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The paper presents and discusses the results of a study of the thermal properties of cement composites with different contents of magnetite aggregate (0%, 20%, 40% and 60% by volume). The effect of grain size on the evaluated thermal properties was also investigated. For this purpose, concrete containing 50% by volume of magnetite aggregate with four different fractions (1–2 mm, 2–4 mm, 4–8 mm and 8–16 mm) was used. Thermal parameters were evaluated on specimens fully saturated with water and dried to a constant mass at 65 °C. The series with varying grain sizes of magnetite achieved thermal conductivity values in the range of 2.76–3.03 W/(m·K) and 2.00–2.21 W/(m·K) at full water saturation and after drying to a constant mass, respectively. In the case of the series with 20% magnetite by volume, the thermal conductivity was 2.65 W/(m·K) and 1.99 W/(m·K) for the material fully saturated with water and dried to a constant mass, respectively. The series with a 60% volume share of magnetite obtained values of this parameter of 3.47 W/(m·K) and 2.66 W/(m·K), respectively, under the same assumptions. [ABSTRACT FROM AUTHOR]

2,3-dihydro-5,6,7,8-tetranitro-1,4-benzodioxine (TNBD), molecular formula = C8H4N4O10, is a completely nitrated aromatic ring 1,4-benzodioxane derivative. The convenient method of TNBD synthesis was developed (yield = 81%). The detailed structure of this compound was investigated by X-ray crystallography. The results of the thermal analysis (TG) obtained with twice re-crystallized material revealed the onset at 240 °C (partial sublimation started) and melting at 286 °C. The investigated material degraded completely at 290–329 °C. The experimental density of 1.85 g/cm3 of TNBD was determined by X-ray crystallography. The spectral properties of TNBD (NMR, FT-IR and Raman) were explored. The detonation properties of TNBD calculated by the EXPLO 5 code were slightly superior in comparison to standard high-energy material—tetryl (detonation velocity of TNBD—7727 m/s; detonation pressure—278 kbar; and tetryl—7570 m/s and 226.4 kbar at 1.614 g/cm3, or 260 kbar at higher density at 1.71 g/cm3. The obtained preliminary results might suggest TNBD can be a potential thermostable high-energy and -density material (HEDM). [ABSTRACT FROM AUTHOR]

An extensive analysis on three distinct composite materials, namely Rattan Fiber Composite (RFC), Bamboo Fiber Composite (BFC), and Rattan/Bamboo Fiber Composite (RBFC), was conducted in this research. In scope of this investigation, water absorption (WA), swelling thickness (ST), density, thermogravimetric analysis (TGA), thermal conductivity, and fourier transform infrared spectroscopy (FTIR) of the composites were analyzed and studied. Density differences between composites are evident, with RBFC having the highest density due to its low water absorption and inherent hydrophobicity, while BFC, with its high-water absorption, exhibits the lowest density. With the increase of immersion time of the composite the WA increases. In case of salt solution, the WA is lower than the distilled water (DW). In case of ST, the BFC shows the maximum amount of ST. Overall, the maximum WA, ST, and density was 17.23%, 13.92 % and 1.12 gm/cm3 for BFC, BFC and RBFC respectively. The results of the Fourier Transform Infrared (FTIR) analysis provided evidence of the existence of hemicellulose, cellulose, lignin, and hydroxyl (-OH) groups in RBFC. RBFC shows maximum decomposition rate with 2.42 and 6.11 mg/min at 358 and 414 °C respectively. The maximum thermal conductivity was observed at RBFC with 0.266 W/m.K.

The properties of unconventional blends of crystallizable and thermo-cross-linkable polychloroprene (CR) with polybutadiene (BR) were investigated in this study. The compositions were prepared using the method of reactive processing and cross-linking in the presence of nano-sized zinc (nZn). The purpose of the research was to assess the efficacy of nano-zinc as a curing agent of polychloroprene and polybutadiene (CR/BR) composites and to obtain rubber goods characterized by increased flame resistance. The blends were filled with nano-silica (aerosil) and fillers of natural origin (chalcedonite or silitin). The cross-linking process was characterized by determining the kinetics curves, the equilibrium swelling, and the Mooney–Rivlin elasticity constants. The morphology of the vulcanizate surface was specified by scanning electron microscopy (SEM). The dynamic and mechanical properties, flammability, and toxicity of gaseous substances involved in thermal decomposition were determined. Mass changes and thermal effects were studied using simultaneous thermal analysis (STA). It was confirmed that nano-zinc is an efficient curing agent for the polychloroprene and polybutadiene compositions, with a satisfactory degree of cross-linking (αc = 0.10, CRI = 4.11 min−1), good mechanical strength (TSb = 5 MPa), satisfactory tear resistance (Ts = 2.9 N/mm), and very high flame resistance (OI = 30%, HRRmax = 283 kW/m2). Filled products could be used as non-combustible materials, confirming the low fire hazard (1/tflashover = 3.5–6.4 kW/m2∙s). The most effective filler of the tested composites was nano-sized silica. [ABSTRACT FROM AUTHOR]

In this investigation, composite poly(lactic acid) (PLA) systems of hollow glass microspheres (MS) and carbonyl iron particles (CIP) were processed and characterized to investigate the effects of using conductive and insulating particles as additives in a polymer system. PLA-MS and PLA-CIP were set at the two levels of 3.94 and 7.77 vol.% for each particle type to study the effects of the particle material type and loading on neat PLA’s thermal properties. It was observed during the twin-screw extrusion that the addition of CIP greatly decreased the viscosity of the PLA melt during processing. Correlations determined using thermogravimetric analysis, differential scanning calorimetry, thermal conductivity, and shear rheology provided insights into how thermal stability was affected. The incorporation of MS and CIP altered thermal properties such as the glass transition temperature (Tg), melting temperature (Tm), and cold crystallization temperature (Tcc). The metal CIP-filled systems had large increases in their thermal conductivity values and viscoelastic transitions compared to those with PLA that were correlated with the observed overheating during extrusion.

