Thermogravimetric Differential Scanning Calorimetry Research Articles

Crosslinking and Swelling Properties of pH-Responsive Poly(Ethylene Glycol)/Poly(Acrylic Acid) Interpenetrating Polymer Network Hydrogels.

This study investigates the crosslinking dynamics and swelling properties of pH-responsive poly(ethylene glycol) (PEG)/poly(acrylic acid) (PAA) interpenetrating polymer network (IPN) hydrogels. These hydrogels feature denser crosslinked networks compared to PEG single network (SN) hydrogels. Fabrication involved a two-step UV curing process: First, forming PEG-SN hydrogels using poly(ethylene glycol) diacrylate (PEGDA) through UV-induced free radical polymerization and crosslinking reactions, then immersing them in PAA solutions with two different molar ratios of acrylic acid (AA) monomer and poly(ethylene glycol) dimethacrylate (PEGDMA) crosslinker. A subsequent UV curing step created PAA networks within the pre-fabricated PEG hydrogels. The incorporation of AA with ionizable functional groups imparted pH sensitivity to the hydrogels, allowing the swelling ratio to respond to environmental pH changes. Rheological analysis showed that PEG/PAA IPN hydrogels had a higher storage modulus (G') than PEG-SN hydrogels, with PEG/PAA-IPN5 exhibiting the highest modulus. Thermal analysis via thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) indicated increased thermal stability for PEG/PAA-IPN5 compared to PEG/PAA-IPN1, due to higher crosslinking density from increased PEGDMA content. Consistent with the storage modulus trend, PEG/PAA-IPN hydrogels demonstrated superior mechanical properties compared to PEG-SN hydrogels. The tighter network structure led to reduced water uptake and a higher gel modulus in swollen IPN hydrogels, attributed to the increased density of active network strands. Below the pKa (4.3) of acrylic acid, hydrogen bonds between PEG and PAA chains caused the IPN hydrogels to contract. Above the pKa, ionization of PAA chains induced electrostatic repulsion and osmotic forces, increasing water absorption. Adjusting the crosslinking density of the PAA network enabled fine-tuning of the IPN hydrogels' properties, allowing comprehensive comparison of single network and IPN characteristics.

The Impact of Boron Nitride Additive on Thermal and Thermochromic Properties of Organic Thermochromic Phase Change Materials.

Thermochromic phase change materials (TPCMs) are gaining increasing interest among scientists. These multifunctional materials can store thermal energy but also, at the same time, during the phase transition, they can change colour. Thermal conductivity is also extremely important for this type of material, which is why various additives are used for this purpose. This work aimed to study the properties of thermochromic phase change materials with an inorganic modifier. Stearic acid, behenyl alcohol, and bromocresol purple were used as thermochromic system components, while boron nitride particles were used as an additive. The key tests for such systems are thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), which allow determining the thermal stability of the materials (at around 170 °C) and phase transition parameters (thermal energy storage of 300 J/g in the range of 40-75 °C). The thermochromic properties were tested, and satisfactory results were obtained. In the end, laser flash analysis (LFA) tests indicated that boron nitride improves the thermal conductivity of the organic thermochromic phase change material by almost 30%. The results showed that the tested materials have great potential as thermochromic phase change materials for thermal energy storage.

Experimental study on the heat treatment reaction process of bentonite

This study focuses on enhancing the pozzolanic activity of bentonite through heat treatment to improve its compressive strength, while also considering its expansion properties for applications. Sodium bentonite was subjected to various temperatures and analyzed using thermogravimetric-differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), and scanning electron microscopy-energy dispersive spectroscopy (SEM–EDS). The results indicated that at 100 °C, adsorbed and interlayer water in montmorillonite was lost, and constitution water was eliminated at 700 °C. With further temperature increases, montmorillonite decomposes into an amorphous phase at 900 °C. At 1100 °C, the amorphous phase recrystallized into magnesium–aluminum silicate, which further decomposed into cristobalite. The study concludes that bentonite heat-treated at 800–900 °C can be effectively used as an additive in mining backfill materials to enhance compressive strength while maintaining its expansion properties.

