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The preparation and characterization of composite materials composed of polypropylene (PP) as the base mixed with halloysite nanotubes (HNT) at various weight percentages (0.5, 1.5, and 3 wt.%) using a melt extrusion method operated at a temperature between 190 °C and 200 °C is described. The impact of the addition of the HNT filler on the PP nanocomposites was investigated based on the thermal and mechanical properties. The thermal characterization was conducted by differential scanning calorimetry (DSC). Significant increases in the rheological properties were observed with the addition of a high content of HNTs. The water absorption decreased with increasing HNT. The SEM micrographs showed that the HNT fillers were homogeneously dispersed throughout the entire PP matrix. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The objective of this work was to investigate the influence of selected drying temperatures (50, 60, and 70 °C) and ethanol treatment (ET) on the degradation of carotenoids (storage at 35 °C for 35 days), thermal features (TGA and DSC; thermogravimetric and differential scanning calorimetry analysis), and zeta potential of avocado pulp powder produced by foam-mat drying (FMD). Results showed the goodness-of-fitting between the zero and first-order models (R2 > 0.99) for carotenoids degradation kinetics, and further, the ET combined with increasing drying temperatures improved the stabilization of carotenoids during storage. The GAB model presented the best adjustment to the water adsorption isotherms (R2 > 0.99, P < 5%), being classified as type III. Great thermal stability was highlighted by both TGA and DSC curves, pointing out that the main endothermic events were linked to the carbonization of the organic content and degradation of proteins, lipids, and polysaccharides of the powder. In addition, the synergistic effect between drying temperature and ET enhanced the initial, peak, and conclusion temperature and reduced the enthalpy variation. Zeta potential analysis confirmed the stability of FMD-produced avocado powder due to the negative charges ranging from − 29.756 to − 26.826 mV. Overall, these results bring innovative and creative end-uses for avocado in the food industry, establishing FMD as a simple, efficient, and creative process to convert food matrices such as avocado into stable powders. [ABSTRACT FROM AUTHOR]

2,6-Di-tert-butyl-4-methylphenol (BHT) is an excellent antioxidant that is easily oxidized to 2,6-di-tert-butyl-4-hydroperoxyl-4-methyl-2,5-cyclohexadienone (BHTOOH). For the safety of BHT production and usage, it is meaningful to study the thermal stability and decomposition properties of BHT and BHTOOH. In this paper, the thermal decomposition properties of BHT and BHTOOH were compared by the mini closed pressure vessel test (MCPVT) and differential scanning calorimetry (DSC). Their kinetics of thermal decomposition were studied using thermogravimetric analysis (TGA). The thermal decomposition products of BHT and BHTOOH were analyzed by gas chromatography-mass spectrometry (GC–MS). The results show that there was no significant change in temperature pressure when BHT was warmed up under a nitrogen atmosphere, indicating that BHT was stable within 400 K. The thermal decomposition reaction of BHTOOH was rapid with an initial reaction temperature of 375.2 K. The initial exothermic temperature (Ti) and heat release (QDSC) of DSC were 384.9 K and 865.0 J g−1, respectively. The apparent activation energies (Ea) for the thermal decomposition reactions of BHT and BHTOOH calculated by the Kissinger method were 151.8 kJ mol−1 and 66.07 kJ mol−1, respectively. The main decomposition products of BHT were isobutene and 2-tert-butyl-4-methylphenol. The thermal decomposition products of BHTOOH included BHT, 2,6-di-tert-butyl-4-ethylphenol, 3,5-di-tert-butyl-4-hydroxybenzaldehyde, 4,4′-(1,2-ethanediyl) bis [2,6-bis (1,1-dimethylethyl) phenol, etc. Based on the thermal decomposition behavior and products, the reaction pathway has been described. These results indicate that BHT is a potential thermal hazard during production, storage and application. For the safety of the chemical industry, the oxidation of BHT should be avoided. [ABSTRACT FROM AUTHOR]

Agglomeration is a technological process that is widely applied to obtain powdered products with the appropriate shape and particle size and different physical characteristics and stabilities. The purpose of this research was to study the influences of the composition and storage of powdered infant formulas on their thermal behaviours, as analysed by differential scanning calorimetry (DSC); fatty acid compositions, as determined by gas chromatography; and water activity and water content. This study investigated the influence of the storage time (six months) at temperatures of 20–22 °C and air humidities of 42–45% on powder mixtures and agglomerates. The isotherms of the agglomerates presented a shape and course similar to those of the isotherms of the mixtures from which they were obtained. The agglomeration process affected the stability of the fatty acids in the stored powdered infant formulas. The composition of the fatty acids changed during the storage process. The thermal properties of the powdered infant formulas were not significantly influenced by agglomeration. The compositions of the mixtures and agglomerates influenced the shape and course of the DSC diagrams. Using the DSC method, it was determined whether the fat was a natural component of the powder or it was added in the form of fatty acid preparations. Differences were observed between the shape and course of the DSC curves (heating and cooling) obtained for fresh and 6-month-stored mixtures and agglomerates. [ABSTRACT FROM AUTHOR]

Benzoxazine resin shows great potential as matrix for high performance composites, possessing good processabilty, dielectric property, mechanical property, and thermal properties, but its further application is limited by low crosslinking density and poor curing activity, especially for mono‐cyclic benzoxazines. In this work, melamine, a tertiary amine with a stable triazine structure, was introduced into the aldehyde‐containing mono‐cyclic benzoxazine, in order to achieve higher crosslinking density, higher curing activity, and better thermal properties. The chemical structure of prepolymers was verified by Fourier transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance (1H NMR) spectra, the curing behavior was investigated by differential scanning calorimetry, the thermal properties of polymers were studied by thermogravimetric analysis (TGA) and thermal mechanical analysis (TMA). It was found that the introduction of trifunctional melamine (MA) could lower curing temperature and promote the curing degree. Additionally, a proper amount of MA could increase the crosslinking density and thermal properties of the resultant polybenzoxazine. For example, poly(BZ‐3MA) showed the highest thermal stability with the temperature at 5% weight loss (Td5) of 415°C, carbon residue (Yc) of 67.7%, 23°C, and 2.9% higher than those of poly(BZ). Moreover, the glass transition temperature of poly(BZ‐5MA) reached 204.06°C, 36.51°C higher than that of poly(BZ). [ABSTRACT FROM AUTHOR]

The polydimethylsiloxane/nano-graphite (PDMS-NG) nanocomposites were prepared via a two rolled mixing mill and subjected to characterization using techniques such as Transmission Electron Microscopy (TEM), stress-strain analysis during elongation, as well as thermal properties including Thermo-Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The transition temperature was observed to be below -70°C for PDMS nanocomposites reinforced with Nano-Graphite (NG). The thermogram from the thermo-gravimetric analysis indicated that at 10%, 20%, 30%, and 50% weight loss, the temperatures for PDMS nanocomposites were higher compared to unfilled PDMS. These findings suggest a substantial improvement in the thermal stability of PDMS-NG nanocomposites. [ABSTRACT FROM AUTHOR]

