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Non-isocyanate polyurethanes (NIPUs) are considered as a class of environmentally-safe polymers that show promising properties, such as chemical and mechanical resistance. An important feature that may limit some important applications is the thermal degradation behavior of NIPUs and their composites and hybrids. Hence, this article comprehensively reviews recent developments in these materials groups, focusing on the thermal stability and degradation routes. Influence of urethane linkage vicinity, molar mass and ratio of carbonate and amine components, and chemical structure on NIPU thermal degradation behavior was discussed. The onset temperature of degradation was found to be mainly influenced by urethane bonds concentration and crosslinking density of NIPU material. Chain length of amine component has also a significant impact on the thermal degradation profile. The incorporation of bio-sourced and nano-scaled additives (carbon- and silica-based nanoparticles) and their impact on thermal stability of NIPU matrix was analyzed, too, and future outlooks were given. [ABSTRACT FROM AUTHOR]

Renewable resources based polymers have been the focus of materials science scientists since they help to protect the environment in addition to reducing the petroleum resources use. Among renewable polymers poly (lactic acid) (PLA) has emerged due to its biodegradable character and proper performance similar to engineering resins, which afford wide field of applications. In this work the thermal degradation of esterified PLA with itaconic acid (PLA ITA) and the biocomposite PLA ITA FLAX was investigated using thermogavimetry (TG) which data were corroborated through Fourier transform infrared spectroscopy (FTIR). Isothermal TGs scans and FTIRs spectra were acquired from 150 to 600°C, collected data evidenced that FLAX improved PLA ITA thermal stability, delaying the decomposition of PLA ITA by up to 100 min at 250°C, ensuring safer processability at higher temperatures. From the deconvolution of the DTG peaks, the peak at lower temperature is suggested to be linked to itaconic anhydride decomposition which undergoes macromolecule dissociation, converting into itaconic anhydride and releasing water and afterwards being converted into citraconic anhydride, while the peak at higher temperature is associated to the thermal degradation of telechelic PLA. Degradation mechanism is proposed, evidenced by changes in the wavelength of CO group under the effect of temperature, as evidenced in TG‐IR spectra. [ABSTRACT FROM AUTHOR]

Hydrogel features can be designed and optimized using different crosslinking agents to meet specific requirements. In this regard, the present work investigates the physico-chemical features of cellulose-based hydrogels, designed by using different epoxy crosslinkers from the same glycidyl family, namely epichlorohydrin (ECH), 1,4-butanediol diglycidyl ether (BDDE), and trimethylolpropane triglycidyl ether (TMPTGE). The effect of the crosslinker's structure (from simple to branched) and functionality (mono-, bi- and tri-epoxy groups) on the hydrogels' features was studied. The performances of the hydrogels were investigated through the gel fraction, as well as by ATR-FTIR, DVS, SEM, DSC, and TG analyses. Also, the swelling and rheological behaviors of the hydrogels were examined. The advantages and limitations of each approach were discussed and a strong correlation between the crosslinker structure and the hydrogel properties was established. The formation of new ether bonds was evidenced by ATR-FTIR spectroscopy. It was emphasized that the pore size is directly influenced by the crosslinker type, namely, it decreases with the increasing number of epoxy groups from the crosslinker molecule, i.e., from 46 ± 11.1 µm (hydrogel CE, with ECH) to 12.3 ± 2.5 µm (hydrogel CB, with BDDE) and 6.7 ± 1.5 µm (hydrogel CT, with TMPTGE). The rheological behavior is consistent with the swelling data and hydrogel morphology, such as CE with the highest Qmax and the largest pore size being relatively more elastic than CB and CT. Instead, the denser matrices obtained by using crosslinkers with more complex structures have better thermal stability. The experimental results highlight the possibility of using a specific crosslinking agent, with a defined structure and functionality, in order to establish the main characteristics of hydrogels and, implicitly, to design them for a certain field of application. [ABSTRACT FROM AUTHOR]

Polybenzimidazoles (PBIs) are recognized for their remarkable thermal stability due to their unique molecular structure, which is characterized by aromaticity and rigidity. Despite their remarkable thermal attributes, their tensile properties limit their application. To improve the mechanical performance of PBIs, we made a vital modification to their molecular backbone to improve their structural flexibility. Non-π-conjugated components were introduced into PBIs by grafting meta-polyamide (MA) and para-polyamide (PA) onto PBI backbones to form the copolymers PBI-co-MA and PBI-co-PA. The results indicated that the cooperation between MA and PA significantly enhanced mechanical strain and overall toughness. Furthermore, the appropriate incorporation of aromatic polyamide components (20 mol% for MA and 15% for PA) improved thermal degradation temperatures by more than 30 °C. By investigating the copolymerization of PBIs with MA and PA, we unraveled the intricate relationships between composition, molecular structure, and material performance. These findings advance copolymer design strategies and deepen the understanding of polymer materials, offering tailored solutions that address thermal and mechanical demands across applications. [ABSTRACT FROM AUTHOR]

The thermal and mechanical stability of amphiphobic anti-corrosion coating is evaluated in this study. The coating was fabricated from functionalized nano Al2O3 and polyvinylidene fluoride (PVDF) and analyzed using FTIR, DSC, TGA, XRD, abrasion and cross-hatched adhesion test analyses. DSC and XRD revealed the presence of multiple crystalline phases of PVDF in the coating which eventually increased the crystallinity and melting temperature. The removal of the CFx chain from alkylsilane occurred at elevated temperatures, which decreased the repellent characteristic. Overall, the coating demonstrated good thermal stability until the temperature of 450°C with the ISO class 2 adhesion. [ABSTRACT FROM AUTHOR]