Pyrolysis of folic acid: Identification of gaseous/volatile products and structural evolution of N-doped graphitic carbon

Folic acid (FA) is a low-cost and suitable source for producing different N-doped carbon materials by pyrolysis. However, the pyrolytic steps of FA are not entirely understood, particularly above 350 °C, which hampers the intelligent design of tailor-made carbon materials by a one-pot route. In this work, the pyrolytic decomposition steps of FA were investigated by simultaneous thermogravimetric analysis (TGA) and differential scanning calorimetry (TGA-DSC). The released gaseous/volatile products were probed by coupling TGA to infrared spectroscopy and mass spectrometry (TGA-FTIR-MS). Considering the thermal analysis data, FA was pyrolysed in a furnace at 350, 430, 570, 800, and 1000 °C, and the products were analysed by X-ray diffractometry (XRD), vibrational spectroscopy, and X-ray photoelectron spectroscopy. In situ high-temperature X-ray diffractometry (HT-XRD) experiments were also conducted under the nitrogen atmosphere. According to the data set, insights about FA decomposition steps could be proposed, including gaseous/volatile products released during the process and the structural evolution of N-doped graphitic carbon. The formation of carbonaceous material initiated between 200 and 350 °C through polymerisation/condensation reactions, and this step was marked by the release of 2-pyrrolidone and aniline. The graphitisation was enhanced above 350 °C, increasing graphitic nitrogen while the amide groups vanished. The process was accompanied by deoxygenation (i.e., CO and CO2 release) and denitrogenation (e.g., NH3, HNCO, and HCN) reactions. In the 570–800 °C range, the N-enrichment of carbon material (N-pyridine, N-pyrrole/Csp2-N in 5,7-membered rings, and nitrile) could occur by the reaction of released NH3 over the char surface. Graphitic-like structures containing mainly N-graphite and N-pyridine were obtained above 800 °C. The original data about the thermal decomposition steps of FA allow for optimising the synthesis of N-doped carbon materials suitable for applications in adsorption, sensing, catalysis, and energy storage.

Determination of optimum production and 3D printer application temperatures for hemp fiber reinforced polycarbonate composites

AbstractThis study delves into optimizing production parameters and 3D printing (3Dp) conditions for alkaline‐treated 10% hemp fiber‐reinforced polycarbonate (PC) composites. Initially, composite filaments were extruded at 250°C (PCH250) and 230°C (PCH230) to assess the impact of varying melt mixing temperatures on thermal behavior. Thermal characterization was conducted using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). DSC analysis indicated consistent glass transition temperatures (Tg) across pure PC and the composites, while TGA revealed minimal thermal degradation in PCH230 compared to pure PC. Subsequently, to ascertain the optimal 3D printing temperature, specimens were printed at temperatures elevated by 10°C relative to their melt mixing temperatures (PCH250/260 and PCH230/240), followed by mechanical evaluation via tensile testing. PCH230/240 exhibited superior mechanical properties, demonstrating a 12% increase in tensile strength and a 29% increase in Young's modulus compared to pure PC. Additional testing at 230°C printing temperature (PCH230/230) demonstrated enhanced mechanical strength over PCH250/260 but inferior performance relative to PCH230/240, attributed to incomplete interlayer adhesion observed through SEM analysis. Consequently, the optimal composite melt mixing temperature was determined to be 230°C, with an accompanying 3D printing temperature of 240°C for optimal mechanical performance.Highlights 3D printable, 5% NaOH treated hemp fiber reinforced polycarbonate composite. Printing composite with 3D printing device at different temperatures 230°C process temperature gives the best thermal properties. 240°C 3Dp temperature provides the best mechanical and morphological properties.