In this work, few precursors (MnCl2.4H2O, MnCO3, MnO2, and KMnO4) were simply heated at 650 ​°C for 10 ​h and examined their phase formation and thermal features of Mn-based oxides. Cubic Mn2O3 phase materials with space group, Ia-3 (206) formed for the heat treated products of MnCl2.4H2O and MnO2 precursors. However, the purity is differed for the heat treated product of MnCl2.4H2O, for this three weak impurities are noted along with the major Mn2O3 phase. Mixed phases of Mn2O3 and Mn5O8 were observed for the heating of MnCO3 precursor. The resemblance of δ-MnO2 phase was observed for the heat treated product of KMnO4 precursors. While the heat treated products of MnCl2.4H2O, MnCO3, and MnO2 precursors show the low weight loss of 1.5–3.3 %, the heat treated KMnO4 precursor shows relatively high weight loss of 22.6 % with weak exothermic and endothermic peaks at 100 and 797 ​°C, respectively. The Mn2O3 nanomaterials exhibit a morphology resembling nanorods.

As potential precursors for the synthesis of fluoroperovskites, a family of heavy alkali metal (MI = K, Cs) fluorinated β-diketonates were prepared and characterized by elemental analysis, IR, and powder-XRD. The crystal structures of the new six complexes, MI(β-dikF)(H2O)X, X = 0 or 1, were also determined. The structural diversity of this poorly explored class of complexes was discussed, including the preferred types of cation polyhedra and the ligand coordination modes, and the thermal properties of the metal β-diketonates were studied by TG–DTA in an inert (He) atmosphere. The data obtained allowed us to reveal the effect of the metal cation and the terminal substituent on the structural and thermal features of this family of complexes. [ABSTRACT FROM AUTHOR]

In this investigation, composite poly(lactic acid) (PLA) systems of hollow glass microspheres (MS) and carbonyl iron particles (CIP) were processed and characterized to investigate the effects of using conductive and insulating particles as additives in a polymer system. PLA-MS and PLA-CIP were set at the two levels of 3.94 and 7.77 vol.% for each particle type to study the effects of the particle material type and loading on neat PLA's thermal properties. It was observed during the twin-screw extrusion that the addition of CIP greatly decreased the viscosity of the PLA melt during processing. Correlations determined using thermogravimetric analysis, differential scanning calorimetry, thermal conductivity, and shear rheology provided insights into how thermal stability was affected. The incorporation of MS and CIP altered thermal properties such as the glass transition temperature (Tg), melting temperature (Tm), and cold crystallization temperature (Tcc). The metal CIP-filled systems had large increases in their thermal conductivity values and viscoelastic transitions compared to those with PLA that were correlated with the observed overheating during extrusion. [ABSTRACT FROM AUTHOR]

The manufacturing method influences the properties of the produced components. This work investigates the influence of manufacturing methods, such as fused deposition modeling (3D printing) and injection molding, on the water absorption and mechanical and thermal properties of the specimens produced from neat bio-based poly(lactic acid) (PLA) polymer and poly(lactic acid)/wood composites. Acrylonitrile butadiene styrene (ABS) acts as the reference material due to its low water absorption and good functional properties. The printing layer thickness is one of the factors that affects the properties of a 3D-printed specimen. The investigation includes two different layer thicknesses (0.2 mm and 0.3 mm) while maintaining uniform overall thickness of the specimens across two manufacturing methods. 3D-printed specimens absorb significantly higher amounts of water than the injection-molded specimens, and the increase in the layer thickness of the 3D-printed specimens contributes to further increased water absorption. However, the swelling due to water absorption in 3D-printed specimens decreases upon increased layer thickness. The tensile, flexural, and impact properties of all of the specimens decrease after water absorption, while the properties improve upon decreasing the layer thickness. Higher porosity upon increasing the layer thickness is the predominant factor. The results from dynamic mechanical analysis and microscopy validate the outcomes. The results from this experimental study highlight the limitations of additive manufacturing. [ABSTRACT FROM AUTHOR]

Advanced electronics technology is moving towards smaller footprints and higher computational power. In order to achieve this, advanced packaging techniques are currently being considered, including organic, glass, and semiconductor-based substrates that allow for 2.5D or 3D integration of chips and devices. Metal-core substrates are a new alternative with similar properties to those of semiconductor-based substrates but with the added benefits of higher flexibility and metal ductility. This work comprehensively compares the thermal properties of a novel metal-based substrate, molybdenum, and silicon and fused silica glass substrates in the context of system-on-foil (SoF) integration. A simple electronic technique is used to simulate the heat generated by a typical CPU and to measure the heat dissipation properties of the substrates. The results indicate that molybdenum and silicon are able to effectively dissipate a continuous power density of 2.3 W/mm2 as the surface temperature only increases by ~15 °C. In contrast, the surface temperature of fused silica glass substrates increases by >140 °C for the same applied power. These simple techniques and measurements were validated with infrared camera measurements as well as through finite element analysis via COMSOL simulation. The results validate the use of molybdenum as an advanced packaging substrate and can be used to characterize new substrates and approaches for advanced packaging. [ABSTRACT FROM AUTHOR]

Thermal properties are important factors to determine the proper manufacturing, processing, and storing of biocomposites. Therefore, the thermal properties of the biocomposite made from acetylated betung bamboo pulp and polypropylene (PP) were investigated. The biocomposite was manufactured by hot pressing at 180 oC for 2 minutes and the fiber contents of the acetylated bamboo pulp used were 10 and 20% according to PP weight. The influence of acetylation and fiber content of bamboo pulp on the thermal properties of the biocomposite were investigated by using differential scanning calorimeter (DSC) and thermogravimetric analyzer (TGA). The results showed that acetylated bamboo pulp-PP biocomposite’s were higher than its pure and untreated biocomposites. The rate of crystallization growth of the acetylated bamboo pulp-PP biocomposites was faster up to 4.5 fold than pure PP composite. In addition, its acetylated bamboo pulp-PP had higher onset and maximum decomposition temperature than its untreated fiber-PP biocomposites but lower than PP. According to the results, the best thermal properties of biocomposite were obtained by acetylation of bamboo pulp with 10% fiber content.