In this study thermal and structural properties characterization were performed for prepared ultra-high molecular weight polyethylene/carbon nanotube (UHMWPE/CNT) nanocomposite sheets by using a melt compounding method. The sheets were prepared by using six types of CNTs; pristine single walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs), oxidized- SWCNT and MWCNT, and amide- SWCNT and MWCNT. Thermogravimetric analysis results revealed that the addition of CNTs increased the nanocomposites thermal stability (17 °C) being produced by P-MWCNT. Differential scanning calorimetry and x-ray diffraction (XRD) results show no significant crystalline structure changes compared with the pure polymer, and increase in crystallinity (4%) for O-SWCNTs additions (4%). Scanning electron microscope images showed improved bridging in the polymer matrix by using oxidized and functionalized CNTs compared with pristine CNTs. These findings suggest that the durability of UHMWPE is enhanced by this nano-modification method, improving its suitability for many lightweight, high strength material applications. [ABSTRACT FROM AUTHOR]

Simple Summary: Bacteriophage endolysins are specialized enzymes that act like natural antibiotics, breaking down the outer layer of harmful bacteria. One specific endolysin, PlyC, has shown promising abilities in effectively combating streptococcal bacteria. However, before considering PlyC as a long-term treatment option, we must comprehend its behavior under various conditions. This study investigated PlyC's stability under different temperatures to assess its potential as a therapeutic option. The findings revealed that when exposed to 46 °C, PlyC's structure starts to unfold, rendering it inactive. Particularly, the PlyCA region containing two enzymatic domains is highly sensitive to temperature changes, leading to PlyC's overall inactivity. In contrast, PlyCB, the part responsible for binding to bacterial surfaces, can endure higher temperatures: up to about 75 °C. Understanding the behavior of PlyC, along with its PlyCA and PlyCB domains, is crucial for its future development as a highly effective treatment against bacterial infections. Bacteriophage endolysins degrade the bacterial peptidoglycan and are considered enzymatic alternatives to small-molecule antibiotics. In particular, the multimeric streptococcal endolysin PlyC has appealing antibacterial properties. However, a comprehensive thermal analysis of PlyC is lacking, which is necessary for evaluating its long-term stability and downstream therapeutic potential. Biochemical and kinetic-based methods were used in combination with differential scanning calorimetry to investigate the structural, kinetic, and thermodynamic stability of PlyC and its various subunits and domains. The PlyC holoenzyme structure is irreversibly compromised due to partial unfolding and aggregation at 46 °C. Unfolding of the catalytic subunit, PlyCA, instigates this event, resulting in the kinetic inactivation of the endolysin. In contrast to PlyCA, the PlyCB octamer (the cell wall-binding domain) is thermostable, denaturing at ~75 °C. The isolation of PlyCA or PlyCB alone altered their thermal properties. Contrary to the holoenzyme, PlyCA alone unfolds uncooperatively and is thermodynamically destabilized, whereas the PlyCB octamer reversibly dissociates into monomers and forms an intermediate state at 74 °C in phosphate-buffered saline with each subunit subsequently denaturing at 92 °C. Adding folded PlyCA to an intermediate state PlyCB, followed by cooling, allowed for in vitro reconstitution of the active holoenzyme. [ABSTRACT FROM AUTHOR]

This study aimed to production, optimization, and characterization of an exopolysaccharide (EPS) by Bacillus coagulans IBRC-M10807. The maximum EPS production (234.21 ± 4.83 mg/L) was obtained under optimal incubation temperature 54.95 °C, incubation time 31.36 h, initial pH 5.73, casein peptone concentration 3.93%, and lactose concentration 1.33%. The monosaccharide compositions of EPS were mannose, rhamnose, glucose, and galactose, with an average molecular weight of 4.22 × 105 Da. Differential scanning calorimetry and thermogravimetric analysis showed that the EPS had high thermal stability with a melting point of 262.5 °C and degradation temperature of 276.29 °C. DPPH radical scavenging, hydroxyl radical scavenging, and reducing power of EPS were 85.25% ± 0.55%, 80.08% ± 0.31%, and 0.824 ± 0.008 at 2 mg/mL concentration, respectively. These results indicated that the EPS produced by B. coagulans IBRC-M10807 could be a promising candidate for use as a safe and natural antioxidant as well as a functional ingredient in the pharmacy and food industry. [ABSTRACT FROM AUTHOR]

In this work, we studied, the vibrational and the thermal properties of the Tl2O–TeO2, V2O5–TeO2 and Tl2O–V2O5–TeO2 glass-forming systems by means of Fourier Transform Infrared (FTIR) spectroscopy and Differential Scanning Calorimetry (DSC). Thermal properties, such as the glass transition temperature (Tg), thermal stability (S), and thermodynamic fragility (F), were determined and correlated with the structural characteristics of the glasses. The binary glass-forming system Tl2O–TeO2 exhibits the transformation of TeO4 trigonal bipyramids into TeO3 trigonal pyramid units due to the presence of Tl2O. The decreasing trend of Tg with Tl2O content, along with the increase of the thermodynamic fragility, indicates that the structure becomes less interconnected and floppier. Concerning the V2O5–TeO2 glass system, we observed that V2O5 causes structural modifications in the TeO2 sub-network by changing the coordination number of Te atoms. Furthermore, the glass rigidity reduces as indicated by the glass transition temperature variation with composition. We also found that the 0.5V2O5–0.5TeO2 glass exhibits the highest resistance to thermal shocks and possesses the most rigid network. Concerning the structure of the ternary glass-forming Tl2O–TeO2–V2O5 system, the incorporation of Tl2O into the mixed vanadate–tellurite glasses decreases the glass transition temperature implying that Tl2O acts as a network modifier affecting the network's rigidity. The decreasing trend of the thermodynamic fragility indicates that the glass network becomes more rigid. Finally, the significantly high values of thermal stability reveal that the ternary glass-forming system can be considered as a glass with superior resistance against thermal shocks making it an ideal candidate for relevant technological applications. [ABSTRACT FROM AUTHOR]

Novel phosphorus- and spiro phosphorus-based maleimides such as tris[4-(2,5-dioxopyrrol-1-yl)phenyl] phosphite (TDPPI), tris[4-(2,5-dioxopyrrol-1-yl)phenyl] phosphate (TDPPA), 3,9-di[4-(2,5-dioxopyrrol-1-yl)phenoxy]-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane (TDU), and 3,9-di[4-(2,5-dioxopyrrol-1-yl)phenoxy]-2,4,8,10-tetraoxa-3λ5,9λ5-diphosphaspiro[5.5]undecane 3,9-dioxide (TDUD) have been synthesized. The structural characterization of the synthesized maleimides was performed using elemental analysis, Fourier transform infrared (FTIR) spectroscopy, and 1H, 13C and 31P nuclear magnetic resonance spectral data. Melting behavior and heat changes during the materials' physical and chemical changes as a temperature function were studied using differential scanning calorimetry (DSC). Mass loss rate, residual mass and the gases evolved during thermal degradation were examined using a thermogravimetric (TG) analyzer coupled with FTIR. All four maleimides having a low enthalpy of curing and high char residue (about 50 wt%) display better thermal stability than the parent N-(4-hydroxy phenyl)maleimide (N4HPMI). This was owing to the presence of phosphorus or spiro phosphorus moiety in conjunction with the maleimide unit. The combined impact of phosphorus and maleimide units makes the materials suitable for high-performance applications. [ABSTRACT FROM AUTHOR]