Mechanical and Thermal Properties of 3D-Printed Acrylonitrile Butadiene Styrene Reinforced with Rubberwood Fiber

An additive manufacturing (AM) has become very popular due to its simplicity in producing complicated products using just one process due to the layer-by-layer addition of material, which makes it possible for more complicated products to be created. The constraint of Fused Filament Fabrication (FFF) printed components with inadequate mechanical qualities has prevented AM from being widely adopted by numerous industries. The mechanical and thermal qualities of FFF printed components which is a pure polymer could be enhanced by reinforcing the wood fiber into the polymer. In this study, the twin-screw extruder was used to produce the wood plastic composites (WPCs) filaments, which were made with ABS (Acrylonitrile Butadiene Styrene) as the matrix material and 1-3wt% rubberwood fiber (RWF) for reinforcement. The effects of the extrusion parameter, such as the volume fraction of RWF and the temperature of the extrusion process, on the 3D-printed WPCs samples were investigated. The experimental results of 3D-printed WPC sample were found that the highest compressive strength value is 24.3 MPa, obtained from the rubberwood 1wt% at the extrusion temperature 218 °C whereas the pure ABS filaments obtaining from the commercial and extrusion process gave the values of 28.9 and 14.5 MPa, respectively. The highest value of tensile strength is 8.4 MPa with the rubberwood 2wt% and temperature 198 °C whereas the pure ABS filaments obtaining from the commercial and extrusion process gave the values of 10.9 and 7.4 MPa, respectively. The morphological analysis of the 3D-printed WPC sample was observed to exhibit an effect of printing process. The result showed that an increasing temperature of extrusion process increases both tensile and compressive strengths of the samples whereas an increasing amount of fiber increases the tensile strength but decreased the compressive strength. Analysis of variance demonstrated linear factor and 2-way interaction factor of the extrusion parameter influence on compression and tensile strength significantly. The rubberwood 2wt% and the temperature 218 °C was suggested to achieve the suitable condition for extrusion process for the 3D-printed WPC sample. In addition, the discussions were supported with the thermal properties achieved from Thermogravimetric analysis and Differential Scanning Calorimetry.

Pyrolysis of high-density polyethylene: Degradation behaviors, kinetics, and product characteristics

Pyrolysis is a promising technology for converting plastic waste into valuable raw materials while offering a potential solution to the global plastic pollution crisis. In this study, the thermal pyrolysis of high-density polyethylene (HDPE) is investigated in a drop tube reactor under nearly isothermal conditions. The impact of reaction temperature and gas/volatile residence time on carbon conversion and product distribution is examined across a range of 500–900 °C and 3.6–32.2 s, respectively. Non-condensable gas products detected by online mass spectrometry are H2, CH4, C2H4, C2H6, C3H6, and C3H8. At elevated temperatures and prolonged residence time, H2 yield reaches as high as 8.6 wt% of the initial HDPE mass due to intensified cracking reactions of C2–C3 hydrocarbons and long-chain aliphatic compounds. Consequently, pyrolysis tars consist mainly of polycyclic aromatic hydrocarbons (PAHs) with 5–7 rings, accompanied by visible coke deposition within the reactor. HDPE decomposition to volatiles is an endothermic process and it is complete at a temperature between 492 °C and 525 °C, depending on the heating rate employed, from non-isothermal thermogravimetric analysis and differential scanning calorimetry (TGA-DSC) measurements. The thermal degradation of HDPE pellets follows the two-dimensional nucleation growth model for conversion levels up to 0.8 with an apparent activation energy of 259–270 kJ/mol and a pre-exponential factor of 4.83 × 1017–1.37 × 1019 min−1, determined from various isoconversional methods such as Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), and Starink, along with Criado's master plots. These findings provide valuable insights into optimizing process parameters and refining reactor design for pyrolysis, which can be integrated with gasification and reforming processes to enhance hydrogen production on a larger scale.