Plant-based natural fibres have great potential to replace synthetic materials. They come from renewable resources and are biodegradable. The physical, structural, and thermal properties of lignocellulosic fibres can be slightly modified by adopting various fibre extraction methods and chemical treatments. This research aims to compare the structural and thermal properties of Bauhinia vahlii fibres (BVFs) extracted by the different extraction processes. The Bauhinia vahlii bark was treated with 10% (w/w) and 15% (w/w) NaOH solution at 95oC for two hours, followed by mechanical and manual extraction and comparison of the structural and thermal properties. Bauhinia vahlii fibres extracted with 15% NaOH solution (BVFs15) have higher crystallinity and more surface roughness than fibres extracted with 10% NaOH (BVFs10). Thermal analysis indicates that the maximum thermal degradation temperature and kinetic activation energy are slightly higher for Bauhinia vahlii fibres extracted with a 15% NaOH solution. The BVFs15 has improved structural and thermal properties and can be used for natural yarn manufacture.

A hypersonic electromagnetic railgun projectile undergoes severe aero-heating with an increase in altitude. The purpose of this study was to investigate the characteristics of the shock layer flow field as well as the thermal environment of the blunt body wall of a hypersonic electromagnetic railgun projectile at different launching angles. The two-temperature model considers the thermal nonequilibrium effect and is introduced into the Navier–Stokes (N-S) equation, and it is solved using the finite volume method (FVM). The reliability of the calculation model in terms of thermal properties and composition production was verified against a blunted-cone-cylinder–flare (HB-2) test case. The surface temperature of the hypersonic blunt projectile was simulated using a radiation balance wall boundary. The thermal characteristics at the emission angles α = 60° and α = 45° were checked within an altitude range of 0–70 km, including the nonequilibrium effect, reaction heat release, aerodynamic heat flux, and wall temperature. The results show that the translational rotational temperature is higher than the vibrational electronic temperature, and the thermal nonequilibrium effect increases with an increase in altitude. Comparing the two launching angles, the nonequilibrium degree and reaction heat release at α = 60° were higher than those at α = 45°. The rates of exothermic reaction decreased with an increase in altitude. The heat flux along the wall of the generatrix decreased sharply from the stagnation point. With an increase in altitude, the heat flux dropped sharply from 7 MW/m2 at H = 0 km to approximately 2 MW/m2 at H = 70 km. The wall temperature distribution was similar to the heat flux distribution; however, the surface temperature decreased less rapidly than the heat flux. [ABSTRACT FROM AUTHOR]

This article explores wood-fiber-based fabrics containing Lyocell yarn in the warp and Spinnova–Lyocell (60%/40%) yarn in the weft, which are used to form unidirectional all-cellulose composites (ACC) through partial dilution in a NaOH–urea solution. The aim is to investigate the role of the yarn orientation in composites, which was conducted by measuring the tensile properties in both the 0° and 90° directions. As a reference, thermoplastic biocomposites were prepared from the same fabrics, with biobased polypropylene (PP) as the matrix. We also compared the mechanical and thermal properties of the ACC and PP biocomposites. The following experiments were carried out: tensile test, TGA, DSC, DMA, water absorption test and SEM. The study found no significant difference in tensile strength regarding the Spinnova–Lyocell orientation between ACC and PP biocomposites, while the composite tensile strength was clearly higher in the warp (Lyocell) direction for both composite variants. Elongation at break doubled in ACC in the Lyocell direction compared with the other samples. Thermal analysis showed that mass reduction started at a lower temperature for ACC, but the thermal stability was higher compared with the PP biocomposites. Maximum thermal degradation temperature was measured as being 352 °C for ACC and 466 °C for neat PP, and the PP biocomposites had two peaks in the same temperature range (340–474 °C) as ACC and neat PP combined. ACCs absorbed 93% of their own dry weight in water in just one hour, whereas the PP biocomposites BC2 and BC4 absorbed only 10% and 6%, respectively. The study highlights the different properties of ACC and PP reference biocomposites that could lead to further development and research of commercial applications for ACC. [ABSTRACT FROM AUTHOR]

Six noble two-dimensional lanthanide complexes [Ln(2,4-DFBA)3(terpy)·H2O]·H2O (Ln = Tb(1), Dy(2)), [Pr(2,4,6-TMBA)3(terpy)·H2O] (3) [Nd(2,4,6-TMBA)3(terpy)·H2O]·C2H5OH·H2O(4) and [Ln(2,4,6-TMBA)3(terpy)·H2O]·1.5H2O (Ln = Dy(5), Ho(6) (2,4-DFBA = 2,4-difluorobenzoate, 2,4,6-TMBA = 2,4,6-trimethylbenzoate, terpy = 2,2 ': 6′, 2 ''- terpyridine) were synthesized by conventional solution method with 2,4-difluorobenzoic acid and 2,4,6-trimethylbenzoic acid as main ligands and 2,2 ': 6′, 2 ''- terpyridine as auxiliary ligands. The complexes were characterized by infrared spectroscopy and Raman spectroscopy, and the thermal decomposition mechanism of the complex was studied by TG-DTG-DSC/FTIR coupling technology. The solid fluorescence test was also carried out for complexes 1,2 and 4. It was found that the complexes have good fluorescence properties, and the fluorescence lifetime of complex 1 was 0.541 ms.