In this research work, we aim to study the effect of the incorporation of vegetable fiber reinforcement on the thermo-mechanical and dynamic properties of a composite formed by a polymeric matrix reinforced with cellulosic fibers with the various Washingtonia fiber (WF) loadings (0%, 10%, 20%, and 30% by wt%) as reinforced material in high-density polyethylene (HDPE) Biocomposites to evaluate the optimum fiber loading of biocomposites. In addition, several characterization techniques (i.e., thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermal mechanical analysis (TMA)) were used to better understand the characteristics of the new composites prepared. With these techniques, we managed to verify the rigidity and thermal stability of the composites so elaborated, as well as the success of the polymer and the structural homogeneity of the obtained biocomposites. Hence, the biocomposite with the best ratio (HDPE/20WF) showed a loss modulus (E″) of 224 MPa, a storage modulus (E′) of 2079 MPa, and a damping factor (Tanδ) of 0.270 to the glass transition (Tg) of 145 °C. In addition, thermomechanical analysis (TMA) of the biocomposite samples exhibited marginally higher Ts compared to the HDPE matrix. The best results were recorded with biocomposites with 20% WF, which showed better thermal properties. This composite material can be used as insulation in construction materials (buildings, false ceilings, walls, etc.). [ABSTRACT FROM AUTHOR]

Polymer nanocomposites based on PP/Cu were obtained by the combining of ex-situ casting solution and hot pressing methods. The structure of polymer nanocomposites was characterized by XRD, SEM, EDS, AFM and FT-IR spectroscopy analysis. The thermal properties were analyzed using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It was found that the addition of copper nanoparticles to the PP polymer matrix increases the thermal stability of the polymer, and this thermal stability reaches its maximum value at 3% content of copper nanoparticles in the polymer. The reason for the increase in the thermal properties of nanocomposites is associated with the formation of a more perfect, dense and ordered structure of PP-based composites and the fact that nanoparticles play the role of a nucleus of crystallization for polymer matrices. [ABSTRACT FROM AUTHOR]

Glazes of (70 − x) ZnO-30 B2O3-x Bi2O3 with different Bi2O3 contents were prepared by the conventional melt quench technique. Differential scanning calorimetry (DSC) curves were obtained to determine the glass transition temperature (Tg) and crystallization temperature (Tc) of the glazes. The activation energy of the glass transition (Eg) and crystallization (Ec) were calculated using the Moynihan and Kissinger models, respectively. The glass transition temperature (Tg) decreased linearly with increasing Bi2O3 content. This is because the larger Bi3+ ions reduced network connectivity and opened up the structure. The Tg increased gradually with increasing heating rate (β). This is because the higher heating rate provided more energy for the glass to transition to the liquid state. The activation energy of the glass transition (Eg) decreased with increasing Bi2O3 content. This indicates that the glass-forming ability of the system increased with increasing Bi2O3 content. The energy corresponding to the amorphous-to-crystalline transformation during nucleation and crystal growth (Ec) increased with increasing Bi content to about 30%, and then decreased above 40%. This suggests that higher Ec values have an advantage in preventing crystallization in the crystallization danger region. It can be seen that the addition of Bi2O3 in (70 − x) ZnO-30 B2O3-x Bi2O3 glazes affects the density and distribution of oxygen atoms in the glass structure. It can also be seen that the increased Bi content promotes the formation of Bi-O-Bi bonds, which act as network modifiers to reduce the number of non-cross-linked oxygen atoms and increase network connectivity. [ABSTRACT FROM AUTHOR]

The experimental studies on the thermal properties and decomposition course of a novel class of potential anticancer drugs (1–5) containing in their heterobicyclic structures the asymmetrical triazine template were performed with the use of differential scanning calorimetry (DSC) and simultaneous thermogravimetry/differential scanning calorimetry (TG/DTG/DSC) coupled online with Fourier transform infrared spectroscopy (FTIR) and quadrupole mass spectrometry (QMS) in inert and oxidizing conditions. All the compounds were thermally characterized in detail for the first time in this article. The DSC studies proved that the melting points of the tested compounds depended on the position and type of the substituent at the phenyl moiety, whereas they did not depend on the furnace atmosphere. All the tested polynitrogenated heterocycles proved to be molecules with high thermal stability in both atmospheres, and most of them (1, 3–5) were more stable in oxidizing conditions, which indicated the formation of a more thermally stable form of the compounds when interacting with oxygen. The simultaneous TG/FTIR/QMS analyses confirmed that their pyrolysis process occurred in one main stage resulting in the emission of volatiles such as NH3, HNCO, HCN, CO, CO2, H2O, NO2, aromatic amine derivatives, alkenes (for compounds 1–5), and HCl (for the compound 5). On the other hand, the oxidative decomposition process was more complicated and proceeded in two main stages leading to the emission of NH3, CO2, CO, HCN, HNCO, H2O, some aromatics (for compounds 1–5), HCl (for compounds 3–5) as well as the additional volatiles such as N2, NO2, NH2OH, and (CN)2. The type of the formed volatiles indicated that the decomposition process of the studied heterocycles under the influence of heating was initiated by the radical mechanism. Their decomposition was related to the symmetric cleavage of C–N and C–C bonds (inert conditions) and additional reaction of the volatiles and residues with oxygen (oxidizing conditions). [ABSTRACT FROM AUTHOR]

In this paper, 1,2,4-triazolium 2,4,5-trinitroimidazolate (2), 3-amino-1,2,4-triazolium 2,4,5-trinitroimidazolate (3) and 4-amino-1,2,4-triazolium 2,4,5-trinitroimidazolate (4) were synthesized based on the method of acid-base neutralization and precipitation, which is a simple method compared with the method in Gao's literature. These compounds were characterized by FT-IR, NMR, elemental analysis. The structure of (2) was further confirmed by single-crystal X-ray diffraction. Thermal decomposition performances of (2)-(4) were tested using differential scanning calorimetry (DSC) and accelerating rate calorimeter (ARC). The DSC curves of (2)-(4) show that they all have good thermal stability and the order of thermal stability is (4) > (2) > (3). ARC test data calculation results show that the thermal stability of (2)-(4) is (3) > (2) > (4). The test results show that the thermal stability of compounds (2)-(4) under non-adiabatic and adiabatic conditions was quite different. The storage temperature of (2), (3) and (4) does not exceed 420.93 K, 435.78 K, and 393.69 K, respectively, and they will not undergo self-accelerating decomposition. [ABSTRACT FROM AUTHOR]

In this present work, the influence of different clays on the thermal and combustion properties of reed flour (RF) reinforced polyvinyl chloride (PVC) composites were investigated. Firstly, two types of nanoclay, namely layered double hydroxide (LDH) and halloysite nanotube (HNT) were modified with a surfactant before usage. Thereafter, the weight loss, melting temperature, and fire characteristics were evaluated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and cone calorimeter tests. The result revealed the addition of both mLDH and mHNT clays can distinctly enhance the thermal stability of the composites by increasing the decomposition temperature and char residues. The samples including mHNT (32.23%) showed higher residual weight values compared to those of the samples with mLDH (29.82%). DSC data indicated that both the crystallization temperature and melting temperature of the specimens tended to substantially increase in presence of nanoclay. The findings showed that the heat release rate and mass loss rate of the specimens treated with mHNT are respectively reduced by 2.1%, and 7.8% compared to that of mLDH. Both time to ignition and limiting oxygen index values increased approximately 9% as the 5 phc mHNT was incorporated into the specimens as compared with mLDH ones. [ABSTRACT FROM AUTHOR]