Improving the interfacial properties of carbon fiber/low melting point PAEK composites by embellishing of bio-based PAEK sizing agent

In this study, a bio-based polyarylene ether ketone (bio-PAEK) was synthesized to prepare water-based sizing agents for enhancing the interfacial adhesion between carbon fiber (CF) and matrix. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) results indicated that the bio-PAEK exhibited good thermal properties. To improve the processability and reduce the processing temperature, PAEK with a low melting point (LMPAEK) was also used as the matrix resin. The glass-transition temperature (Tg) of LMPAEK was slightly higher than that of polyether ether ketone (PEEK), but its melting temperature (Tm) was lower 48.5 °C. A strong interface was created after introducing sizing agents onto the CF surface due to good compatibility between fibers and matrix. The interlaminar shear strength (ILSS), interfacial shear strength (IFSS) and flexural strength of CF2/LMPAEK composites increased by 54.7 %, 56.0 % and 46.6 %, respectively, compared with the untreated composites. This study provided a novel approach to prepare water-based bio-PAEK sizing agents for CF composites with a low melting point matrix to be applied in additive manufacturing.

Well-defined triphenylamine-containing polymers as hole-transporting layers in solution-processable organic light-emitting diodes via living anionic polymerization

In this study, we conducted anionic polymerization of N-[1,1′-biphenyl]-4-yl-N-(4′-ethenyl[1,1′-biphenyl]-4-yl)-9,9-dimethyl-9H-fluoren-2-amine (A) incorporating a triphenylamine group as a hole-transporting unit using sec-butyllithium and potassium naphthalenide as initiators in tetrahydrofuran at −30 ℃ for 10 min. The resultant poly(A)s exhibited controlled molecular weights (Mn = 20.9−126.3 kg/mol) and narrow molecular weight distributions (Mw/Mn ≤ 1.12). The living nature of the propagating chain end of poly(A) was confirmed by postpolymerization. Additionally, block copolymerization of A with styrene (St) and 2-vinylpyridine (2VP) was performed to assess its relative reactivity. Copolymerization resulted in the precise synthesis of well-defined block copolymers with poly(A) segments. Thermal properties of poly(A) were investigated using thermogravimetric analysis and differential scanning calorimetry. Notably, the thermal annealing of poly(A) film at 230 ℃ for 10 min made it insoluble in toluene, indicating its solvent resistance. Thus, poly(A) was used as the hole-transporting layer (HTL) in solution-processable organic light-emitting diodes (OLEDs). A comparative analysis against a reference device containing poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) revealed an enhancement in the performance of the OLED comprising thermally annealed poly(A) as the HTL. These results strongly suggest that poly(A) is a promising HTL material for solution-processable OLEDs.

Effect of magnetite and graphene nanoplatelets on mechanical properties and thermal stability of thermoplastic elastomer

ABSTRACT Functional nanocomposites have garnered considerable attention due to their ability to exhibit multifunctional properties and achieve exceptional performance. This current paper aims to analyze the individual and combined effects of magnetite (Fe3O4) and Graphene nanoplatelets (GNPs) on the mechanical, thermal, and morphological properties of a blend consisting Thermoplastic elastomer (TPE) which is made up of Natural rubber (NR) and Polyaniline (PANi). Both nanocomposites were fabricated via melt blending method using an internal mixer, followed by compression via hot/cold pressing. The incorporation of Fe3O4 was observed to consistently enhance the flexural and impact properties compared to GNP-based nanocomposites. Notably, the nanocomposites filled with 6 wt% Fe3O4 displayed the highest flexural strength (2.1 MPa), flexural modulus (31.1 MPa), and impact strength (4.4 kJ/m2). Results from thermogravimetric analysis and differential scanning calorimetry demonstrated a significant improvement in thermal stability within the nanocomposites. The introduction of nanoparticles led to a delay in decomposition and melting processes. The hybridization of Fe3O4 and GNP proved effective in synergistically enhancing both mechanical performance and thermal stability. At optimum content, scanning electron microscopy micrographs revealed a uniform dispersion of Fe3O4/GNPs within the TPE-PANi blend, accompanied by strong interactions between the components.