A plethora of studies in conjugated polymer modification is aimed at improving their physicochemical properties for practical application. Functionalization of polyaniline (PANI) by introducing a substituent on the aromatic ring is an effective way to achieve high solubility. In this regard, this study was focused on the investigation of the thermal stability of three PANI derivatives with ortho-substituents of various structures using thermogravimetric analysis at different heating rates (5, 10, 15, and 20 °C min−1) in a nitrogen atmosphere. The results of TGA and DTG showed that the process of thermal degradation of PANI derivatives proceeded according to a complex multistage mechanism. Using the Coats–Redfern integral method and 10 basic models, activation energies and pre-exponential factors were calculated for three stages of polymer thermal degradation. According to the results, with the highest linear regression coefficient, the second-order reaction model (F2) was the most suitable for the initial period of decomposition, while diffusion (D1, D2, D3) and interfacial (S1, S2) models were suitable for high-temperature stages. All models showed a positive ΔH. The highest ΔG values were obtained using diffusion and interfacial models. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the thermal and pH stability of anthocyanins in black carrot extracts (BCEs) when exposed to a temperature of 90 °C for 6 h. This investigation was conducted with BCEs both in pure form and in the presence of copigments such as mandarin peel extract (MPE), pomegranate peel extract (PPE), and rose petal extract (RPE) in model solutions with varying pH (2.2, 2.8, 3.2, 3.6, 4.2, 4.8, and 5.4). The stability of black carrot anthocyanin (BCA) was assessed based on its ability to withstand the elevated heating temperature and maintain its color intensity under various pH conditions. The results indicated that copigmentation enhanced the pH, color, and thermal stability (to a certain extent) of BCEs. The pH stability was found to be higher in the samples copigmented with MPEs and RPEs. These results suggest that the decline in the monomeric anthocyanin content and higher color density might be due to polymerization and/or copigmentation rather than degradation. The maximum polymeric color was observed in the MPE-copigmented sample (58.05%), followed by the samples copigmented with RPE (52.94%) and PPE (24.61%) at pH 5.4. Moreover, we found that the thermal degradation of black carrot anthocyanins is a unimolecular serial-type reaction involving reactive intermediates. The proposed degradation pathway suggests that the first stages of degradation include the removal of sugar molecules and glycosidic bonds. [ABSTRACT FROM AUTHOR]

Thermal decomposition behavior and kinetics of four kinds of Chinese heritage architectural wood were investigated by thermogravimetric analysis. Experiments were carried out in air atmosphere up to 600°C. The thermal degradation process of historical wood involved a two-step reaction kinetics, consisting of a low-temperature stage (230–370°C) and a high-temperature stage (370–485°C). Distributed activation energies determined using Coats-Redfern method and the first-order model (O1) have optimum fitness compared with nth-order model functions. The lignocellulosic components of white pine and red pine have similar thermal stability, spruce has the slowest combustion rate or best thermal stability, and the reactivity of charcoal and lignin with oxygen of nanmu was higher than that of other three types of historical wood. The activation energy of four historical wood species is lower than that of most fresh wood and varied from 75.10 to 83.39 kJ/mol in the first stage and 10.75 to 15.97 kJ/mol in the second stage. [ABSTRACT FROM AUTHOR]

Reducing the flammability of kapok fiber (KF) is an important strategy to increase its applicability. In this work, the phosphorylation of KF with ammonium dihydrogen phosphate (ADP) was used to reduce its flammability, the conditions of phosphorylation reaction were studied in detail, and the chemical groups, crystalline structure, thermal stability, heat release capability, flammability and charring ability of phosphorylated KF were analyzed. KF showed significantly higher phosphorylation level than cotton, and its phosphorylation greatly depended on ADP and urea dosage, reaction temperature and time, and pH. Urea addition, pH 6, 150 ℃ and 1 h rendered high phosphorylation with acceptable whiteness. Phosphorylated KF exhibited good char-forming, low heat release and excellent flame retardant performances during thermal degradation and combustion as evidenced by thermogravimetric, microcalorimetric, vertical combustion and combustion residue morphology analyses. The residue rate of phosphorylated KF subjected to thermal degradation exceeded 50% in nitrogen, and 25% in air. This investigation demonstrates that phosphorylated KF is an intrinsically flame retardant material. [ABSTRACT FROM AUTHOR]

The article presents the results of experimental study on the effect of additives of silicon oxide nanoparticles, as well as single-walled and multi-walled carbon nanotubes on the colloidal stability and thermal degradation process of hydrocarbon-based drilling fluids. Such a comprehensive study of hydrocarbon-based drilling fluids was carried out for the first time. The effect of the concentration and size of silicon oxide nanoparticles, as well as the type and concentration of nanotubes on the colloidal stability of drilling fluids during thermal aging tests at different temperatures, was investigated. The nanoparticle size varied from 18 to 70 nm, and the concentration ranged from 0.25 to 2 wt.%. Single-walled and multi-walled nanotubes were studied, whose concentration varied from 0.01 to 0.5 wt.%. The thermal aging temperature varied from 30 to 150 °C. According to the results of the investigation, it was shown that the temperature stability of hydrocarbon-based drilling fluids can be significantly improved by adding the above substances. At the same time, it was shown that the use of single-walled nanotubes for thermal stabilization of drilling fluids was several times more effective than the use of multi-walled nanotubes, and tens of times more effective than the use of spherical silicon oxide nanoparticles. [ABSTRACT FROM AUTHOR]

The stability of heterogeneous catalytic systems is critical for their long-term. Therefore, the thermal degradation behaviors of CuO/ZnO supported on octaphenyl and dodecaphenyl polyhedral oligomeric silsesquioxane and silsesquioxane were investigated. The presence of the metal oxides does not interfere with the degradation mechanisms up to the temperature of 450 °C. After that temperature, the metal oxides accelerate the degradation rate of the supports. Irreversible thermal events, including molecular relaxation and crystal rearrangement, with low transition energy, were observed using differential scanning calorimetry. In all cases, the thermal analysis revealed complex behaviors. The crystal structure of both supports is destroyed in the oxidative atmosphere at 900 °C but partially destroyed in the nitrogen atmosphere. The vibrational frequencies of the residues in the inert and oxidative atmosphere showed after 500 °C the deformation of the Si–O peak due to intercage linkages formation. [ABSTRACT FROM AUTHOR]

Purpose: Affinisol HPMC HME is a new popular form of hypromellose specifically designed for the hot melt extrusion and 3D printing of pharmaceutical products. However, reports of its thermal stability include only data obtained under inert N2 atmosphere, which is not consistent with the common pharmaceutical practice. Therefore, detailed investigation of its real-life thermal stability in air is paramount for identification of potential risks and limitations during its high-temperature processing. Methods: In this work, the Affinisol HPMC HME 15LV powder as well as extruded filaments will be investigated by means of thermogravimetry, differential scanning calorimetry and infrared spectroscopy with respect to its thermal stability. Results: The decomposition in N2 was proceeded in accordance with the literature data and manufacturer's specifications: onset at ~260°C at 0.5°C·min−1, single-step mass loss of 90–95%. However, in laboratory or industrial practice, high-temperature processing is performed in the air, where oxidation-induced degradation drastically changes. The thermogravimetric mass loss in air proceeded in three stages: ~ 5% mass loss with onset at 150°C, ~ 70% mass loss at 200°C, and ~ 15% mass loss at 380°C. Diffusion of O2 into the Affinisol material was identified as the rate-determining step. Conclusion: For extrusion temperatures ≥170°C, Affinisol exhibits a significant degree of degradation within the 5 min extruder retention time. Hot melt extrusion of pure Affinisol can be comfortably performed below this temperature. Utilization of plasticizers may be necessary for safe 3D printing. [ABSTRACT FROM AUTHOR]