This paper presents a study conducted on prepregs manufactured by a novel method for the impregnation of a thermoplastic matrix. Different composite prepregs based on polypropylene and reinforced with natural fibers (e.g., basalt and jute fibers) were developed. The mechanical and dynamic mechanical properties were investigated. DMA tests were conducted at 1 Hz frequency and properties such as storage modulus and damping (tan δ) were evaluated. The overall mechanical properties of the basalt fiber composites were found to be superior to that of the jute fiber-based samples. Thermo-gravimetric analysis (TG/DTG) of the composite samples showed that the thermal degradation temperatures of the basalt-based composites shifted to higher temperature regions compared to the PP or jute fiber composites. The addition of basalt fiber considerably improved the thermal stability of the composite samples. Microscopic images of the tensile fractured composite samples illustrated better fiber–matrix interfacial interaction due to the novel technology of prepregs. Single-ply and 2-ply prepregs showed significantly superior mechanical, thermal, and thermo-dynamical performance compared to the control sample (pure PP). 2-Ply composites demonstrated higher modulus, tensile strength, and storage modulus due to the higher fiber volume fraction. Basalt-based samples showed a minimum weight loss of about 57% up to 700 °C in contrast to 96.05% weight loss in the jute-based samples and 98.4% in the case of pure PP. The heat resistance index (THRI) is more than twice for basalt compared to jute and PP. Furthermore, the superior thermal stability of basalt is reflected in its DSC curves, showing the highest endothermic peak. The technique of using the resin in the form of thermoplastic yarns offers cost effective and efficient alternatives for composite manufacturing. [ABSTRACT FROM AUTHOR]

Few‐layer molybdenum disulfide (MoS2) was prepared by liquid phase exfoliation with in‐situ modification as a nanofiller for polypropylene (PP). Scanning and transmission electron microscopies (SEM, TEM) showed uniform dispersion and excellent adhesion of MoS2 within the PP matrix. When MoS2 was centrifuged at 1000 rpm, the mechanical properties of the composite were greatly improved by adding only 0.5 wt.% of MoS2. The yield strength, bending modulus, and impact strength increased by 2.3%, 8.9%, and 44.03%, respectively. X‐ray diffraction (XRD) and differential scanning calorimetry (DSC) showed that the enhanced mechanical properties of the composites were related to PP crystallographic transformation. Thermogravimetric analysis (TGA) showed that the incorporation of 2 wt.% MoS2 increased the maximum weight‐loss temperature of the composites by approximately 30°C. The mechanisms for increasing thermal stability have been thoroughly demonstrated by band energy analysis. MoS2 nanosheets have high aspect ratios and strong insulation with a change in band gap width compared to bulk MoS2, which is resulting in the stronger interactions at the MoS2/PP substrate interface. Furthermore, due to the outstanding carrier for rigid and thermally stable materials, MoS2 composites displayed excellent mechanical and thermal properties. In addition, unlike PP, the melt flow rate (MFR) of composite materials is more conducive to downstream product processing. This will further promote the application scope of MoS2/PP composites. [ABSTRACT FROM AUTHOR]

Recently, there has been a great demand for boron‐containing compounds (BCCs) with unique biological properties. The demand for the use of these compounds not alone but as additives in composite materials is increasing day by day. In this study, the effect of adding B2O3 compound to the blend of PLA and PEG polymers, which is an important biocompatible shape memory polymer, was investigated. In order to examine the effect of increasing B2O3 additive on the thermal properties of PLA‐PEG blend, it was determined by using a Differential Scanning Calorimetry (DSC) and thermogravimetric analyzer (TGA), and it was seen that while the melting temperature of PEG decreased, the melting temperature of PLA increased. In addition, when the thermal stability of the composites was examined, increasing of thermal stability was observed with the addition of B2O3 and a three‐step degradation occurred. It was determined that the B2O3/PLA‐PEG composite was homogeneous by taking X‐ray measurements and SEM measurements. The antimicrobial property of the PLA‐PEG blend improved with the increasing B2O3 contribution were observed from the antimicrobial activity measurements of the composite against 4 different bacteria. However, it was determined that the PLA‐PEG blend preserved its shape memory effect with increasing diboron trioxide contribution. [ABSTRACT FROM AUTHOR]

Using Kraft lignin, bio-based adhesives have been increasingly studied to replace those petrochemical-based solutions, due to low cost, easy availability and the potential for biodegradability of this biomaterial. In this study, lignin-based phenol-formaldehyde (LPF) resins were synthesized using commercial Eucalypt Kraft Lignin (EKL), purified at 95%, as a phenol substitute in different proportions of 10%, 20%, 30% and 50%. The properties of bio-based phenol formaldehyde (BPF) synthesized resin were compared with phenol-formaldehyde resin (PF) used for control sampling. The results indicated that viscosity, gel time and solid contents increased with the addition of pure EKL. The shear strength test of glue line was studied according to American Society for Testing and Materials (ASTM), and BPF-based results were superior to samples bonded with the PF as a control sample, being suitable for structural purposes. Changes in the curing behavior of different resins were analyzed by Differential Scanning Calorimetry (DSC), and sample comparison indicated that the curing of the LPF resin occurred at lower temperatures than the PF. The addition of EKL in PF reduced its thermal stability compared to traditional resin formulation, resulting in a lower decomposition temperature and a smaller amount of carbonaceous residues. [ABSTRACT FROM AUTHOR]

The use of biowaste materials as additives in polymeric matrices has generated interest. Garlic is a seed that has wide application areas, not only in the food industry, because it has good bactericidal and antioxidant properties. Polypropylene (PP) is a commodity polymer that has a wide range of applications, including containers, construction materials, automotive parts, domestic issues, etc. In the present work, the obtaining of composite materials based on a Polypropylene with a medium melt flow index as a matrix and as a reinforcing agent garlic husk particles (GHP). The addition of GHP in different contents was evaluated (2 to 10 PHR), and the composites were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and X-ray diffraction (×RD). According to the results, the thermal stability of PP-GHP decreases with the GHP, in addition to the results of DSC and XRD, that showed that the crystallinity of PP-GHP composites was higher compared to the pristine PP. DMA results allow us to identify that the addition of GHP generates a reinforcing effect on PP matrix, which means that this waste material can be considered a bioadditive with positive effects on polymeric matrices. [ABSTRACT FROM AUTHOR]

The goal of this research is to see how the amount and particle size of calcium carbonate (CaCO3 ) used in the foamed layer in use for PVC-coated textiles affects the thermal properties of the material. Two different particle sizes were used at various concentrations. The impact of different CaCO3 loadings and particle sizes on the PVC foamed layer’s thermal properties were examined. Thermogravimetry (TGA and DTG) and differential scanning calorimetry (DSC) measurements were utilized to investigate the thermal properties of the PVC foamed layer and the samples have been also characterized by FTIR spectroscopy. According to the findings, the thermal stability of the foamed layer was improved with the addition of calcium carbonate. Through the higher surface area between the filler and the PVC matrix, smaller particle sizes have produced the best results. The PVC foamed layer shows also changes in FTIR spectra after adding CaCO3, and the intensity of peaks increases with decreasing CaCO3 particle size. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the aging of poly(ether-ether-ketone) (PEEK) submitted to different media: in air, in water bubbled with nitrogen, in water bubbled with air, and in water at pH 4, for 90 days at temperatures of 120, 140 and 160 °C. The physical, thermal and mechanical properties of PEEK specimens were evaluated before and after aging. The density measurements showed that the aging conditions employed did not promote water absorption or mass loss; thermogravimetric analyses (TGA) showed that all aging media exerted the same effects on the material's thermal stability, with variation in the initial thermal degradation (Tonset) below 5 °C concerning the unaged polymer. The thermal history obtained by differential scanning calorimetry (DSC) did not show significant variations in thermal transition temperatures in the first heating cycle, indicating that the aging conditions did not cause internal degradation in PEEK samples within the studied period. The degree of crystallinity calculated by X-ray diffractometry (XRD) and DSC demonstrated a slight increase over time due to thermal annealing at temperatures above the Tg of the unaged PEEK. The mechanical properties of the aged PEEK showed low variations in Young's modulus and greater variations in the tension at rupture and elongation at rupture, being more drastic in the aqueous media saturated in air and acid solution. [ABSTRACT FROM AUTHOR]