Prospects of mono cellulosic and cellulosic-glass hybrid fillers reinforced polypropylene composites

The objective of the study was to investigate the flexural mechanical, thermal and morphological properties of polypropylene composites reinforced with cellulose and glass particles. Polypropylene lacks sufficient strength and stiffness for many applications. By reinforcing it with cellulose and glass particles, the study was aimed at enhancing these mechanical properties, addressing the need for stronger and more durable materials. These composites are likely to find applications in the automotive industry where light weight, strong and heat resistant materials are needed for bumpers, dashboards, and interior trims. Additionally, these composites can be used for consumer goods where strong and lightweight materials are needed for various consumer products such as furniture, sporting goods, and appliances. Finite Element Analysis (FEA) was used to explore the properties of the cellulosic composites and the experimental method was used to validate the results of FEA. The injection moulding process was used to fabricate the specimens for this study. The specimens were then characterized for their thermal behavior, morphology, and flexural properties. The thermal properties that were performed were thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Moreover, the morphology of the fabricated samples was examined using the scanning electron microscopy (SEM). The composites were fabricated at filler volume fractions ranging from 0% to 50%. The flexural strength of both the wood powder/PP composites and the hybrid composites were found to be maximum for a filler volume fraction of 40% exhibiting 796.44 MPa and 1692.951 MPa, respectively. The research also noted from TGA that the melting temperature of all the fabricated samples were in the range of 150 °C to 160 °C. The glass transition temperature of neat polypropylene was around −20 °C.

Biobased polyesteramides derived from bisfuranic diamine and aliphatic diesters of varied chain lengths: synthesis and chemical stability

This study presents the development of a series of biobased polyesteramides, labeled as PEAF1–3, via a greener approach, from bisfuranic diamine and commercially available aliphatic diesters of varied chain lengths. The resulting polymers showed reasonable molar masses, in accordance with inherent viscosities ranging between 0.19 and 0.35 dL/g. Evaluation of their thermal properties by thermogravimetric analysis and differential scanning calorimetry showcased excellent thermal stability (Td ,max ≥ 335 °C), amorphous character and low glass transition temperature (Tg ) decreased with the increasing chain length. Moreover, notable finding was the exceptional stability of these polyesteramides against both hydrolytic and oxidative degradation processes. This resistance underscores their potential as highly stable materials, making them promising for various applications where durability and resistance to degradation are crucial.

Thermal and Mechanical Properties of Bio‐Based Polyamide 56/6 Filled with Talc

AbstractPolyamide composites with varying filler concentrations are prepared using the hot melt extrusion method, employing polyamide 56/6 (PA56/6) and modified talc as fillers. Initially, the thermal characteristics of PA56/6 composites (PA56/6‐talc) are examined through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), encompassing parameters such as melting temperature, crystallinity, and decomposition temperature. The hydrophilicity and barrier properties of PA56/6‐talc are assessed using an optical contact angle meter, a water vapor transmission rate tester, and an oxygen transmission rate tester. Furthermore, the mechanical properties of PA56/6‐talc are also scrutinized. The results indicate that PA56/6 exhibits superior hydrophobic, barrier, and mechanical properties, thereby demonstrating its immense potential in garment fabrics and packaging materials.

Assessment of heating rate and mixing ratio on the synergistic effects of co-pyrolysis of pine sawdust and high-density polyethylene

The co-pyrolysis of biomass and plastics presents a promising approach for generating hydrocarbon fuels and high-value chemicals while addressing environmental pollution concerns. This study investigates the pyrolysis process by examining mixtures of pine sawdust (PS) and high-density polyethylene (HDPE) with varying mass proportions and heating rates using analytical methods including thermogravimetric analysis and differential scanning calorimetry (TGA-DSC), thermogravimetry coupled with Fourier transform infrared spectroscopy (TG-FTIR) coupled analysis, pyrolysis gas chromatography-mass spectrometry (Py-GC-MS) and kinetic analysis. The study highlights the impact of heating rate on product distribution, with significant changes observed when the biomass ratio is at 30 %. Moreover, the addition of high-density polyethylene leads to an increase in polyol content in the liquid product. Analysis of product types reveals that plastics act as “hydrogen donors,” supplying hydrogen to biomass during co-pyrolysis, thus reducing oxygen chemicals. Results from the kinetic analysis show that the activation energy for co-pyrolysis is lower than individual pyrolysis, also indicating a synergistic effect. Overall, this research provides insights into the synergistic benefits of co-pyrolysis and establishes a theoretical foundation for advancing co-pyrolysis technology.

