aircraft composite structures. [ABSTRACT FROM AUTHOR]

Tensile experiments of composite joints with bonded embedded steel plate were conducted at 25 °C. Based on the experiments, thermal and mechanical finite element models were developed to investigate thermal behavior and tensile properties of the joint under 25 °C, 50 °C and 100 °C. The effects of side adhesive thickness, material parameters variation and metal material were discussed. Results show that higher ambient temperature contributes to faster temperature transfer but lower tensile properties, and the effect of material parameters variation should be considered especially under elevated temperature. Compared with using 45 steel and Al-7075, the joint using TC4 possesses low thermal stress and high tensile strength. Thicker side adhesive contributes to larger failure load and structural stiffness in a certain range. [ABSTRACT FROM AUTHOR]

The efficiency of glass ceramic sealants plays a crucial role in high temperature applications' performance and durability, such as oxygen separation from air. In order to develop suitable sealants, operating at about 950 °C, several glass–ceramics with different compositional additives and ratios in BaO–Al 2 O 3 –SiO 2 system have been prepared and investigated. The effect of additive oxides (CaO, CoO, B 2 O 3 ) as network modifiers on the thermal and dielectric properties of BaO–Al 2 O 3 –SiO 2 glass–ceramic for further oxygen transport membrane (OTM) applications was evaluated and discussed. The introduction of additives has evident effects on the main crystalline phases and physical properties of the glass–ceramics. Among these systems, B 2 O 3 -rich BAS system (BABS) can be densified at the sintering temperature below 700 °C through viscous sintering. Also, BABS shows the lowest dilatometric softening temperature at 675 °C, which can be explained by a fast densification associated with shrinkage of 25%. After devitrification for 200 h at 950 °C, BABS exhibits excellent thermal stability, suffering a weight loss of maximum 0.04%. It has the highest conductivity and resistivity, a high dielectric constant of 67.8 and a loss of 0.029 at 10 MHz, which provide an attractive insulating feature for many technological applications. However, considering all other properties investigated besides the electric ones, only B 2 O 3 -rich BAS meets the requirements for use as a sealant for BSCF membrane. Low softening temperature of BABS opens more ways for adding additives to tailor its functional properties, which enables it to being used as sealant material for OTM applications. [ABSTRACT FROM AUTHOR]

The objective of this research was to investigate the effect of non-durable flame retardant (NDFR) coating of samples of polyester fabric untreated and treated with UV/Ozone for different periods. For this purpose, these samples were tested by Fourier transform infrared (FTIR) spectroscopy, thermal analysis tests as thermo-gravimetric analysis (TGA) and differential scanning calorimeter (DSC). The ignition test was applied using limiting oxygen index (LOI), flame chamber (UL/94). Results indicated that both AZ2 (dried at room temperature) and AZ8–12 (dried at 80 °C for 30 min after coating with non-durable fire retardant (NDFR) coating) polyester samples have significantly decreased the rate of burning and increased the limiting oxygen index. [ABSTRACT FROM AUTHOR]

The objective of this work was to prepare and characterize magnetic hydrogels based on iota-carrageenan, a polysaccharide obtained from biomass ( Rodophyceae algae), containing maghemite (γ-Fe 2 O 3 ) nanoparticles. The morphological, thermal and magnetic properties of the hydrogels were evaluated, as well as the influence of the crosslinking agent (CaCl 2 ) at different concentrations (0.3 mol L −1 and 0.5 mol L −1 ) on the hydrogels’ properties. The samples were characterized by scanning and transmission electron microscopy, vibrating sample magnetometry, thermogravimetry, Fourier-transform infrared spectroscopy and Mössbauer spectroscopy. The swelling degree of the hydrogels was also determined. The results showed that the synthesized magnetic material was mostly composed of γ-Fe 2 O 3 and presented ferrimagnetic behavior. The hydrogels had spherical morphology and particle size in the range of 710 μm. The TEM images proved the magnetic particles had nanometric size. The hydrogels had good thermal stability and swelling degree in water of around 55%. Both the magnetic nanoparticles and crosslinking agent (Ca 2+ ) were well distributed on the surface of the hydrogels. The samples responded to the stimulus of a magnet. [ABSTRACT FROM AUTHOR]