In this study, structural, thermal, mechanical and water uptake properties on the influence of alkaline treated cellulose nanoparticles (CNPs) filled starch-based bioplastic film is examined. Starch-based bioplastic films filled with alkaline treated CNPs at various concentration (0 to 5 wt%) were prepared by solution casting method. Thermal properties of film series are examined by Differential Scanning Calorimetry (DSC) and Thermogravimetry analysis (TGA) method. Alkaline treated CNPs addition induces crystallization to the bioplastic film. Degradation onset temperature (Don), 10% mass loss (T10) and 50% mass loss (T50) values show the positive effect of CNPs addition into the biopolymer matrix with improved thermal stability. Tensile result shows that about 2.5 times increased is observed in 2 wt% CNPs filled bioplastic films. Water uptake result shows that the alkaline treated CNPs starch-based bioplastic film limit the biopolymer dissolution time and extended the breaking down of the bioplastic film. Leading to about 2.5 times reduced equilibrium water mass uptake is observed in 3 wt% CNPs filled bioplastic film when compared with unfilled bioplastic film. [ABSTRACT FROM AUTHOR]

The objective of this study is to investigate chemical, physical, mechanical and thermal properties of novel cellulosic fiber extracted from the bark of Tecoma stans tree. Tests such as chemical, X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis and differential scanning calorimetry were carried on TS fibers. Higher cellulose and lower wax content in TSF make them stronger and establish better interfacial adhesion. X-ray diffraction analysis revealed the crystallinity index and crystallite size of TSF as 31.24% and 2.2 nm respectively. From thermogravimetric analysis, TSF was found to withstand up to 334°C and exhibit activation energy 72.03 kJ/mol. Tensile strength (330-543 MPa) and Young's modulus (9.60-16.28 GPa) of TSF were found to be comparatively higher than other natural fibers. The morphology of TS fiber surface examined through FESEM revealed the existence of cellular structure with some serrations which makes the surface rougher and results in better adherence with polymer matrix. [ABSTRACT FROM AUTHOR]

The environmental threats posed by manmade composites during their disposal and depletion of fossil fuel resources have necessitated the application of ecofriendly materials for composite making. In the recent decades, many plant fibers with promising potentials required for reinforcing composites have been identified and used for various applications. In this paper, physical, mechanical, and thermal properties in addition to chemical composition of novel lignocellulosic fiber extracted from the bark of Albizia saman (AS) have been reported. Chemical tests on ASFs revealed the presence of high cellulose and lignin contents (60.76% and 14.64%), which contributes significantly to the strength and rigidity of the AS fiber. FT-IR and X-ray diffraction study confirmed the presence of cellulose with high degree of crystallinity (57.69%) and crystallite size (2.85 nm). Thermal stability of ASFs studied through Thermogravimetric, Derivative Thermogravimetric, and Differential Scanning Calorimetry curves revealed the maximum degradation of ASFs as 306.19°C with kinetic activation energy (KAE) of 64.01 kJ/mol. The tensile strength and tensile strain of ASFs was found to be to be in the range 381–1092 MPa and 1.65–4.42%, respectively, and the value of tensile modulus was found to be 9.68–42.31 GPa. From the results, it can be concluded that ASFs possess the essential characteristics required for reinforcing composites and hence can be suitably used for making green composites. [ABSTRACT FROM AUTHOR]

Despite a recent sustained preoccupation for developing biobased epoxies with enhanced applicability, such products have not been widely accepted for industry because of their inferior characteristics compared to classic petroleum-based epoxy thermosets. Therefore, significant effort is being made to improve the flame retardance of the most commonly used epoxies, such as diglycidyl ether-based bisphenol A (DGEBA), bisphenol F (DGEBF), novalac epoxy, and others, while continuously avoiding the use of hazardous halogen-containing flame retardants. Herein, a phosphorus-containing bisphenol, bis(4-(((4-hydroxyphenyl)amino)(6-oxido-6H-dibenzo[c,e][1,2]oxaphosphinin-6-yl)methyl)phenyl) phenylphosphonate (BPH), was synthesized by reacting bis(4-formylphenyl)phenylphosphonate with 4-hydroxybenzaldehyde followed by the addition of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) to the resulting azomethine groups. Environmentally friendly epoxy-based polymer thermosets were prepared by using epoxy resin as polymer matrix and a mixture of BPH and 4,4′-diaminodiphenylsulfone (DDS) as hardeners. A hyperbranched phthalocyanine polymer (HPc) and BaTiO3 nanoparticles were incorporated into epoxy resin to improve the characteristics of the final products. The structure and morphology of epoxy thermosets were evaluated by infrared spectroscopy and scanning electron microscopy (SEM), while the flammability characteristics were evaluated by microscale combustion calorimetry. Thermal properties were determined by thermogravimetric analysis and differential scanning calorimetry. The surface morphology of the char residues obtained by pyrolysis was studied by SEM analysis. [ABSTRACT FROM AUTHOR]

• Cotton fibers were modified by silanization and a novel sulphation-phosphorylation approach. • Chemically modified cotton fibers were characterized before and after the surface treatments. • TGA, DSC, and Py/GC–MS analyses were perfomed to characterize the functionalized cotton fibers. • Thermal decomposition and pyrolysis mechanisms and products, were fully studied. The thermal properties and pyrolysis decomposition paths of cotton fibers modified by different chemical treatments, a conventional functionalization with silane and a novel sulphation-phosphorylation approach, were studied. The effects on the fibers thermal behavior and decomposition products were investigated. The cotton fibers were characterized before and after the surface treatments by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and pyrolysis/gas chromatography–mass spectrometry (Py/GC–MS). Morphological investigation was also performed by SEM/EDS analysis to assess the treatment effects on the cotton fibers' surface. The silanization increases the cotton hydrophobicity and thermal stability, changing the pyrolysis mechanism, favoring depolymerization over dehydration and charring. On the contrary, sulphation-phosphorylation methods cause a decrease in the onset temperature and an increase of fire resistance, and charring yield. Thermal decomposition temperatures, weight losses, and pyrolysis mechanisms and products, were fully analyzed. The results can open the way on the use of modified cotton fibers in industrial fields where fireproofing is strongly desired. [ABSTRACT FROM AUTHOR]

In this study, natural fiber-reinforced polylactic acid (NFRP) composite materials were prepared by adding nucleating agents (NAs) and natural fiber (NF) to compensate for the low thermal stability and brittleness of polylactic acid (PLA). The thermal stability of the fabricated composite material was investigated by differential scanning calorimetry and thermogravimetric analysis. In addition, the tensile modulus of elasticity according to the crystallinity of the composite was measured. The crystallinity of the PLA composite increased to ~700% upon the addition of the NA; thus, the thermal stability also increased. However, the changes in crystallinity and tensile modulus were insignificant when the concentration of the NA added was 4 wt.% or higher. The study demonstrates that the addition of NA and NF is effective in improving the thermal stability and mechanical properties of NFRP. [ABSTRACT FROM AUTHOR]