Copolymers with two distinguished reactive repeating units are of great interest, as such copolymers might open the possibility of obtaining selective and/or consequent copolymers with different chemical structures and properties. In the present work, copolymers based on two active esters (pentafluorophenyl methacrylate and p-nitrophenyl methacrylate) with varied compositions were synthesized by Cu(0)-mediated reversible deactivation radical polymerization. This polymerization technique allows the preparation of copolymers with high to quantitative conversion of both comonomers, with moderate control over dispersity (Đ = 1.3–1.7). Additionally, by in-depth study on the composition of each copolymer by various techniques including elemental analysis, NMR, FT-IR, and XPS, it was possible to confirm the coherence between expected and obtained composition. Thermal analyses by DSC and TGA were implemented to investigate the relation between copolymers' composition and their thermal properties. Finally, an evaluation of the difference in reactivity of the two monomer moieties was confirmed by post-modification of copolymers with a primary amine and a primary alcohol as the model. [ABSTRACT FROM AUTHOR]

Abstract The aim in this work was to investigate the change in microstructure, phase transformation temperatures, and thermal properties due to the quenching of the investigated Cu-Al-Mn and Cu-Al-Mn-Ti alloys in ribbon form. This paper presents the results of microstructure analysis and thermal properties of Cu-Al-Mn and Cu-Al-Mn-Ti shape memory alloys produced in ribbon form by melt spinning technique. The microstructural analysis was carried out before and after quenching. After casting of the investigated alloys, annealing at 900 °C for 30 min was performed, followed by water quenching. The microstructural analysis was carried out by optical and scanning electron microscopy equipped with an energy dispersive spectrometer and by X-ray diffractometer. Thermodynamic calculation of a ternary Cu-Al-Mn system in equilibrium condition was performed using Thermo-Calc 5 software. Phase transformation temperatures were determined by differential scanning calorimetry and electrical resistance measuring. The results of microstructural analysis show the presence of martensite microstructures before and after quenching in the Cu-Al-Mn alloy, while in the Cu-Al-Mn-Ti alloy martensite microstructure exists only after quenching. Phase transformation temperatures decreased after quenching and titanium addition. [ABSTRACT FROM AUTHOR]

The phenomenon of fire or even explosion caused by thermal runaway of lithium-ion power batteries poses a serious threat to the safety of electric vehicles. An in-depth study of the core-material thermal runaway reaction mechanism and reaction chain is a prerequisite for proposing a mechanism to prevent battery thermal runaway and enhance battery safety. In this study, based on a 24 Ah commercial Li(Ni0 6Co0.2Mn0.2)O2/graphite soft pack battery, the heat production characteristics of different state of charge (SOC) cathode and anode materials, the separator, the electrolyte, and their combinations of the battery were investigated using differential scanning calorimetry. The results show that the reaction between the negative electrode and the electrolyte is the main mode of heat accumulation in the early stage of thermal runaway, and when the heat accumulation causes the temperature to reach a certain critical value, the violent reaction between the positive electrode and the electrolyte is triggered. The extent and timing of the heat production behaviour of the battery host material is closely related to the SOC, and with limited electrolyte content, there is a competitive relationship between the positive and negative electrodes and the electrolyte reaction, leading to different SOC batteries exhibiting different heat production characteristics. In addition, the above findings are correlated with the battery failure mechanisms through heating experiments of the battery monomer. The study of the electro-thermal properties of the main materials in this paper provides a strategy for achieving early warning and suppression of thermal runaway in batteries. [ABSTRACT FROM AUTHOR]

Polymer materials and their composites are one of the most frequently used materials in the packaging and food industries. This applies to both disposable and reusable packaging, layered films with barrier properties, as well as densely overprinted polymer films and metallized food wrap films. According to statistical data from Plastics Europe, approximately 40% of processed thermoplastics are used to produce packaging, including single- and multi-layer film packaging. Growing requirements and new EU directives require the use of recycled materials in new products, which is not easy because the properties of recyclates may differ significantly from those of the primary materials with which the former are mixed. This work attempts to analyze the properties of the primary material used to produce a film using the casting method in comparison with the industrial recyclate obtained by the processing of film made of the primary material and then overprinted and metallized. The process of obtaining re-granulates and preparing test samples was presented, and the mechanical, structural, and thermal properties of the tested materials were compared. The conducted research and the obtained results demonstrated the advisability of conducting advanced mechanical recycling, which leads to obtaining re-granulates with repeatable processing properties and thermal and mechanical properties comparable to the original material despite the impurities they contain. [ABSTRACT FROM AUTHOR]

The aim in this work was to investigate the change in microstructure, phase transformation temperatures, and thermal properties due to the quenching of the investigated Cu-Al-Mn and Cu-Al-Mn-Ti alloys in ribbon form. This paper presents the results of microstructure analysis and thermal properties of Cu-Al-Mn and Cu-Al-Mn-Ti shape memory alloys produced in ribbon form by melt spinning technique. The microstructural analysis was carried out before and after quenching. After casting of the investigated alloys, annealing at 900 °C for 30 min was performed, followed by water quenching. The microstructural analysis was carried out by optical and scanning electron microscopy equipped with an energy dispersive spectrometer and by X-ray diffractometer. Thermodynamic calculation of a ternary Cu-Al-Mn system in equilibrium condition was performed using Thermo-Calc 5 software. Phase transformation temperatures were determined by differential scanning calorimetry and electrical resistance measuring. The results of microstructural analysis show the presence of martensite microstructures before and after quenching in the Cu-Al-Mn alloy, while in the Cu-Al-Mn-Ti alloy martensite microstructure exists only after quenching. Phase transformation temperatures decreased after quenching and titanium addition.