Fabrication and characterization of bio-nanocomposite from sweet potato starch and Moringa oleifera leaf extract loaded with carbon quantum dots from Coffea arabica grounds

The study aims to generate and characterize a bio-nanocomposite film derived from sweet potato starch and Moringa oleifera leaf extract and carbon quantum dots (CQDs) derived from Arabica coffee grounds employing the solvent casting method. The effect of various concentrations of CQDs (0–400 ppm) was investigated on the physicochemical properties, UV-barrier, antioxidant properties, and biodegradability of the bionanocomposite (BNC) films. The morphological surface of the bio-nanocomposite was examined using scanning electron microscopy (SEM). Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were performed to evaluate the thermal stability of the samples. Mechanical properties, including tensile strength (TS) and elongation at break (EB), were also assessed. The results show that the incorporation of CQDs with starch-based biofilms had a remarkable impact on the properties of BNC. SEM images confirm the homogeneous structure of the films with slight granulations. Colorimetric analysis indicates the increase in color difference of BNCs as the concentration of CQDs varied. The BNC100 formulation confirmed batter opacity, transparency, and UV-barrier properties while BNC50 possessed significant improvement in tensile, elongation as well as a substantial increase in the melting point. FTIR and XRD analysis confirmed proper chemical interactions among the components within the polymeric structure of the BNC film. In addition, CQD integration has also steadily enhanced the antioxidant properties and biodegradability of BNC films. The fabricated films with CQDs have demonstrated a better quality in terms of optical properties, physical properties, thermomechanical properties, biodegradation rate, and antioxidant behavior that suggest the film's application in food packaging or other relevant fields.

Efficient Recycling and Utilization Strategy for Steel Spent Pickling Solution

Before steel can be utilized, pickling is necessary to remove surface oxidation products. However, as the ferrous ion concentration in the pickling solution increases, the pickling rate significantly diminishes, necessitating the treatment of spent pickling solution (SPS) to mitigate its hazardous effects prior to disposal. Current industrial methods predominantly rely on neutralization and precipitation techniques, which are cost-prohibitive and generate substantial by-products, thus failing to meet environmental protection standards. In this study, a new method, which is based on the formation of FeC2O4·2H2O precipitate in a strong acid solution, is proposed to treat the SPS. Initially, the SPS undergoes a two-step impurity removal process, followed by the controlled addition of oxalic acid dihydrate (H2C2O4·2H2O) to precipitate iron. The resulting precipitate is filtered, washed, and vacuum-dried, and the regenerated acid is recycled back into the pickling tank. When 1 g/10 mL of H2C2O4·2H2O is used, the iron removal rate achieves 60%, and the acidity of the regenerated acid increases by 11.3%. X-ray diffraction pattern (XRD) and thermogravimetric–differential scanning calorimetry (TG-DSC) characterization showed that the precipitate was α-FeC2O4·2H2O, with an average particle size of about 3.19 μm and a purity of 95.24%. This process innovatively achieves efficient recycling of acid and iron resources, offering a potential solution to the industrial challenge of difficult SPS treatment in the steel industry and meeting the urgent need for sustainable development.

Protic ionic Liquids-Water Interactions: A study on 2-Hydroxypropylammonium formate through experimental analysis and computer simulations

In this study, interactions within a mixture of the protic ionic liquid 2-hydroxypropylammonium formate and water were investigated across the entire range of ionic liquid compositions and a wide temperature range from 283.15 K to 333.15 K. This investigation was based on the measurement results of density, viscosity, and electrical conductivity, and was supported by computational simulations. The synthesized ionic liquid was further characterized thermally using Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) techniques. The study focuses on the analysis of excess molar quantities of volume, thermal expansion coefficients, viscosity, and Gibbs energy of viscous flow, aiming to examine the influence of temperature and mixture composition on thermophysical properties. The impact of temperature on the system’s viscosity and Angell’s strength parameter was investigated to assess the influence of the ionic liquid’s content on the system’s structural organization. The dependency of molar conductivity on viscosity was analyzed through the Walden rule. Based on this analysis, the effect of temperature and mixture composition on deviations from the ideal behavior in diluted solutions of strong electrolytes was estimated. Computational molecular dynamics simulations were employed for a more detailed study of the structural organization of the system’s components.