Some disadvantages of commercial dressings have mobilized research groups to clinically improve these materials considering their cost–benefit ratio. Tissue engineering has emerged as a field that uses biomaterials in the form of scaffolds mimicking human morphofunctionality and their combination with cells in order to repair or replace damaged tissues. There is still a need for customization and characterization of the material to ensure its safety. Therefore, this study aimed to perform further characterizations of the gelatin (Gel)–coated poly(ε-caprolactone) (PCL) matrix produced in previous studies by rotary jet spinning. PCL fibers produced by rotary jet spinning were submersed in a Gel solution, inspired by the dip-coating method, followed by crosslinking with glutaraldehyde. The material was then submitted to physicochemical and biological characterization. The thermal properties were confirmed by differential scanning calorimetry. Significant differences were observed in the fiber thickness and swelling of PCL/Gel compared to PCL, while fiber spacing was greater for PCL. The crosslinked Gel appeared to increase the tensile strength of PCL, and the thermal stability of PCL/Gel was higher than that of Gel alone. In addition to the absence of cytotoxicity of the materials, the cytochemical data suggest higher cell activity on the PCL/Gel scaffold. Scanning electron microscopy reinforces this observation, indicating promising applications of PCL/Gel scaffolds in skin tissue engineering. [ABSTRACT FROM AUTHOR]

Two types of polyethylenes, the crosslinked high‐density polyethylene (PEX) and the short‐chain branched medium‐density polyethylene (polyethylene of raised temperature resistance [PE‐RT]), are selected as matrices for graphene nanoplatelets (GNPs) nanocomposites preparation (PEX/GNPs, PE‐RT/GNPs). The melt‐mixing technique is used to synthesize the nanocomposites containing various loadings of GNPs. Differential scanning calorimetry (DSC) is employed to study the effect of the GNPs on the melting and crystallization behavior of the prepared materials. The thermal stability of the nanocomposites was evaluated by thermogravimetric analysis (TGA). Laser flash analysis (LFA) is used to estimate the thermal conductivity of both PEX and PE‐RT/GNPs nanocomposites. TGA measurements reveal that PEX nanocomposites present decreased thermal stability with increasing filler content. The DSC results show that the crystallinity of both matrices increases with increasing filler content. PEX/GNPs nanocomposites show more significant thermal conductivity augmentation compared to the corresponding PE‐RT nanocomposites. [ABSTRACT FROM AUTHOR]

A silicon-containing benzoxazine (PDpsp-a) was synthesized from bis(p -hydroxyphenyl)diphenylsilane, aniline, and paraformaldehyde. The structure of the monomer was supported by 1H-NMR and FTIR spectra. The curing behavior of benzoxazine was evaluated by differential scanning calorimetry and in-situ FTIR spectra. The thermal properties were studied by MDSC, TGA, and Py-GC/MS. The results indicated that the characteristic peak of oxazine ring began to disappear when the temperature was heated to 180°C and completely disappeared at 260°C. The polybenzoxazine (PDpsp-a) possessed a high glass transition temperatures (174°C) and had good thermal stability (T10 = 420°C). In the pyrolysates of polybenzoxazine (PDpsp-a), no silicon-containing compounds, no phenol species, and more benzene were detected, we speculated that the Ar-Si bond would fracture with the increase of temperature. The benzene was volatilized from the system as a pyrolysis product and the silicon could react with oxygen to form siloxanes remained in the carbon residue in the form of siloxane compounds. The formed silica layer could endow the silicon-containing polybenzoxazine high thermal degradation stability and high char yield. [ABSTRACT FROM AUTHOR]

High performance glass fiber reinforced epoxy composites are in greater demand in several industrial applications, from civil structures to aviation industry. The epoxy has highly cross-linked structure and is found to be high performance polymer. Further, carbon nanofillers such as multi-walled carbon nanotubes (MWCNT), graphene nanoplatelets (GNP) and thermally stable microfiller aluminium trihydrate (ATH) are being used to improve the thermal properties. GNP and MWCNT posses high aspect ratio and specific surface area contributing to improvement in thermal properties of composites. In spite of this, there are difficulties connected with nanofiller addition, such as dispersion and interaction. The fabricated nanocomposites are based on ECR glass fiber and epoxy resin by adding GNP, MWCNT and ATH fillers using pultrusion process assisted by ultrasonication. For the purpose of comparison, composites containing only MWCNT, GNP and ATH were also tested. The XRD and SEM were used to study the fillers dispersion and interaction. The thermogravemetric analysis(TGA) was carried out to determine the thermal stability of composites. From the thermal analysis result, it is found that the epoxy-MWCNT-GNP-ATH composite has enhanced thermal stability due to the addition of ATH micro filler. [ABSTRACT FROM AUTHOR]

A new set of cyclopentanone chalcone esters 2,5-bis-(4-alkanoyloxybenzylidene)cyclopentan-1-one (B2-B10) has been synthesized and monitored by TLC. Structures of these compounds were determined by spectroscopic techniques (FTIR, 1H NMR, and mass spectrometry). Differential scanning calorimetry (DSC) and polarized optical microscopy were used to evaluate their transition temperatures and mesophase properties (POM) throughout heating and cooling scans. The thermal data indicate that the compounds B5-B10 have mesomorphic properties with thermal stabilities; the data also reveal that the compounds B6-B10 are monotropic, whereas B5 is enantiotropic. B6, B7, and B9 only have a nematic phase, but B8 and B10 have a smectic phase followed by a nematic phase, and B5 only has a smectic phase. In addition, the study reveals that the inclusion of an acyl group as a terminal chain had the opposite effect on isotropization temperatures for compounds B6, B8, and B10, resulting in an increase in transition temperatures and a decrease in mesophase stability. The lack of a smectic phase in B7 and B9 compounds could be attributed to the narrow phase temperature range, which makes examination difficult, or to the molecules' lack of lateral attraction. [ABSTRACT FROM AUTHOR]

The structure and thermal properties of a new heterometallic complex based on copper and noble metal β-diketonates are described: (hfa = 1,1,1,5,5,5-hexafluoropentane-2,4-dionato, LF = 1,1,1-trifluoro-5-methoxy-5-methyl-hexane-2,4-dionato). According to the single crystal X-ray diffraction data, the synthesized complex represents a 1D coordination polymer completely sublimed at Т = 90 °C and Р = 10–2 Torr, Тmelt = 149 °C. The thermal stability of the complex is analyzed by thermogravimetry and differential scanning calorimetry. The correlation between the thermal stability and the complex and the structural data together with the results of quantum chemical calculations is discussed. The crystal structures, thermal properties, and features of the electronic structure of the Cu–Pt complex and the isoligand Cu–Pd complex are compared for their further use as precursors in the co-deposition of coatings from binary and ternary alloys. [ABSTRACT FROM AUTHOR]