Energy sustainability represents an important research topic for aiding decreasing energy dependence and slowing down climate changes. In this context, solutions using thermal energy storage through rock start to emerge, due to its natural benefits, when compared to more polluting alternatives. To understand whether a rock material can be considered a good thermal energy storage material for such solutions, it is necessary to evaluate the physical, chemical and thermal properties of such materials. Therefore, it becomes essential to understand how heat propagates in the rock and how voids influence the thermal properties. To achieve these goals, hematite ore from Moncorvo, Northeastern Portugal was used, in particular, to study the effect of grain size on thermal properties for three different sized lots. Chemical and physical changes between heated and unheated lots were detected using X-ray diffraction and particle size, as well as X-ray fluorescence analysis. Regarding thermal properties, a hot wire method approach was used with seven thermocouples. Additionally, a thermal inversion model to simulate the heat exchanges was also proposed, allowing changing the properties of the constituents, to fit the theoretical and experimental temperature curve. Furthermore, the model reveals how heat propagates inside the reservoir filled with hematite ore. [ABSTRACT FROM AUTHOR]

The development of polymer materials causes their huge expansion into various areas of everyday life, as well as plant and animal production. Their chemical resistance, good physical properties, and ease of processing result in an increasing use of this group of materials. Outdoor plant production both in open plantations and greenhouses requires various types of materials supporting the vegetation process as well as protecting against pests and weeds. A large group here are various types of materials used for covers of field crops, the main role of which is to prevent uncontrolled and excessive growth of weeds and thus reduce the use of herbicides as plant protection products. Cover films also have other important functions, such as reducing direct water evaporation, better moisture retention around the root system, increasing soil temperature (faster vegetation), etc. However, as always, the problem of introducing new material into agriculture production and the difficulty of its disposal arises. In recent times, farmers' interest in various forms of mulch to protect crops and increase yields has grown significantly. In the publication, the authors attempted to analyze selected commercial properties, but also mulch produced on a laboratory scale, based on biodegradable and petroleum-derived materials. [ABSTRACT FROM AUTHOR]

Between tetrapyrrole macrocycles, porphyrazines show both special physical and chemical properties as metal free and transition metal complexes. Many new studies have demonstrated effective coordination chemistry, great chemical, thermal, and photochemical stability, as well as technological applications to this macrocycle. In the work, it has been planned to synthesize asymmetric porphyrazine having seven ethylsulfanyl groups and one bromine by using a different method. In this way, asymmetric(ethylsulfanyl) porphyrazines were synthesized by replacing one ethylsulfanyl-alkyl chain on macrocycle with a hydrojen atom. The bromination of this product has resulted monobromoporphyrazine derivative. Thermal analysis of the compounds were done by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) (between 50-1200°C). The structures of these compounds were characterized by using UV, FT-IR, MS, 1H NMR, elementel analysis. [ABSTRACT FROM AUTHOR]

This study explores the effect of alkali treatment at ambient (25 °C) and elevated temperatures (100 °C) on the physicochemical, structural, morphological, and thermal properties of Calamus tenuis cane fibers (CTCFs) for the first time. Our purpose is to investigate their potential use as reinforcement in polymer composites, since cane fibers are generally known for their accurate and consistent geometrical orientation. Treatment with 8% (w/v) sodium hydroxide (NaOH) is carried out at ambient temperature and at 100 °C for 4 h. Chemical analysis and Fourier transform IR spectroscopy (FTIR) indicate some removal of non-cellulosic elements from CTCFs during alkali treatment, resulting in increased surface roughness, as confirmed by using SEM micrographs. This removal of non-cellulosic elements leads to an enhancement in the density of the treated CTCFs. Untreated and treated fibers are analyzed for maximum degradation temperature, thermal stability, and kinetic activation energy (Ea) using thermogravimetric analysis (TGA). In particular, Ea was considerably diminished with treatment and temperature. X-ray diffraction (XRD) results show an improved crystallinity index (37.38% to 44.02%) and crystallite size (2.73 nm to 2.98 nm) for fibers treated with 8% NaOH at ambient temperature. In conclusion, a general benefit was achieved by treating CTCFs, though the influence of increasing temperature treatment appears controversial.

This article describes the use of microwave irradiation in the synthesis of bis(cyclo carbonate) compounds (BCCs) in bulk (without solvent) from carbon dioxide capture using an epoxidized compound—a commercial epoxy resin—and compares this process to the conventional method. CO2 cycloaddition to epoxides is an ecological and efficient method for the formation of bis(cyclic carbonates). Moreover, the introduction of gas into the reaction mixture was carried out at atmospheric pressure with a controlled flow rate, which is advantageous from an economic point of view. Progressive structural changes and the presence of characteristic chemical groups were monitored using attenuated total reflectance infrared spectroscopy with Fourier transform. The obtained crude products were purified to obtain three fractions, which were subjected to detailed structural analysis using FT-IR and 13CNMR. The formation of the main product with two cyclic carbonates was confirmed. The presence of monomers, dimers and trimers in individual fractions as well as their thermal stability were determined, and the molecular masses in individual fractions were determined using gel permeation chromatography (GPC). [ABSTRACT FROM AUTHOR]

The radical statistical copolymerization of N–vinyl pyrrolidone (NVP) and 2–chloroethyl vinyl ether (CEVE) was conducted using the Reversible Addition–Fragmentation chain Transfer (RAFT) polymerization technique, employing [(O–ethylxanthyl)methyl]benzene (CTA-1) and O–ethyl S–(phthalimidylmethyl) xanthate (CTA-2) as the Chain Transfer Agents (CTAs), leading to P(NVP–stat–CEVE) products. After optimizing copolymerization conditions, monomer reactivity ratios were estimated using various linear graphical methods, as well as the COPOINT program, which was applied in the framework of the terminal model. Structural parameters of the copolymers were obtained by calculating the dyad sequence fractions and the monomers' mean sequence lengths. Thermal properties of the copolymers were studied by Differential Scanning Calorimetry (DSC) and kinetics of their thermal degradation by Thermogravimetric Analysis (TGA) and Differential Thermogravimetry (DTG), applying the isoconversional methodologies of Ozawa–Flynn–Wall (OFW) and Kissinger–Akahira–Sunose (KAS). [ABSTRACT FROM AUTHOR]