In this study, thermal stability and degradation kinetics of the phenolics of the aqueous fenugreek leaf extracts were determined. Thermal degradations of total phenolics, total flavonoids, antioxidant activity and total saponins of the fenugreek leaf extracts were examined at different pH values (3.0, 6.0 and 9.0) and different temperatures (60, 70, 80, 90 and 100°C) for time. Moreover, degradation kinetics of the total phenolics were explained by first-order reaction kinetics. Half-life values, free energy and activation energy of the extracts for total phenolic compounds were calculated. According to the results, the extracts showed better thermal stability at pH 3.0 than the other pH values at the selected temperatures concerning total phenolics, total flavonoids, antioxidant activity and total saponins. The degradation of the total phenolics, total flavonoids and antioxidant activity followed similar trends. The phenolic extract of the fenugreek leaves had high thermal stability. The extract had antioxidant activity despite applying eight hours of thermal treatment at 100°C. Kinetic constants (k) were 0.151-0.435 h-1, 0.181-0.491 h-1 and 0.197-0.634 h-1 at pH 3.0, pH 6.0 and pH 9.0, respectively. Activation and free energy values for the degradation of fenugreek phenolics were calculated in the range of 26.02-29.97 kJ/mol and 109.31-120.07 kJ/mol, respectively. The half-life values of total phenolics treated at 60-100°C were 1.59-4.59 h, 1.41-3.83 h, and 1.09-3.52 h for pH 3.0, 6.0 and 9.0, respectively. [ABSTRACT FROM AUTHOR]

In the present study, poly(butylene succinate) (PBSu) and its bionanocomposites containing 1, 2.5, and 5 wt.% biochar (MSP700) were prepared via in situ melt polycondensation in order to investigate the thermal stability and decomposition mechanism of the materials. X-ray photoelectron spectroscopy (XPS) measurements were carried out to analyze the surface area of a biochar sample and PBSu/biochar nanocomposites. From XPS, it was found that only physical interactions were taking place between PBSu matrix and biochar nanoadditive. Thermal stability, decomposition kinetics, and the decomposition mechanism of the pristine PBSu and PBSu/biochar nanocomposites were thoroughly studied by thermogravimetric analysis (TGA) and pyrolysis–gas chromatography/mass spectrometry (Py−GC/MS). TGA thermograms depicted that all materials had high thermal stability, since their decomposition started at around 300 °C. However, results indicated a slight reduction in the thermal stability of the PBSu biochar nanocomposites because of the potential catalytic impact of biochar. Py−GC/MS analysis was employed to examine, in more detail, the thermal degradation mechanism of PBSu nanocomposites filled with biochar. From the decomposition products identified by Py−GC/MS after pyrolysis at 450 °C, it was found that the decomposition pathway of the PBSu/biochar nanocomposites took place mainly via β-hydrogen bond scission, which is similar to that which took place for neat PBSu. However, at higher biochar content (5 wt.%), some localized differences in the intensity of the peaks of some specific thermal degradation products could be recognized, indicating that α-hydrogen bond scission was also taking place. A study of the thermal stability and decomposition pathway of PBSu/biochar bionanocomposites is crucial to examine if the new materials fulfill the requirements for further investigation for mulch films in agriculture or in electronics as possible applications. [ABSTRACT FROM AUTHOR]

Understanding the oxidative and thermal degradation of CO2 sorbents is essential for assessing long‐term sorbent stability in direct air capture (DAC). The potential degradation pathway of imidazolium cyanopyrrolide, an ionic liquid (IL) functionalized for superior CO2 capacity and selectivity, is evaluated under accelerated degradation conditions to elucidate the secondary reactions that can occur during repetitive absorption‐desorption thermal‐swing cycles. The combined analysis from various spectroscopic, chromatographic, and thermal gravimetric measurements indicated that radical and SN2 mechanisms in degradation are encouraged by the nucleophilicity of the anion. Thickening of the liquid and gas evolution are accompanied by 50 % reduction in CO2 capacity after a 7‐day exposure to O2 under 80 °C. To prevent long exposure to conventional thermal heating, microwave (MW) regeneration of the CO2‐reactive IL is used, where dielectric heating at 80 and 100 °C rapidly desorbs CO2 and regenerates the IL without any measurable degradation. [ABSTRACT FROM AUTHOR]

A kind of ceramifiable rubber-based composite with high-temperature resistance and flame retardancy was prepared by adding silicate glass frits (SGFs) and ammonium polyphosphate (APP) to silicone rubber matrix. The ceramifiable performance was further improved by enhancing thermal stability of the composite through incorporating organo-modified montmorillonite (OMMT). The high-temperature resistance and ceramifiable performance of the ceramifiable silicone rubber-based composite under various pyrolysis conditions were tested. For the fired specimen of silicone rubber/SGF/APP/OMMT, its flexural strength decreased from 4.80 to 3.23 MPa as the heating rate increased from 5 to 20 K min–1, which means that lower heating rate is more favorable to form a compact and dense ceramic body. The influence of thermal stability on the ceramization effects of the ceramifiable silicone rubber-based composite was quantitatively analyzed from the perspective of thermal degradation kinetics based on the Kissinger, Kissinger--Akahira--Sunose, and Flynn--Wall--Ozawa methods. The results show that the pyrolysis activation energy Ea of the composite has a certain relationship with the ceramifiable performance. The better the thermal stability of the composite is, the higher the Ea is and the better the ceramifiable performance is. The Ea increased with the process of ceramization reaction of the composite. The reliability of the regular relation between combustion intensity of material itself, external ablation conditions, and ceramization effect was also verified through cone calorimetry and scanning electron microscope analysis. These results are helpful in preparing ceramifiable polymer composite, which possesses high-temperature resistance. [ABSTRACT FROM AUTHOR]