The effects of hardening accelerator on microstructure and mechanical performance of fly ash-cement-based materials using response surface methodology

To enhance the engineering application range of fly ash-cement-based materials (FCM), the combined effects of hardening accelerator on FCM were investigated by using response surface methodology (RSM). Based on a three-factor three-level Box-Behnken design (BBD), the linear, quadratic and interaction relationships between the dosages of calcium chloride (CaCl2), aluminum sulfate (Al2(SO4)3) and triethanolamine (TEA) on the primary properties (setting time, mechanical properties and shrinkage rate) of FCM were discussed. The prediction model was established to determine the optimal ratio of the composite system. The microscopic performance and the mineral fraction of the paste were explored by using X-ray diffraction (XRD), thermogravimetric differential scanning calorimetry (TG-DSC), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Results indicated that the paste performance was affected by the interaction of multiple factors, and the interaction between CaCl2 and Al2(SO4)3 was the most significant. The optimum ratio of paste was 2.81 % CaCl2, 0.75 % Al2(SO4)3 and 0.12 % TEA, achieving a 28 d compressive strength of 40.48 MPa, closely matching the predicted value. The dominant hydration products of the composite cementitious system were C–S–H gel, AFt and Friedel's salt, with changes observed in the morphology of CH. With the prolong of curing age, the hydration products and unhydrated fly ash particles were bonded to each other, so that the slurry maintains a certain strength performance.

Thermal stabilization enhancement of diamond films via boron doping and its antioxidant mechanism

Diamond films possess numerous extraordinary physical and chemical properties, but their high-temperature applications are limited by its poor thermal stability. Herein, we fabricated the undoped microcrystalline diamond (MCD) film and heavy boron-doped diamond (h-BDD-1, 2.94 × 1021 atoms·cm−3; h-BDD-2, 9.10 × 1021 atoms·cm−3) films to investigate the effect of boron doping on the thermal stability of diamond films. A series of evidences, including air annealing experiments, thermogravimetric-differential scanning calorimetry (TG-DSC) analysis, and in-situ ultra-high-temperature confocal laser-scanning microscope (CLSM), demonstrated that the thermal stability of diamond films was obviously enhanced by boron doping. Consequently, the h-BDD-2 film exhibited the best thermal stability with an initial oxidation temperature above 900 °C, which was much higher than that of MCD film (709 °C). By deconvolving the X-ray photoelectron spectra, we believed that the transition of B–C bonds to stable oxy-boron carbide complexes (B4O–C, B3O–C) is the key to improving the thermal stability. These results not only reveal a new antioxidant mechanism of boron-doped diamond films but also pave a way for the application of diamond in high-temperature environments.

Influence of Crucible Types on Thermal Stability Analysis of Li‐Ion Battery Components by Thermogravimetric Analysis–Differential Scanning Calorimetry

Lithium‐ion batteries are widely used in various industrial and consumer applications. One key point is the thermal stability of these batteries regarding safety. Thermogravimetric analysis and differential scanning calorimetry (DSC) are ideal methods to study the thermal properties of differently charged electrode materials without safety issues associated with thermal runaway tests of the complete cell. This study shows a significant relationship between state of charge (SOC) and power released by the electrode material during the heating process. For the utilized cathode material LixCoO2, a linear relationship is apparent between the decomposition temperature and the decomposition energy, enabling estimation of the SOC. The decomposition temperature of differently charged anode material strongly correlates with the selected heating rate. This study reveals substantial dependencies of the measured power on the utilized crucibles, providing a systematic approach to benchmark the impact of crucible type on observed DSC signals during battery component analysis.