This study explores the effect of alkali treatment at ambient (25 °C) and elevated temperatures (100 °C) on the physicochemical, structural, morphological, and thermal properties of Calamus tenuis cane fibers (CTCFs) for the first time. Our purpose is to investigate their potential use as reinforcement in polymer composites, since cane fibers are generally known for their accurate and consistent geometrical orientation. Treatment with 8% (w/v) sodium hydroxide (NaOH) is carried out at ambient temperature and at 100 °C for 4 h. Chemical analysis and Fourier transform IR spectroscopy (FTIR) indicate some removal of non-cellulosic elements from CTCFs during alkali treatment, resulting in increased surface roughness, as confirmed by using SEM micrographs. This removal of non-cellulosic elements leads to an enhancement in the density of the treated CTCFs. Untreated and treated fibers are analyzed for maximum degradation temperature, thermal stability, and kinetic activation energy (Ea) using thermogravimetric analysis (TGA). In particular, Ea was considerably diminished with treatment and temperature. X-ray diffraction (XRD) results show an improved crystallinity index (37.38% to 44.02%) and crystallite size (2.73 nm to 2.98 nm) for fibers treated with 8% NaOH at ambient temperature. In conclusion, a general benefit was achieved by treating CTCFs, though the influence of increasing temperature treatment appears controversial. [ABSTRACT FROM AUTHOR]

As potential precursors for the synthesis of fluoroperovskites, a family of heavy alkali metal (MI = K, Cs) fluorinated β-diketonates were prepared and characterized by elemental analysis, IR, and powder-XRD. The crystal structures of the new six complexes, MI(β-dikF)(H2O)X, X = 0 or 1, were also determined. The structural diversity of this poorly explored class of complexes was discussed, including the preferred types of cation polyhedra and the ligand coordination modes, and the thermal properties of the metal β-diketonates were studied by TG–DTA in an inert (He) atmosphere. The data obtained allowed us to reveal the effect of the metal cation and the terminal substituent on the structural and thermal features of this family of complexes.

Flexible electronic technology is now widely developed in wearable products for humans and the detection of physiological characteristics, track tracking, and analysis of the living environment for animals and plants. In these application scenarios, flexible electronic devices (FEDs) may work outdoors for a long time and may be exposed to strong solar radiation, which may cause the temperature of FEDs to be too high and affect their stability. Hence, a quantitative description of the thermal properties of FEDs is helpful to provide a reference for the design of related FEDs. This paper establishes a three-dimensional thermal analysis model, verified by the finite element method and experiments, to analyze the temperature increase in the interface of the device under solar radiation and generated by the device itself, and analyzes the parameters that have an influence on the temperature increase in the interface, including the thickness of the substrate and the encapsulated layer and the power of the device. On this basis, the contributions for these parameters to the temperature increase in the interface are further compared. [ABSTRACT FROM AUTHOR]

In the fields of military research, aerospace, and vehicle technology, the thermal stability of Kevlar fiber is critical for improving its flame resistance. In this work, the pad mangle machine was used to improve the thermal properties of Kevlar 29 in order to expand the range of applications for thermal aspects. Silicon carbide and titanium oxide nanoparticles provide thermal stability on the fiber surface through intermolecular adhesion. Here, 5 wt% and 10 wt% of nanoparticles with various mass ratios (1:1) have been chosen. Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) analysis, and X-ray Photoelectron Spectroscopy (XPS) analysis have all been used to measure different thermal properties. The surface morphology of samples is represented by FESEM analysis, while the active organic groups are represented by FTIR analysis. The greater crystallization of epoxy and nanoparticles is linked to post-heat treatment of the material. The glass transition temperature of the coated samples shifted maximum from 559.13 °C to 580.51 °C, the end set temperature increased by 30.67 °C compared to the uncoated sample, and the residual weight changed from 29.77 percent to 4.06 percent, according to the findings (i.e., lightweight). When compared to the uncoated sample, the coated sample's enthalpy increased significantly (i.e., the samples can absorb more heat). The smaller the positive binding energy, the higher the activation energy, and hence the slower the chemical reaction, which is especially important in high-temperature applications. Finally, this research reveals a 4.5–5.2 percent increase in thermal characteristics.

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]

The devitrification, "cold" crystallization, and glass transition temperatures and melting point of samples in the B2O3–CaO–Al2O3–PbO system have been determined by differential thermal analysis. The viscosity of aluminum calcium borate melts containing up to 6.9% PbO has been measured in the temperature range 1153–1573 K. The results demonstrate that lead oxide additions reduce melt viscosity and that the density and surface tension of the melts increase with increasing lead oxide content and decrease with increasing temperature. High- and low-temperature regions have been identified where the melts have properties of Newtonian fluids. Cooling leads to polymerization and vitrification of the melts. [ABSTRACT FROM AUTHOR]

The use of phase change materials (PCMs) in concrete is a double-edged sword that improves the thermal inertia but degrades the mechanical properties of concrete. It has been an essential but unsolved issue to enhance the thermal capacity of PCMs while non-decreasing their mechanical strength. To this end, this work designs a novel 3D printing phase change aggregate to prepare concrete with prominent thermal capacity and ductility. The work investigated the effects of 3D printing phase change aggregate on the compressive strength and splitting tensile strength of concrete. The compressive strength of phase change aggregate concrete is 21.18 MPa, but the ductility of concrete improves. The splitting tensile strength was 1.45 MPa. The peak strain is 11.69 × 10−3, nearly 13 times that of basalt aggregate concrete. Moreover, using 3D printing phase change aggregate reduced concrete's early peak hydration temperature by 7.1%. The thermal insulation capacity of the experiment cube model with phase change concrete has been improved. The results show that the novel 3D printing change aggregate concrete has good mechanical properties and latent heat storage, providing a guideline for applying PCMs in building materials. [ABSTRACT FROM AUTHOR]