Sr 2 Si 5 N 8 :Eu2+ (258) phosphor has attracted much attention due to its excellent red emission properties. However, its poor thermal stability hinders its further development in electronic display devices. Therefore, it is important to solve this problem in order to produce stable and long life-time WLED devices. In this work, a 258 phosphor was synthesized by a simple solid-phase reaction method, which was then coated by an ultrathin carbon layer by chemical vapor deposition. The carbon-coated powders were further annealed in N 2 atmosphere at a high temperature to trigger the carbothermal reaction. On the one hand, the carbothermal reaction resulted in the removal of oxygen in the phosphor particle by a part of the carbon on the surface, which reduced the oxidation of both the luminescent centers and the host lattice. On the other hand, the remaining carbon crystallized, forming a graphene-like multilayer that protected the phosphor particle from the penetration of the external oxygen. This eventually resulted in a significant improvement of the thermal stability and oxidation resistance of the phosphor. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the stability and heat resistance of extra premium olive oil. The study material consisted of six extra virgin olive oils (EVOO) obtained from Spain. Four samples were single-strain olive oils: Arbequina, Picual, Manzanilla, and Cornicabra. Two samples were a coupage of Arbequina and Picual varieties: Armonia (70% Arbequina and 30% Picual) and Sensation (70% Picual and 30% Arbequina). Olive oil samples were heated at 170 °C and 200 °C in a pan (thin layer model). In all samples, changes in indexes of lipid nutritional quality (PUFA/SFA, index of atherogenicity, index of thrombogenicity, and hypocholesterolemic/hypercholesterolemic ratio), changes in tocopherol, total polar compounds content, and triacylglycerol polymers were determined. Heating olive oil in a thin layer led to its degradation and depended on the temperature and the type of olive oil. Increasing the temperature from 170 to 200 °C resulted in significantly higher degradation of olive oil. At 200 °C, deterioration of lipid nutritional indices, total tocopherol degradation, and formation of triacylglycerol polymers were observed. A twofold increase in the polar fraction was also observed compared to samples heated at 170 °C. The most stable olive oils were Cornicabra and Picual. [ABSTRACT FROM AUTHOR]

Polycarbonate (PC) /graphene nanocomposite was prepared using multilayer graphene (MLG) with loadings of 0.5, 1, and 3 wt% via melt mixing process. Morphological, structural, and thermal properties of the PC/MLG nanocomposites are investigated to look into the influence of MLG on the nanocomposite. A significant increase (∼6.4°C) in glass transition temperature is observed upon the addition of 3 wt% of MLG into the polycarbonate matrix. This increase in glass transition temperature may be due to the interaction between the MLG and polycarbonate polymer matrix. The specific heat capacity of pure PC and PC/MLG nanocomposites varies linearly with temperature below their glass transition. Upon the addition of MLGs, the overall thermal stability of PC/MLG nanocomposites increases with MLG loadings. A maximum increase about 29.23°C in T onset of thermal decomposition is observed in PC/MLG nanocomposite having 3 wt% of MLG loading. The activation energy (Ea) of thermal decomposition is also calculated by kinetic analysis of thermal decomposition of the PC/MLG nanocomposites using Horowitz–Metzger and Broido's methods. [ABSTRACT FROM AUTHOR]

In this work, the effect of functionalized hydroxyapatite (HAp-g-PEG) on the thermal degradation behaviour and flammability of polyoxymethylene copolymer (POM_C) was investigated. Organic–inorganic hybrid additive, obtained by grafting of poly(ethylene glycol) on HAp surface using 1,6-hexamethylene diisocyanate as a linker, has been incorporated into POM matrix through an extrusion process. TG analyses show that the incorporation of HAp-g-PEG into POM_C leads to the significant improvement in the thermal stability of the polymer matrix. This is an important finding as POM, being an engineering polymer, suffers from a relatively low thermal stability that limits processing options to develop advanced composite materials. Based on TG results kinetic parameters of the thermal degradation process using Friedman isoconversional method and nonlinear regression method have been calculated; an increase in activation energy of POM degradation process after incorporation of HAp-g-PEG has been found. Thermoanalytical analyses (TG-FTIR/MS) show that incorporation of HAp-g-PEG has no significant effect on the composition of the thermal degradation products. Flammability investigations showed small effect of HAp-g-PEG 600 on the burning time and rate, however, there was a significant reduction in the amount of dripping during the material's burning process. [ABSTRACT FROM AUTHOR]

Thermal degradation of water-based muds is a common occurrence while drilling wells in elevated to high temperature and pressure formations. Mud breakdown is usually accompanied by changes in the composition of the mud and subsequent loss of properties required by the mud to perform its functions optimally. Water-based muds are cost effective and environmentally compatible but degrade at higher temperatures. Thus, the need for continuous research for water-based muds with improved performance that can meet the technical requirements of drilling at higher temperatures. This study investigated the effects of two nanomaterials, Multi-Walled Carbon Nanotubes and Iron (II, III) Oxide (Fe₃O₄) on the filtration and rheological properties of WBMs at elevated temperature and pressure (150°C and 500 psi). Conventional additives were used with the nanomaterials at 0.2, 0.5 and 0.8 wt% concentrations to prepare the nano-mud systems which were aged in a static oven at 150°C for 16 hours before conducting filtration tests at 500 psi and 150°C and rheological tests at ambient temperature and pressure. The morphology of the filter cake samples was investigated using SEM and the permeability was obtained using an existing correlation. The nanomaterials enhanced the filtration properties with carbon nano tube muds exhibiting considerable improvement at all concentrations. The highest improvement was obtained with 0.8 wt% Multi-Walled Carbon Nanotubes with a 15.79 % reduction in filtrate volume relative to the base mud while a slight improvement was achieved with 0.2 wt% Fe₃O₄. The carbon nano tube mud systems also gave lower filter cake thicknesses and permeability values relative to the base mud and the Fe₃O₄ system. The nano-mud samples exhibited lower rheological properties relative to the base mud for all the measured parameters (10-second gel strength, 10-minute gel strength, yield point and plastic viscosity) indicating improved dispersion of the mud particles. The results obtained indicate the suitability of these nanomaterials for the modification of water-based mud properties at elevated temperature and pressure conditions. [Display omitted] • HPHT well drilling often faces fluid loss issues, commonly addressed with expensive and environmentally harmful OBMs. • Cheaper and more eco-friendly WBMs degrade quickly under HPHT conditions. • This study used nanomaterials (MWCNTs, Fe3O4) to improve WBM filtration at high temperature and pressure. • MWCNTs showed significant promise, reducing filtrate volume and enhancing filtration properties for high-temperature applications. [ABSTRACT FROM AUTHOR]

The article presents the results of experimental study on the effect of additives of silicon oxide nanoparticles, as well as single-walled and multi-walled carbon nanotubes on the colloidal stability and thermal degradation process of hydrocarbon-based drilling fluids. Such a comprehensive study of hydrocarbon-based drilling fluids was carried out for the first time. The effect of the concentration and size of silicon oxide nanoparticles, as well as the type and concentration of nanotubes on the colloidal stability of drilling fluids during thermal aging tests at different temperatures, was investigated. The nanoparticle size varied from 18 to 70 nm, and the concentration ranged from 0.25 to 2 wt.%. Single-walled and multi-walled nanotubes were studied, whose concentration varied from 0.01 to 0.5 wt.%. The thermal aging temperature varied from 30 to 150 °C. According to the results of the investigation, it was shown that the temperature stability of hydrocarbon-based drilling fluids can be significantly improved by adding the above substances. At the same time, it was shown that the use of single-walled nanotubes for thermal stabilization of drilling fluids was several times more effective than the use of multi-walled nanotubes, and tens of times more effective than the use of spherical silicon oxide nanoparticles.