A set of syndiotactic polypropylene/iron (sPP/Fe) composite samples were manufactured with the extrusion technique to study the impact of iron content on the thermal behavior of sPP/Fe composites in the melt phase. The dosage of iron contents varied from 0 to 8%. Melting point (Tm), crystallization temperature (Tc), and thermal degradation temperature (Td) were measured by Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA) for each composite sample. Thermal temperatures (Tm, Tc, and Td) increased with increasing the iron contents due to the enhancement of the strength and thermal stability of the sample. This investigation is a validated fact that fillers (iron) alter both the macroscopic and microscopic properties of the polymer composites. [ABSTRACT FROM AUTHOR]

A biodegradable thermoplastic polymer has been formulated by solubilizing Murexide (M) salts in a commercial biodegradable vinyl alcohol copolymer (HVA). The Murexide has been employed as a self-healing filler with the aim to impart the auto-repair ability to the formulated material. Three different percentages (1, 3, and 5 mass%) of filler have been solubilized in HVA to evaluate the effect of the filler concentration on the thermal and self-healing properties of the resulting polymeric materials. The samples have been thermally characterized by Differential Scanning Calorimetry (DSC) and Thermogravimetric Analyses (TGA), while their self-healing ability has been evaluated through the estimation of the storage modulus recovery, measured by Dynamic Mechanical Analysis (DMA). The results of DSC analysis have highlighted that the increase of the amount of Murexide anticipates the thermal events such as glass transition, crystallization and melting. TGA measurements have evidenced that, although there is a reduction of thermal stability of the materials in the presence of a high concentration of M, the polymer still remains stable up to 270 °C. Healing efficiency higher than 80%, at a temperature beyond 60 °C, has been detected for the samples loaded with 3 and 5 mass% of Murexide, thus confirming the efficacy of this compound as an auto-repair agent and the relationship between the self-healing efficiency and its amount. For a temperature lower than 70 °C, the healing tests, carried out at different values of tensile deformation frequency, have highlighted a frequency-dependent healing efficiency. This dependence becomes negligible at higher temperatures for which the healing efficiency approaches the value of 100%. [ABSTRACT FROM AUTHOR]

Two new MOFs were prepared under solvothermal conditions using 5-aminotetrazole as a ligand with high thermal stability, good detonation properties and low sensitivity, which are potentially safe energetic materials. [Display omitted] • Two new MOFs were prepared under solvothermal conditions using 5-aminotetrazole as the high-nitrogen energetic ligand. • Compound 1 possess an ABX 3 -type perovskite-like structure, whereas compound 2 forms a two-dimensional layer. • Both compounds demonstrated high thermal stabilities, good detonation properties and low sensitivity. Metal-Organic Frameworks (MOFs) have recently gained prominence as a novel class of energetic materials, owing to their systematic design and the ability to fine-tune properties such as energy content, sensitivity, and thermal stability. In this study, two new MOFs namely Cd(5-AT) 3 NH 2 (CH 3) 2 + (1) and Zn(5-AT)(AMP) (2) (5-HAT = 5-aminotetrazole) were prepared under solvothermal conditions using 5-aminotetrazole as the high-nitrogen energetic ligand. X-ray single crystal diffraction analysis revealed that compound 1 possess an ABX 3 -type perovskite-like structure, whereas compound 2 forms a two-dimensional layer. The high thermal stability of both compounds were confirmed through thermogravimetry (TG) and differential scanning calorimetry (DSC). Their constant-volume combustion heat (Δ c U) was first determined by oxygen-bomb calorimetry and then the standard molar enthalpy of formation (Δ f Ho) was calculated. Furthermore, both compounds demonstrated great detonation properties and low sensitivity, showing their potential application as new explosive materials (EMs). [ABSTRACT FROM AUTHOR]

Two types of structurally different benzoxazines (BF-abn and BZ-abn) have been developed using bisphenol-F and bisphenol-Z with 4-aminobenzonitrile and paraformaldehyde through Mannich condensation reaction under an appropriate experimental conditions. Molecular structure of benzoxazine was confirmed by FTIR and 1H-NMR spectral analyses. Cure behavior and thermal stability were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) respectively. The results from DSC analysis indicated that these benzoxazines exhibit marginally lower polymerization temperature than that of conventional benzoxazines. Further, the curing behavior of both benzoxazine samples were studied at two different heating rates viz. 10 °C/min and 20 °C/min to ascertain their heat releasing properties. The formation of polybenzoxazine was confirmed by FTIR analysis after the thermal curing through the cleavage of benzoxazine ring and subsequently led to the formation of three dimensional cross-linked network structure. Results from TGA infers that among the benzoxazines studied, poly(BF-abn) possess better thermal stability than that of poly(BZ-abn). Further, the values of LOI calculated using char yield obtained at 850 °C from TGA for poly(BF-abn) and poly(BZ-abn) are 41% and 30% respectively. The values of water contact angle obtained for poly(BF-abn) and poly(BZ-abn) are 138° and 140° respectively. Both benzoxazine samples exhibit an excellent hydrophobic behavior. [ABSTRACT FROM AUTHOR]

In this century, the development of nano-sized filler from biomass material has become the main focus of industries in achieving their final green composite product for a wide range of applications. From a commercial and environmental point of view, fragmentation and downsizing of waste lignocellulosic fibers without chemical treatments into small size particles is a viable option. In this study, an attempt was made to produce nano-sized lignocellulosic fillers from date palm micro fibers via mechanical ball milling process at intense 99 cycles run (equivalent to 25 h). The resultant nanofillers as well as the microfibers were characterized in details by various analytical techniques, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), particle size analysis (PSA), Energy Dispersive X-Ray (EDX), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) to assess their structure—property relationship. From microscopy examination, the nanofillers showed a heterogeneous mix of irregular shaped particles, and while having a size ranging of 30–110 nm in width and 1–10 mm length dimensions. Also, the crystallography analysis revealed the crystallinity had mildly declined from microfibers (71.8%) to nanofiller (68.9%) due to amorphization effect. As for thermal analysis, the nanofillers exhibited high heat resistance at 260.8 °C decomposition temperature. Furthermore, the nanofillers also had stable thermo-changing behavior by presenting low heat enthalpy change (40.15 J/g) in its endothermic reaction for breaking organic bonds. The thermal results suggest its suitability for composite fabrication process at high temperature. Thus, the produced nanofillers can be used as a low cost reinforcing agent in the future for versatile polymer-based composite systems. [ABSTRACT FROM AUTHOR]

In this study, a kind of novel curing agent composed of acrylic acid and 4,4′‐(hexafluoroisopropylidene)bis(p‐phenyleneoxy)dianiline was mixed, with different contents of diatomite (CP) particles, into the epoxy resin (E51) to obtain bio‐composites that can be rapidly molded and cured at room temperature. Fourier Transform Infrared Spectroscopy and Differential Scanning Calorimetry were used to study the curing behavior of epoxy resin and bio‐composites. The influence of CP particle dosages on the mechanical, including tensile, flexural and impact properties, and thermal properties of the prepared composites were discussed. Thermogravimetric analysis result showed that the thermal stability increased with increasing of CP fillers content. Dielectric property tests confirmed that the dielectric constant of composites decreased attributed to the incorporating of novel curing agent and CP fillers with porous structure into epoxy resin. Finally, Scanning Electron Microscope revealed the excellent adhesion between the cured resin and the fillers. [ABSTRACT FROM AUTHOR]