The physical, chemical, structural, crystallographic, thermal and surface topographical properties of fiber extracted from the steam of Eichhornia crassipes (EC) plant was characterized for the first time in this study. Physical and chemical analysis results revealed that Eichhornia crassipes fiber (ECF) has comparatively lower density (1350 kg/m3) and higher cellulose content (59.86 wt.%). The chemical functional groups and relevant chemical composition of the ECF were documented by the FTIR. The XRD results acknowledged that ECF has the crystallinity index (44.32%) and crystalline size of 5.09 nm, respectively. Thermogravimetric analysis (TGA) and differential scanning calorimeter analysis (DSC) results of ECF exhibited that it can be thermally stable up to 200° C. All the results of ECF establish that it is a suitable substitute for the artificial fibers used as reinforcement in fiber-reinforced plastics.

The radical statistical copolymerization of N–vinyl pyrrolidone (NVP) and 2–chloroethyl vinyl ether (CEVE) was conducted using the Reversible Addition–Fragmentation chain Transfer (RAFT) polymerization technique, employing [(O–ethylxanthyl)methyl]benzene (CTA-1) and O–ethyl S–(phthalimidylmethyl) xanthate (CTA-2) as the Chain Transfer Agents (CTAs), leading to P(NVP–stat–CEVE) products. After optimizing copolymerization conditions, monomer reactivity ratios were estimated using various linear graphical methods, as well as the COPOINT program, which was applied in the framework of the terminal model. Structural parameters of the copolymers were obtained by calculating the dyad sequence fractions and the monomers’ mean sequence lengths. Thermal properties of the copolymers were studied by Differential Scanning Calorimetry (DSC) and kinetics of their thermal degradation by Thermogravimetric Analysis (TGA) and Differential Thermogravimetry (DTG), applying the isoconversional methodologies of Ozawa–Flynn–Wall (OFW) and Kissinger–Akahira–Sunose (KAS).

In this article, silicone rubber (SiR) is filled with industry preferred micro-silica and specialty hexagonal boron nitride (h-BN) nanosheets, by varying the ratio between the two fillers, while keeping the filler to matrix ratio the same in all three composites. The fillers are added to SiR using an electrostatic disperser which aids in homogenizing the filler-polymer mixture by means of shearing force along with elongation. The performance of synthesized silicone composites are evaluated using thermal, erosion resistance, morphological, mechanical, and high-temperature dielectric properties. Addition of as low as 5 wt% h-BN fillers significantly improved the thermal properties; 6%–20% improvement in thermal conductivity and in less than half the weight loss compared to only silica filled composites with laser erosion. The morphological and mechanical analyses showed improved filler dispersion and filler to silicone matrix interaction owing to good filler dispersion achieved through the electrostatic dispersing method. The dielectric properties measured in wide frequency range, between 10−4 and 103 Hz and at elevated temperatures (up to 175 °C) showed a negligible effect of increase in h-BN content. Thus, this article implies that low amounts of h-BN in silica-silicone composites improve thermal conductivity and erosion resistance significantly and not altering the dielectric responses of these hybrid composites even at elevated temperatures. Hence these composites can find applications both in the high voltage industry and as electronic packaging materials. [ABSTRACT FROM AUTHOR]

Thermal analysis is widely used to investigate the properties of a variety of energetic materials, including the mutual compatibility of components of energetic material mixtures. Although thermal analysis methods are a valuable source of information about energetic materials, their use requires careful consideration of the employed methodology, as well as an understanding of the thermally induced processes taking place within energetic materials. Several case studies involving the study of energetic materials are presented, in order to highlight some of the most relevant issues in the application of thermal analysis methods. Some recommendations about the application of thermal analysis methods and accompanying methodologies for estimating other properties of energetic materials are also included.

Monocrystalline chalcogenide spinels ZnCr2Se4 are antiferromagnetic and semiconductor materials. They can be used to dope or alloy with related semiconducting spinels. Therefore, their Pb-doped display is expected to have unique properties and new potential applications. This paper presents the results of dc and ac magnetic measurements, including the critical fields visible on the magnetisation isotherms, electrical conductivity, and specific heat of the ZnCr2S4:Pb single crystals. These studies showed that substituting the diamagnetic Pb ion with a large ion radius for the Zn one leads to strong short-range ferromagnetic interactions in the entire temperature range and spin fluctuations in the paramagnetic region at Hdc = 50 kOe. [ABSTRACT FROM AUTHOR]

The development of polymer materials causes their huge expansion into various areas of everyday life, as well as plant and animal production. Their chemical resistance, good physical properties, and ease of processing result in an increasing use of this group of materials. Outdoor plant production both in open plantations and greenhouses requires various types of materials supporting the vegetation process as well as protecting against pests and weeds. A large group here are various types of materials used for covers of field crops, the main role of which is to prevent uncontrolled and excessive growth of weeds and thus reduce the use of herbicides as plant protection products. Cover films also have other important functions, such as reducing direct water evaporation, better moisture retention around the root system, increasing soil temperature (faster vegetation), etc. However, as always, the problem of introducing new material into agriculture production and the difficulty of its disposal arises. In recent times, farmers’ interest in various forms of mulch to protect crops and increase yields has grown significantly. In the publication, the authors attempted to analyze selected commercial properties, but also mulch produced on a laboratory scale, based on biodegradable and petroleum-derived materials.