Hydrogenated natural rubber (HNR) was prepared by diimide reduction of natural rubber (NR) latex and characterized by FT‐IR, 1H NMR and TG‐DTG. The thermal degradation kinetic models of HNR were studied under a nitrogen atmosphere by TG‐DTG. Achar and Coats–Redfern methods were used to study the non‐isothermal kinetics models change during the thermal degradation process of NR after hydrogenation. The results indicated that HNR with 34.69% and 63.74% hydrogenation degree were prepared. A one‐stage pyrolysis pathway could be observed from all the TGA curves which were shifted to higher degradation temperatures with the rise of saturation degree. The similar activation energies obtained by both Coats–Redfern and Achar methods confirmed that the kinetics calculation was accurate. The results showed the best‐fit models of the samples with the highest regression coefficient values (R2 > 0.90) were chemical reaction models. The reaction order was three (N3) in NR case and the corresponding mechanism functions were g(α) = [(1‐α)−2–1]/2, f(α) = (1‐α)3. The reaction order was two (N2) when it came to HNR with hydrogenation degree of 34.69%. The most probable mechanism functions were g(α) = (1‐α)−1–1, f(α) = (1‐α)2. As the degree of hydrogenation increased to 63.74%, the reaction order best‐fit changed to one (N1) which was proved to be the same as the ethylene‐propylene diene rubber samples. And the mechanism functions were g(α) = −ln(1‐α), f(α) = 1‐α. The thermal degradation models of polymers was closely related to the structure. And the structure effects affected the degradation behavior as well as the thermal properties of polymers. [ABSTRACT FROM AUTHOR]

Stability of antioxidant compounds (AC) is always a challenging aspect in the food industry. AC, by nature, can be easily degraded under exposure of different parameters, predominantly high temperature during food processing. The thermal degradation of AC greatly impedes their nutritional values. However, it is rather surprising that only little attentions are paid concerning the thermal degradation of AC. Therefore, it is of great interest to describe the potential preservation approaches that reduce the thermal degradation rate of the AC. This review presents the effects of parameters affecting the degradation of AC, as well as an update of recent studies focused on the modeling of thermal degradation kinetics of AC. Our efforts encompass the discussion of numerous formulation strategies to improve the thermal stability of AC. In particular, literature compiled in this review highlight the potential of using various formulation strategies like emulsion, cyclodextrin, liposome, hydrogel, solid lipid nanoparticles, and natural deep eutectic solvent to effectively preserve the AC from thermal degradation. These technologies are efficient and reliable in improving the thermal stability of AC. Interestingly, the use of natural deep eutectic solvent holds great promise in enhancing the thermal stability of AC and its application in stabilizing the AC shall be further explored in the future. [ABSTRACT FROM AUTHOR]

Molecular simulations based on reactive force-fields (ReaxFF) have been applied as a powerful tool for exploring the dynamics evolution of complex carbonaceous materials. A comprehensive review of the thermal degradation reactions of renewable and nonrenewable carbon precursors at different conditions is presented, aiming at gaining molecular insights on mitigating heavy carbonaceous deposition in undesirable scenarios using molecular simulation tools, while providing some perspectives and future directions on the subject. The review is divided in three main interconnected areas: (i) overview on the implementation of ReaxFF simulations, structural extraction techniques and microstructural characteristic properties of carbon-based materials, followed by (ii) proposed biomass, bio-oil, and bio-fuel reaction mechanisms from which, the tendency of coke and char formation is tackled. Finally, (iii) understanding nonrenewable coal, soot, coal char, and petroleum derivatives (petcoke) carbonaceous materials reactivity under high-temperature thermochemical reactions. A critical discussion is presented on the effects of temperature and functional groups on the structural evolution of large-scale atomistic structures, initial ring cleavage reactions, along with the generated products yields and characteristics. Suggested improvements in the ReaxFF implementation methodology and parametrization approach are made, followed by future directions on incorporating catalytic surfaces for tackling bio-oil upgrading in regards to coke formation and deposition. [Display omitted] • Overview of Reactive Force Field simulations of carbon-based materials. • Structural extraction techniques and microstructural characteristic of carbon. • Molecular insights on mitigating undesirable heavy carbonaceous deposition. • Temperature effect on the structural evolution, reactions and generated products. • Future directions to study surface reaction pathways and coke deposition characteristics. [ABSTRACT FROM AUTHOR]

The effects of heat stabilizer systems on the thermal stability and processability of self‐made vinylidene chloride‐methyl acrylate copolymer (PVDC‐MA) film were investigated via accelerated aging test, Congo red test, FTIR, DMA, and TG‐FTIR. These results displayed that CaSt2/ESO performed excellently in synergistic inhibition of PVDC‐MA thermal degradation. Especially, when the mass ratio of CaSt2/ESO was 1.5:1.5, the static thermal stability time of PVDC‐MA was increased from 14.5 to 46.5 min. The kinetic calculation results also verified this point. Compared with pure PVDC‐MA, the average apparent activation energy (Ēa) of thermal degradation reaction of PVDC‐MA stabilized by CaSt2/ESO enhanced from 144.1 to 169.7 kJ mol−1 (α0 ≤ 0.1), indicating that the thermal stability of PVDC‐MA in the initial thermal degradation stage was dramatically improved by CaSt2/ESO. Moreover, the mechanism of the effect of CaSt2/ESO on PVDC‐MA in the initial thermal degradation stage was further explored by the generalized master plot methods. The kinetic analysis result suggested that under the synergistic effect of CaSt2/ESO, the mechanism model followed by the degradation of PVDC‐MA changed essentially (the three‐dimensional diffusion thermal degradation mechanism transformed into two‐dimensional diffusion). [ABSTRACT FROM AUTHOR]

Kinetic study of the pyrolysis of waste plastic is crucial in the design of an efficient and predictable thermochemical conversion system amidst the huge amount of plastic waste being rejected daily. Here, the chemical kinetics of cross-linked polyethylene under pyrolysis condition is conducted. The thermal degradation of the cross-linked LDPE/Si-XLPE was investigated under two different conditions: dynamic and isothermal heating. Moreover, two popular models of Kissinger and Flynn–Wall–Ozawa were used to infer the activation energy and pre-exponential constant during the dynamic heating at different heating rates. The isothermal conditions were tested at four different temperatures and reaction times based on the Arrhenius kinetic parameters. Thermo-gravimetric results showed the main region of weight loss occurs between 450 and 480 °C which corresponds to the highest conversion rate. The computed activation energies were 290.26 kJ/mole and 287.56 kJ/mole for Kissinger and Flynn–Wall–Ozawa models, respectively. The dynamic heating produced slightly different values than the one obtained from isothermal heating. This is because the kinetic parameters are highly dependent on the reaction time. These results suggest that Si-XLPE, which is commonly used in the cable industry, follows a similar behavior to the LDPE. This was demonstrated by the detailed analysis of the composition, melting point, thermal stability and thermal degradation. [ABSTRACT FROM AUTHOR]