We investigated the thermal degradation characteristics of polylactide (PLA) aluminium diethylphosphinate (AlPi) composites involving SiO 2 , halloysite (HNT) and organically modified montmorillonite (OMMT) via direct pyrolysis mass spectrometry. Presence of nanoparticles, SiO 2 , HNT and OMMT affected both thermal stability and relative yields of thermal degradation products of PLA/AlPi. The trans-esterification reactions and interactions between PLA and AlPi were depressed in the presence of SiO 2 and HNT. The increase in thermal stability detected in the presence of OMMT was associated with generation of cross-linked structure as a consequence of reactions between the organic modifier of montmorillonite, the carbonyl groups of PLA and phosphinates. [ABSTRACT FROM AUTHOR]

Three polypropylene (PP) composites filled separately with different sizes of graphene nano-platelets (GNPs) were prepared using a melt blending method. Thermal gravimetric analysis of the samples was conducted to investigate the effects of the GNP size on the thermal decomposition behavior. Some probable thermal decomposition mechanism parameters were determined through the Malek method, and then the most probable thermal decomposition mechanism functions of these composite systems were obtained using the Achar and Coats–Redfern methods. The thermal decomposition kinetics equation with integral form of the thermal degradation mechanism function for these composites was g ( α ) = 1 − ( 1 − α ) 1 / 3 . The thermal degradation mechanism was a phase boundary controlled reaction (contracting volume). The calculated activation energies of the three composites were, respectively, 277.4, 283.1 and 300.5 kJ/mol. This indicated that the GNPs could improve the activation energy of PP composites, and the activation energy increased with increasing the GNP lateral dimension. Moreover, the thermal decomposition was simulated by applying the thermal decomposition kinetics equation and the determined function parameters; good agreement was found between the simulations and the experimental values. [ABSTRACT FROM AUTHOR]

PVDF/PMMA blend exhibits a complex DSC thermogram due to the presence of multiple crystalline phases. This paper shows that Raman and FTIR spectroscopies allow a better interpretation of the thermogram, especially when the sample is heated above the glass transition temperature leading to recrystallization. Use of vibrational spectroscopies, such as Raman and Fourier Transform Infrared (FTIR), during the heating of the polymer gives access to its thermal micro-structural evolution. By this approach, it was possible to discriminate the two crystalline phases initially present in the samples (α and β phases) from the global signal of the whole crystalline phase extracted from the DSC curves. Moreover, crystallization of a third phase (γ-phase) was evidenced using FTIR. Results clearly show that the γ crystallization is a phase transformation from both α- and β-phases. Further to these results, recrystallization and melting of each crystalline phase has been characterized precisely. [ABSTRACT FROM AUTHOR]