Tetracyanoquinodimethane (TCNQ) on reaction with primary/secondary amines sequels in mono/di-substituted TCNQ adducts known as diaminodicyanoquinodimethanes (DADQ's) possessing astounding optical or non-linear optical characteristics. Crucially, the subtle choice of amine contributes to the outcome of molecular material aspects. Herein, we present a comprehensive investigation of 7,7-bis(N,N-diethylethylenediamino)-8,8-dicyanoquinodimethane (BDEDDQ); manifesting the impact of ethyl group (existing on the di-substituted nitrogen of N,N-diethylethylenediamine (DEED)); on the crystal structure, optical property and thermal stability. Crystallography study revealed supramolecular self-assemblies among molecular dipoles emanating fluorescence enhancement in the solid state compared to solutions. Quantum yields were primarily ~0.2 to 0.4% in solutions and ~56% in the solid. Stokes shift was noticed to be more in solutions (~90 nm) than solid (~67 nm), suggesting excess vibrational relaxations in solutions. Differential scanning calorimetry revealed ~182 °C as the melting temperature. The heat capacity of solid was found to be 5.03 mJs−1. Thermogravimetric analysis conveyed single stage decomposition process initiated by the two amine side chains. Scanning electron microscopy of films prepared by drop casting solutions imparted divergent morphological features, due to different rates of evaporation accompanied by varied growth kinetics. Accordingly, in this paper we have demonstrated the utilization of simple N,N-diethylethylenediamine (DEED) to successfully generate a noteworthy blue emissive molecular material exhibiting semiconducting feature besides reasonable thermal stability. [ABSTRACT FROM AUTHOR]

This research was targeted to investigate the effect of oxygen plasma treated graphene nanosheets (tGNSs) on the thermal stability of benzoxazine resin and to have a further and deeper mechanistic understanding of thermal decomposition kinetics of such nanocomposites in 0.5, 1 and 3 wt% of tGNS. The samples were prepared as reported in our previous study. The quality of dispersion of tGNSs within benzoxazine was investigated by X-Ray diffraction (XRD) and scanning electron microscopy (SEM) technique. Also, to ensure the complete curing of samples the differential scanning calorimetry (DSC) analysis was performed. Using thermogravimetric analysis (TGA), it was found that the addition of tGNS improved the char yield and thermal stability parameter of benzoxazine nanocomposites and this improvement was more prominent at 1% and higher amount of nanoparticles. Moreover, the first stage of thermal degradation kinetic of benzoxazine was disappeared above 1 wt% of tGNS. The samples were kinetically analyzed through Kissinger, Flynn-Wall-Ozawa and Friedman and Coats-Redfern method. It was revealed that the overall activation energy was enhanced from 168 to 224 kJ mol−1 and 275 to 420 kJ mol−1 for the second and third stage of degradation using 1 and 3 wt% of tGNS. [ABSTRACT FROM AUTHOR]

Native cassava flour can be modified to be instant flour by heating the cassava flour in ethanol solution. The impact of heating temperatures of 60, 80, and 100 °C (coded as ICF-60, ICF-80, and ICF-100) on the properties of instant cassava flour (ICF), including colour, morphological, and thermal properties, water absorption, and solubility indexes and pasting behaviour, were investigated. Results showed that ICF produced at higher temperatures exhibited lower lightness, higher redness, and yellowness values. ICF-60 and ICF-80 still displayed the granular forms and birefringence properties of native starches, while granules of ICF-100 were broken and partially lost their birefringence properties. Results of X-ray diffraction (XRD) technique and differential scanning calorimetry (DSC) analysis suggested that the amylopectin double helixes of crystalline regions within the structure of ICF orientated to more perfect conformation before they were disrupted at the highest heating temperature (100 °C). During hydration, the starch granules of ICF-60 and ICF-80 absorbed water into their granules; meanwhile, ICF-100 entrapped water within the matrix formed by the entanglements of ICF-100 particles. Results of pasting behaviour analysis indicated that ICF-60 and ICF-80 showed better thermal stability while ICF-100 exhibited the highest cold viscosity. [ABSTRACT FROM AUTHOR]

The kinetics of copolymerization is one of the key factors for optimization the process in large scale of production. Copolymerization of N, N‐dimethyl‐N,N‐diallyammonium chloride (DMDAAC) with N,N‐dimethyl acrylamide (DMAA) was studied by a dilatometer technique using ammonium persulfate ([NH4]2S2O8) as an initiator. The effect of the parameters (including molar ratio of DMDAAC to DMAA, concentrations of monomers [M] and initiator [I], and the temperature) on the polymerization rate was analyzed. From these analyses it was found that the polymerization rate (Rp) with the above variables can be represented as the following relationship: Rp∝ [M]2.63; Rp∝ [I]0.40 andRp∝[MDMDAAC:MDMAA]‐0,86.The negative order found in the relationship of the reaction rate and the monomer composition indicated that the DMDAAC concentration in the monomers composition conversely affected the polymerization rate. The overall activation energy for the polymerization rate was 39.56 kJ/mol in the temperature range between 40°C and 60°C. Based on the experimental results, the mechanism of polymerization is discussed in detail. Different thermal properties for DMDAAC and DMDAAC‐DMAA were observed by differential scanning calorimetry (DSC), and thermogravimetry (TG) analysis. Addition of DMAA to DMDAAC lowered the thermal stability relative to the home polymer of DMDAAC. [ABSTRACT FROM AUTHOR]

Porous microspheres obtained from 2,3-epoxypropyl methacrylate (GMA) and 1,4-di(methacryloyloxymethyl) naphthalene (DMN) were modified by the reaction of active oxirane group with 1-(2-hydroxyethyl)-2-pyrrolidone (HP). Spherical shape of the copolymers was confirmed by scanning electron microscopy whereas low-temperature nitrogen adsorption–desorption method was applied to determine their porous structure. It was found that the modification process did not change noticeably the internal structure of the materials. The specific surface area for both types of materials ranged from 41 to 106 m2g−1 depending on the molar ratio of the monomers. Changes, however, were observed in reference to thermal properties. They were studied using differential scanning calorimetry and thermogravimetry coupled with FTIR in inert and oxidative conditions. The reaction with HP reinforced thermal stability of the modified microspheres in helium atmosphere. Their initial decomposition temperatures (IDTs) increased to 273–281 °C. In air atmosphere, the values of IDTs were at the same level (248–269 °C). The modified beads decomposed in three (helium) or two (air) stages. [ABSTRACT FROM AUTHOR]

Crowded environments, commonly found in the food system, are utilized to enhance the properties of soybean proteins. Despite their widespread application, little information exists regarding the impact of crowded environments on the denaturation behaviors of soybean proteins. In this study, we investigated how crowding agents with varying molecular weights, functional groups, and topology affect the denaturation behavior of glycinin under crowded conditions. The results reveal that thermal stability in PEG crowded environments is mainly influenced by both preferential hydration and binding. The stabilization is primarily enthalpy-driven, with aggregation contributing additional entropic stabilization. Specifically, ethylene glycol and diethylene glycol exhibit temperature-dependent, bilateral effects on glycinin stability. At the denaturation temperature, hydrophobic interactions play a predominant role, decreasing glycinin's thermal stability. However, at a molecular weight of 200 g/mol, there is a delicate balance between destabilizing and stabilizing effects, leading to no significant change in thermal stability. With the addition of PEG 400, 1000, and 2000, besides preferential hydration, additional hard-core repulsions between glycinin molecules enhance thermal stability. Methylation modification experiments demonstrated that 2-methoxyethyl ether exerted a more pronounced denaturing effect. Additionally, the cyclization of PEG 1000 decreased its stabilizing effect. [ABSTRACT FROM AUTHOR]