This is the first study investigating how polycarbodiimide (PCDI) delays thermal degradation of poly(lactic acid)/natural rubber blends (PLA/NR) during the preparation of PLA/NR masterbatches (MB) and PLA/MB compounds for the film blowing process. The PCDI concentration used in this work was from 0 to 1 wt%. The torque plastograms, FTIR, and 1H-NMR spectra indicated the successful chain extending reaction between the PCDI carbodiimide group and the PLA carboxyl group, and there was no reaction with NR domains. The reaction increased the PLA/MB compounds' viscosity and improved processability and mechanical properties of PLA/MB blown films. The optimal PCDI content for the highest melt strength, film blowing stability, and mechanical properties was at 0.25 wt% PCDI. Undesirable gel spots were observed in the PLA/MB blown film at PCDI concentrations higher than 0.5 wt%. [ABSTRACT FROM AUTHOR]

The thermal stability of molybdenum oxide (${\text{MoO}}_{x)}$ -based carrier selective contact silicon solar cells (Ag/ITO/MoOx/n-Si/LiFx/Al) is investigated under ambient annealing conditions for different time durations. The devices remain stable up to 150 °C for 15 and 30 min of annealing. However, at 200 °C, the cells degrade with a decrease in the fill factor and open-circuit voltage ($V_{{\text {oc}}}$); the degradation rate is significant at 30 min. The illumination-dependent $V_{{\text {oc}}}$ study has indicated the charge transport barrier at the MoOx/c-Si interface in a degraded cell. The dark current density-voltage analysis of the degraded cells has also shown charge carrier recombination and series resistance at low- and high-forward bias conditions, respectively. To identify the device degradation with the temperature, ITO/MoOx and MoOx/c-Si interfaces are analyzed in terms of contact resistivity ($\rho _{c}$) using extended transfer length method (ETLM). After annealing at 200 °C, a significant increase in $\rho _{c}$ of the MoOx/c-Si interface (from ~17 to $\sim 385~\text{m}\Omega $ -cm2) is observed in comparison to the ITO/MoOx interface (from ~16.5 to $\sim 39~\text{m}\Omega $ -cm2), reflecting the crucial role of MoOx/c-Si junction in cell degradation. The thermal degradation of the MoOx/c-Si interface is due to a decrease in the MoOx film’s work function (WF) upon annealing, which creates a transport barrier for charge carriers. The reduction in the MoOx WF results in misalignment of c-Si’s valence band and MoOx’s conduction band, leading to inefficient carrier transport through band-to-band tunneling, which is also confirmed from the numerical simulations. [ABSTRACT FROM AUTHOR]

This article presents the synthesis of new derivatives of octa(3‐thiopropyl)silsesquioxane (SSQ‐8SH) via thiol‐ene reaction with simple olefins bearing alkyl groups as well as methoxysilyl, substituted aryl or fluoroalkyl groups. All products were characterized by 1H NMR, 13C NMR, 29Si NMR, FTIR, GPC, MALDI‐TOF‐MS, as well as thermal analysis (TGA) to confirm their structures, purity and thermal stability, and finally give some insight into their thermal degradation pathway. In some of the structures obtained, the T5% values take place at high temperatures and are close to 230 °C. The thiol‐ene reaction allowed to obtain 7 new compounds with high yield (>92 %), no by‐products and in a relatively short time (24 h). All products are characterized by high conversion >99 %. New derivatives can find potential use as modifiers of plastics to improve their certain properties for example hydrophobicity or thermo‐oxidative stability. [ABSTRACT FROM AUTHOR]

A thermogravimetric study of poly(ethyl cyanoacrylate) nanofibers was carried out at five heating rates with a linear increase in the temperature in a nitrogen atmosphere. The data provided by the thermogravimetric study were used to evaluate the kinetics of the degradation process using three isoconversional methods. Considering that the kinetic parameters of the process depend on the reaction mechanism, various approaches were applied in order to determine the most probable mechanism function. In this respect, the mechanism of thermal degradation of poly(ethyl cyanoacrylate) is a phase boundary reaction with cylindrical symmetry (F0.5 function) as demonstrated by the z(α) master plots method, iso‐temperature method and isoconversional method. On their basis, the values of the kinetic triplet (Ea, A and the shape of the most appropriate f(α) function) of the process were obtained, and subsequently the thermodynamic functions of the activated complex formation were calculated. The thermal stability of the polymer was predicted according to the integral procedure decomposition temperature. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the stability and heat resistance of extra premium olive oil. The study material consisted of six extra virgin olive oils (EVOO) obtained from Spain. Four samples were single-strain olive oils: Arbequina, Picual, Manzanilla, and Cornicabra. Two samples were a coupage of Arbequina and Picual varieties: Armonia (70% Arbequina and 30% Picual) and Sensation (70% Picual and 30% Arbequina). Olive oil samples were heated at 170 °C and 200 °C in a pan (thin layer model). In all samples, changes in indexes of lipid nutritional quality (PUFA/SFA, index of atherogenicity, index of thrombogenicity, and hypocholesterolemic/hypercholesterolemic ratio), changes in tocopherol, total polar compounds content, and triacylglycerol polymers were determined. Heating olive oil in a thin layer led to its degradation and depended on the temperature and the type of olive oil. Increasing the temperature from 170 to 200 °C resulted in significantly higher degradation of olive oil. At 200 °C, deterioration of lipid nutritional indices, total tocopherol degradation, and formation of triacylglycerol polymers were observed. A twofold increase in the polar fraction was also observed compared to samples heated at 170 °C. The most stable olive oils were Cornicabra and Picual.