[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]

Monocrystalline chalcogenide spinels ZnCr2Se4 are antiferromagnetic and semiconductor materials. They can be used to dope or alloy with related semiconducting spinels. Therefore, their Pb-doped display is expected to have unique properties and new potential applications. This paper presents the results of dc and ac magnetic measurements, including the critical fields visible on the magnetisation isotherms, electrical conductivity, and specific heat of the ZnCr2S4:Pb single crystals. These studies showed that substituting the diamagnetic Pb ion with a large ion radius for the Zn one leads to strong short-range ferromagnetic interactions in the entire temperature range and spin fluctuations in the paramagnetic region at Hdc = 50 kOe.

The main purpose of the research was to obtain and study hybrid materials based on three different nano-oxides commonly used in the cosmetic and pharmaceutical industries: Al2O3, TiO2, and ZnO, with the natural bioactive polysaccharide fucoidan. Since the mentioned oxides are largely utilized by industry, there is no doubt that the presented studies are important from an environmental point of view. On the basis of the textural studies (dynamic light scattering DLS, low temperature nitrogen adsorption, X-ray diffraction analysis XRD, scanning electron microscopy SEM) it was proved that the properties of the hybrid materials differ from the pure components of the system. Moreover, the advanced thermal analysis (TG-DTG-DSC) combined with the evolved gas analysis using Fourier transformed infrared spectroscopy (FTIR) and mass spectrometry were applied to describe the thermal decomposition of fucoidan, oxides and hybrid materials. It was found that the interactions between the polymer and the oxides results in the formation of the hybrid materials due to the functionalization of the nanoparticles surface, and that their thermal stability increased when compared to the pure substrates. Such findings definitely fill the literature void regarding the fucoidan based hybrid materials and help the industrial formulators in the preparation of new products.

The seeds of berry fruits are a component of fruit waste occurring in the production process. Circular economy rules focus on decreasing the amount of waste produced and reusing by-products when it is possible. To determine the possible applications of the studied fruit industry wastes, the thermal properties of berry seeds and of oil extracted from the tested material were examined. Differential scanning calorimetry (DSC), modulated differential scanning calorimetry (MDSC), and thermogravimetry (TG) of blackberry, chokeberry, and raspberry seeds were carried out. The properties of oil extracted in the Soxhlet apparatus were studied by pressure differential scanning calorimetry (PDSC), TG, and gas chromatography (GC) measurements. The results show that berry seeds lipids are from different melting fraction groups with a dominance of low-melting fraction, which consists of mono- and polyunsaturated fatty acids. There are also occurring residues of carbohydrates and inorganic, thermostable substances in the studied seeds. A GC analysis of oil confirms that the polyunsaturated fatty acids (PUFA) are most abundant and amount to 78.72 ± 0.06% in blackberry seed oil, 73.79 ± 0.14% in chokeberry seed oil, and 82.74 ± 0.03% in raspberry seed oil. The PDSC study showed that the most oxidative stable oil is blackberry seed oil, followed by raspberry and chokeberry seed oils. According to the obtained results, berry seeds can be used as a source of oil in food or other production chains. However, more detailed characteristics of berry seed oils are needed to determine their applicability.

With respect to the fossil resources shortage, the development of bio-based wood adhesives is an important research topic in wood science. There has been research on using sucrose for bio-based adhesives. However, a high acid catalyst content and a high hot-pressing temperature are required when manufacturing particleboards. In this study, to explore the possibility of p-toluenesulfonic acid (PTSA) as a promising acid catalyst for sucrose-based adhesives, the curing behavior of sucrose with PTSA (Suc-PTSA) was clarified. The thermal analysis results showed that the thermal properties of sucrose decreased significantly with the addition of PTSA. Based on the results of the insoluble matter rate, the optimal mixture ratio and heating conditions were determined to be 95:5 and 180 °C for 10 min, respectively. According to the results of FT−IR, the heat-treated Suc-PTSA contained furan compounds. In the context of the dynamic viscoelasticity, the onset temperature at which the storage modulus (E′) begins to rise was significantly lower than those of the other sucrose-based adhesives. PTSA has the potential to cure sucrose more efficiently and at lower temperatures than previous sucrose-based adhesives, making it a promising acid catalyst for sucrose. [ABSTRACT FROM AUTHOR]

The synthesis of glycopolymers by copolymerising an allyl glucosamine (AG) monomer with co-monomers methyl methacrylate (MMA), acrylonitrile (AN) and 2-hydroxyethyl methacrylate (HEMA) was investigated via free-radical polymerisation of 2,2-azobisisobutyronitrile (AIBN) in dimethylformamide (DMF). Three new copolymers, poly(AG-co-MMA), poly(AG-co-AN) and poly(AG-co-HEMA), were obtained. The chemical structures of the glycopolymers were analysed using 1H-NMR, 13C-NMR and FTIR. The thermal properties and degradation kinetics of the three glycopolymers were examined by thermogravimetric (TG) analysis at different heating rates. The effects of different co-monomers on the copolymerisation yield, thermal properties and biological activities of the resulting glycopolymers were investigated. The activation energies of the decomposition stages were calculated using the Flynn–Wall–Ozawa (FWO) and Kissinger methods. Furthermore, the biological activity of AG monomers and glycopolymers was studied and compared to chitosan. Poly(AG-co-HEMA) had the most significant effect on MCF-7 cell viability, and all glycopolymers have a low toxic effect profile on MCF-7 cell lines. [ABSTRACT FROM AUTHOR]

Thermal analysis is widely used to investigate the properties of a variety of energetic materials, including the mutual compatibility of components of energetic material mixtures. Although thermal analysis methods are a valuable source of information about energetic materials, their use requires careful consideration of the employed methodology, as well as an understanding of the thermally induced processes taking place within energetic materials. Several case studies involving the study of energetic materials are presented, in order to highlight some of the most relevant issues in the application of thermal analysis methods. Some recommendations about the application of thermal analysis methods and accompanying methodologies for estimating other properties of energetic materials are also included. [ABSTRACT FROM AUTHOR]