• A comparative analysis of Zn 1.88–2 x Mn 2 x Mg 0.12 SiO 4 and Zn 2–2 x Mn 2x SiO 4 was performed. • Lattice parameters of both solid solutions change nonmonotonically. • Melting points of solid solutions decrease with increasing manganese concentration. • The introduction of 6 at% magnesium reduces decay time by almost a factor of two. [Display omitted] The effect of magnesium introduction on the structural, thermal, and luminescent characteristics of Zn 2 SiO 4 :Mn at the fixed magnesium concentration of 6 at% has been studied. Zn 1.88–2 x Mn 2 x Mg 0.12 SiO 4 phosphors were synthesized by the solid phase method. The structural properties were studied using X-ray diffraction. The luminescent properties were characterized by the PLE and PL spectra. The charge state of manganese ions was determined by the XPS method. It was found that the Zn 1.88–2 x Mn 2 x Mg 0.12 SiO 4 samples at x ≤ 0.14 were single-phase. The unit cell parameters of the solid solutions changed nonmonotonically with increasing x. The change in the linear trend of the parameters occurred at x = 0.06, and was caused by the oxidation of a part of the Mn2+ ions to Mn3+. The introduction of 6 at% magnesium into the Zn 2–2x Mn 2x SiO 4 structure caused an inversion of the crystallographic positions in which manganese was predominantly oxidized. It was shown that the melting temperatures of the Zn 2–2x Mn 2x SiO 4 and Zn 1.88–2 x Mn 2 x Mg 0.12 SiO 4 solid solutions decreased with increasing manganese concentration, but were practically independent of the presence of magnesium. The structural phase transition α→β was recorded in the premelting region for all Zn 2–2 x Mn 2 x SiO 4 compositions. For the Zn 1.88–2 x Mn 2 x Mg 0.12 SiO 4 solid solutions, the α→β transition was registered only for x ˂0.06. The optimal photoluminescence intensity of Zn 2–2 x Mn 2 x SiO 4 shifted to the region of lower values of x with the introduction of magnesium and turned out to be maximum for Zn 1.76 Mn 0.12 Mg 0.12 SiO 4. The introduction of 6 at% magnesium reduced the decay time by almost a factor of two; for the sample with x = 0.06 the decay time was 0.654 ms. [ABSTRACT FROM AUTHOR]

This paper reports on the thermal analysis of blind-bolts connected to concrete filled steel tube (CFST) and hollow steel section (HSS) columns. The aim is therefore the investigation of the temperature distribution in the connected sections and the evaluation of the effects due to concrete filling and anchored bolt extension. For this purpose, experimental and numerical work was carried out. The test programme involved twelve small-scale unloaded specimens where the variables were: tube section dimensions, type of blind-bolt, and hollow or concrete filled steel tubes. Results from the experiments revealed the noteworthy effect of concrete on bolt temperature reduction, the insignificant influence of tube section dimensions, and the limited impact of embedded bolt extension. Finite element models (FEM) of connections were developed to simulate the behaviour of tested pieces. Comparison with tests allowed the calibration of thermal material properties and characteristics of heat flux in interactions. Furthermore, assessments of heat transfer problem on the simulation of small-scale pieces extended to the numerical model of the whole endplate connection between an I-beam and a tubular column. Finally, the suitability of simple methods from Eurocode 3 Part 1.2 and other references to obtain the temperature on the connection was evaluated. [ABSTRACT FROM AUTHOR]

N-doped carbon xerogels were prepared by ammonia assisted pyrolysis. The effect of pyrolysis in NH 3 containing atmosphere on the surface characteristics and the extent of nitrogen incorporation were assessed. The special attention was paid to the usage of a material as an adsorbent for removing Cu(II) and Pb(II) ions. Elemental analysis confirmed presence of N in the structure (∼6%). SEM and gas sorption analysis showed that the structure was not damaged during NH 3 pyrolysis, some texture parameters were even slightly improved (e.g. micropores surface area: 1831 and 2083 m 2 g −1 for non-doped and N-doped samples, respectively). Higher resistance against oxidation was confirmed for N-doped samples with decomposition between ∼500 and 700 °C. In contrast, N-doped xerogels exhibited loose of mass over 800 °C in inert, whereas the mass loss for non-doped samples was negligible during heating to 1300 °C. Moreover, thermoanalytical measurements revealed that N is responsible for higher hydrophilicity. Adsorption capacity for N-doped xerogels was enhanced 2–6× in comparison with non-doped variants and reached ∼0.30 mmol g −1 for Cu(II) and ∼0.25 mmol g −1 for Pb(II) ions. The complexation with N atoms was proposed as the main adsorption mechanism. Furthermore, the oxygen atoms play some complementary role in adsorption. [ABSTRACT FROM AUTHOR]