The advent of space exploration and high‐speed civil transport has prompted the development of polymeric materials that can endure extreme environments. Cyanate ester (CE) is a commonly used thermoset matrix for high‐temperature applications in aerospace and defense applications. CE has high glass transition temperature (>200 °C), low moisture absorption, low coefficient of thermal expansion and is extremely thermally stable. Various additives have been reported in the literature to improve thermal stability of the matrix further to prolong the life of parts manufactured from CE. In this review, we survey various inorganic additives based on silica, clay, boron and phosphorus reported in the literature to improve the thermal properties of CE. We also discuss the thermal stability improvement mechanisms for these CE–inorganic hybrids. © 2022 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

To study the thermal stability of ethylene/vinyl acetate/vinyl alcohol (EVA‐OH) composite with filler particles, systematic thermogravimetric analysis (TGA) investigation was conducted in both nonisothermal and isothermal modes. The effect of polymer concentration on the aging behavior of EVA‐OH was investigated in the nitroplasticizer (NP) environment. Fourier transform infrared spectroscopy was used to probe chemical structural changes in the EVA‐OH polymer before and after thermal aging. The results suggest that filler addition accelerates the rate of NP exudation out of the EVA‐OH composites and deteriorates the thermal stability of NP at moderate temperatures (up to 70°C). The degradation of NP, in turn, accelerates the degradation of EVA‐OH polymer in its composite form through oxidation and hydrolysis indicating the importance of antioxidants in such phase blends. [ABSTRACT FROM AUTHOR]

To improve thermal, mechanical and adhesion properties, epoxy resin was modified with methyl phenyl silicone (MPS), acrylonitrile butadiene styrene (ABS) and graphene oxide (GO). In order to increase compatibility and stability, MPS intermediate was grafted on epoxy resin through condensation reaction. Transmission electron microscopy images showed well dispersion of GO particles in the system proving successfully preparation of the MPS grafted epoxy/ABS/GO nanocomposite. Single lap shear strength for steel‐epoxy/carbon fiber composite joint in sample containing 15% MPS and 2% ABS improved up to 108% compared to neat epoxy. Such an improvement occurred when only 5% MPS, 2% ABS and 0.1% GO were used showing GO could decrease required content of modifiers in this case. Tensile strength of sample containing 5% MPS and 2% ABS was 49.89 MPa and it reached 55.23 MPa by adding 0.1% GO while it was 37.12 MPa in pure epoxy. Nanocomposite modified sample had a residual char of 20 wt%. at 600°C and increment of 30°C in initial degradation temperature and 7°C in maximum degradation temperature compared to pure epoxy. These finding beside 23% increasing in calculated activation energy using Kessinger's and FWO method's proved significantly improved thermal stability of modified epoxy resin. Scanning electron microscope images of fractured surface of specimens showed micro size domains obtained by phase separation cause toughness improvement and crack energy absorption. [ABSTRACT FROM AUTHOR]

Thermal stability and kinetics of thermolysis of postconsumer milk containers made of high-density polyethylene (PC-HDPE) and filament rods extruded from them (HDPE-F) were examined by thermogravimetric analysis (TGA) with six linear temperature programs under a stream of nitrogen. The total weightloss of each sample took place in a one-step decomposition to volatiles at the heating rates, β = 1, 10, 25, 50, 70, and 100 Kmin-1. The values of initial decomposition temperature, the temperature at the maximum thermal degradation rate, and the maximum rate of decomposition were increased by increasing the heating rate as was the expectation. The isoconversional method was used to evaluate the fundamental kinetic parameters, the activation energy barrier (Ea), the Arrhenius pre-exponential factor (A), and the mechanism of the reaction, f(α). The values of Ea were independent of the model and heating rate, as was expected. However, the values of A depended on the model and the extent of reaction (α). The values of the Ea of PC-HDPE initiated at 171 kJ/mol at α = 0.05 and it increased to 207 kJ/mole at α = 0.95. The values of Ea of the HDPE-F rod were relatively constant for all α values, being 227 ± 3 kJ/mol. It was justified by the absence of easily volatilized substances in the HDPE-F. Knowledge of the thermal stability and decomposition kinetics of the starting materials (PC-HDPE) and the product (HDPE-F) is important in the context of thermochemical conversion processes aimed at the use of PC-HDPE as raw materials for recycling, upcycling, and down-cycling for objects used under room conditions. [ABSTRACT FROM AUTHOR]

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In modern AC technologies, improving the power efficiency of soft magnetic core materials is a key factor. Powder metallurgy offers a promising alternative for these applications: Soft Magnetic Composites are compacted iron-based powders, each iron particle being electrically insulated from its neighbours by a superficial layer. Accordingly, the thermal stability of the insulating layers used plays an essential role, because the stresses and defects introduced by pressing must be relieved by heat treatment. The thermal stability of FePO4, which is a common insulating barrier, is limited. In the present study, the degrading mechanism was investigated using a mixture of high purity iron powder and FePO4·2H2O. The samples were characterised using a wide variety of analytical methods (DTA/TG, ATR-IR, XRD and XPS). The results show that a ferrothermal reduction takes place, the base material of SMCs – metallic Fe – acting as a reducing agent. [ABSTRACT FROM AUTHOR]

A study on the thermal stability and kinetic parameters of an Octol formulation stockpiled for prolonged period a 20 year under natural environment conditions was investigated. The thermal stability of the naturally aged was studied by an employing thermogravimetry and differential scanning calorimetry methods and compared with freshly prepared Octol formulation. The results showed that the thermal stability did not significantly vary for aged Octol samples. The kinetic parameters of aged and freshly prepared Octol samples were also studied by means of the Kissinger and isoconversional Kissinger–Akahira–Sunose (KAS) methods. The values of apparent activation energy derived from the Kissinger method using DSC data for aged and fresh samples were obtained around 228.8 and 234.4 kJ mol‒1, respectively. The isoconversional KAS method was also used for computation of the activation energy at different values of conversion for two stages of thermal degradation using TGA data. The determined average activation energy for the first stage was obtained around 88.9 ± 4.1 kJ mol−1 for aged and 94.6 ± 6.5 kJ mol−1 for fresh sample, while average activation energy for the second stage was obtained 212.7 ± 14.5 kJ mol−1 and 218 ± 14 kJ mol‒1 for aged and fresh Octol formulations, respectively. These values were found to be consistent and close to those obtained from the Kissinger method. These results indicated that there was no any significant change in the kinetic parameters for aged and fresh samples. The pre-exponential factor for different values of conversion was also determined by the use of the so-called compensation effect. Conversion of aged and fresh samples using the kinetic parameters was found to be in good agreement with the experimental conversion data, and the maximum error limit was observed to be 8.0% between experimental and predicted conversion. [ABSTRACT FROM AUTHOR]

The thiol-ene (TE) polymerization systems have gained a lot of interests from industry and researchers in the last years. A phosphorus-silicon containing flame retardant DOPO-V was synthesized in this study, and the effect of DOPO-V on the flame retardancy of thiol ene was confirmed by cone calorimetry measurement. Moreover, the thermal stability of TE/DOPO-V (FRTE) composite was investigated by the thermogravimetric method under dynamic conditions (50–600°C) in nitrogen atmosphere. Moreover, kinetic parameters were calculated by the Kissinger and Flynn-Wall-Ozawa methods. It was observed that the activation energy for the FRTE degradation was slightly higher than that of pure TE. This was attributed to the fact that DOPO-V could further react with the TE matrix to form a complex and stable phosphorus-silicon containing char layer. Thus, the flame retardancy of FRTE/DOPO-V was higher than that of pure TE. By using both methods approximately equal values of activation energy were obtained. [ABSTRACT FROM AUTHOR]

A heterocyclic meta-aramid fiber containing benzimidazole structure was prepared by the low-temperature polycondensation of m-phenylenediamine, 2-(4-aminophenyl)-5-benzimidazole, and isophthaloyl dichloride, followed by dry-jet wet spinning. The structure and properties of the heterocyclic modified meta-aramid (h-aramid for short) were explored and compared with poly(isophthaloylmetaphenylene diamine) (m-aramid for short). H-aramid exhibits excellent spinnability. The surface of the fiber is smooth and even, with a partially ordered structure. Mechanical properties, thermal resistance, and flame retardant of h-aramid are significantly enhanced as the introduction of benzimidazole can not only increase the rigidity of molecular chains but also strengthen hydrogen bonds and act as physical crosslinking points. The strength and modulus of h-aramid are up to 0.84 GPa and 16.66 GPa, respectively, with an elongation at break of 20%. The glass transition temperature and melting temperature of h-aramid reach 302°C and 356°C, respectively, about 30°C and 40°C higher than that of m-aramid. Temperature of 10 wt% weight loss under nitrogen and air atmosphere is 17°C and 39°C higher than those of m-aramid. Besides, the thermal degradation behavior of h-aramid was studied, and its degradation process and mechanism was proposed. [ABSTRACT FROM AUTHOR]

Magnetic Fe2O3 nanopowder was synthesized and characterized by various analytical techniques. The PVA/Fe2O3 nanocomposites were prepared by solution casting method to investigate the effect of nanofillers on their physicochemical properties. The analytical tools such as FTIR, UV–visible spectra and XRD were used to analyze the structure of Fe2O3 nanopowder and PVA/Fe2O3 nanocomposites. The uniform distribution of the Fe2O3 nanofillers on the PVA matrix was inspected using SEM. The particle size of the crystalline Fe2O3 nanofillers was observed to be less than 30 nm from the TEM micrographs. The optical characteristics of the prepared samples were investigated by analyzing their UV–visible spectra. The bandgap of PVA nanocomposites was lower than for pure PVA due to the dispersed Fe2O3 nanofillers in the PVA matrix. The thermal properties of pristine PVA and PVA/Fe2O3 nanocomposites were investigated by TGA. The PVA/Fe2O3 nanocomposite systems exhibited the improved thermal stability. The thermal degradation mechanism of PVA/Fe2O3 nanocomposite system was inspected in depth at five different heating rates under non-isothermal conditions. The electrical and mechanical properties of PVA were enhanced remarkably while increasing the % weight loading of nanopowder. [ABSTRACT FROM AUTHOR]

The thermal stability of 4-(1-adamantyl)phenol has been studied in the temperature range of 703–753 K, the components of the thermolysis reaction mixture have been identified, and the rate constants and parameters of the Arrhenius equation for the thermal degradation of the compound under study have been calculated. It has been found that of the thermal stability of 4-(1-adamantyl)phenol significantly surpasses that of 4-tert-butylphenol. [ABSTRACT FROM AUTHOR]

Filling a polymer with halloysite nanotubes is considered a promising strategy to generate nanocomposites with tailored physicochemical properties. We have focused our attention on pluronic block copolymer/halloysite nanocomposites prepared by melt blending. The effect of composition on thermal stability and polymer crystallinity was investigated by thermogravimetry and differential scanning calorimetry. Electron microscopy was used to monitor the nanoparticle distribution in the polymeric matrix. The pluronic thermal stability is reduced by the clay nanoparticles. Concerning the polymer crystallinity, it is slightly decreased even if the melting temperature is lowered by halloysite. Furthermore, waterlogged archeological wood samples are consolidated using the nanotubes/pluronic nanocomposite, and the penetration of the nanocomposites into the lignin channels is confirmed by measurements based on X-ray computed microtomography. [ABSTRACT FROM AUTHOR]

Hydrochloric acid hydrolysis in its gas form was used to produce cellulose nanoparticles from flax shives with a very high yield (> 90%). The efficiency of the transformation was examined by gravimetry, atomic force microscopy and transmission electron microscopy. A novel purpose-built anisotropic line-broadening X-ray diffraction model was used. This XRD method uses a parametric shape in order to address the issue of strongly broadened and overlapping Bragg rays that are characteristic of nano-sized crystallites. This method demonstrated the remarkable stability of the crystallite shapes during hydrolysis and its sensibility was sufficient to detect a minor co-crystallization along the hydrophilic faces. The presence of amorphous material strictosensu in the form of individual and randomly oriented chains was not necessary to describe the diffractograms accurately. Thermal FTIR with isotopic exchange was also performed using deuterium oxide to characterize the accessibility of the materials between 20 and 260 °C. Further, back-exchange experiments were performed in order to quantify the hysteretic amount of deuterium that was trapped by microstructural reorganization. These experiments showed that hydrolysis cancelled any form of deuterium trapping (water-induced co-crystallization). For the first time, thermal FTIR demonstrated that isotopic labelling of cellulose sources can produce false positives when conducted at room temperature and thermal FTIR can unambiguously distinguish between labelled cellulose groups and free deuterium oxide, which is paramount when measuring the higher accessibility of the nanocelluloses. It was also demonstrated that the high-temperature hydrogen bond reorganization and thermal degradation of the cellulose chains strongly depend on the hydrolysis and on the microstructure of the substrate. [ABSTRACT FROM AUTHOR]

Improving the stability of all‐inorganic halide perovskite nanocrystals has become an urgent task that cannot be ignored in practical applications. Lead halide perovskite CsPbX3 (X = Br, I, Cl) compounds are considered as the potential materials for next‐generation light‐emitting devices due to their superior optical properties. However, they are threatened by thermal degradation and atmospheric moisture. In order to better solve this practical problem, CsPbBr3 quantum dots (QDs) and CsPbBr3@Cs4PbBr6 nanocrystals (NCs) are tested under heating and cooling cycles, and the photoluminescence (PL) intensity loss of different perovskite materials at high temperatures is investigated. In addition, a thermoplastic polyurethane encapsulation strategy is proposed to improve their properties of thermal degradation and moisture resistance. This inexpensive and convenient method not only greatly reduces the PL intensity loss, but also shows excellent PL performance even in water. The encapsulated material has both flexible and elastic properties, which paves the way for the next commercial processing of all inorganic perovskite materials. [ABSTRACT FROM AUTHOR]