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The study primarily focuses on the in situ synthesis of polystyrene (PS) and copper oxide (CuO) nanocomposites. An extensive analysis was conducted on the optical, thermal, mechanical, and electrical properties of PS with different CuO concentrations. The effective inclusion of CuO into PS was characterized by Fourier-transform infrared spectroscopy (FTIR), UV–visible spectroscopy, filed emission scanning electron microscopy (FE-SEM), X-ray diffractometry (XRD), differential scanning calorimetric analysis (DSC) and thermal gravimetric analysis (TGA). The reinforcement of CuO into the PS was established through FTIR. The optical bandgap energy deduced from UV–visible spectra decreases with CuO addition, whereas the refractive index rises significantly with the addition of CuO nanoparticles up to 7 mass%. The XRD analysis revealed the amorphous to crystalline transformation of PS with the homogeneous dispersion of nanoparticles. The SEM–EDX analysis revealed the uniform distribution of CuO nanofillers in the PS matrix. The CuO addition considerably increased the glass transition temperature and thermal stability of PS. The tensile strength, impact resistance and hardness of nanocomposite were significantly increased with the loading of CuO in the polymer matrix. The AC conductivity and dielectric constant of the PS was improved with the addition of CuO nanoparticles. The effect of temperature on conductivity, activation energy, and pre-exponential factor was determined using the universal power law and the Arrhenius equation. The highest electrical and mechanical properties were observed for 7 mass% nanocomposite. The synthesized PS/CuO nanocomposites with excellent optical characteristics, thermal stability, electrical conductivity, dielectric constant and mechanical strength can be used in supercapacitors and flexible nano-electronic devices. [ABSTRACT FROM AUTHOR]

Composite materials have garnered considerable interest in the thermal industry on account of their remarkable mechanical properties and thermal resistance. The objective of this research work is to analyse the impacts of integrating porcelain infill particles into basalt fibre-reinforced polymer (BFRP) composites. Particularly, the study aims to evaluate the consequential modifications in critical thermal and mechanical characteristics. The results of mechanical testing indicate that the incorporation of porcelain fillings significantly influences the composite tensile strength, flexural strength, and impact resistance. Additionally, by employing scanning electron microscopy (SEM), significant knowledge is acquired regarding the interfacial bonding mechanisms and microstructural properties of the filler particles, polymer matrix, and basalt fibres. Utilizing dynamic mechanical analysis (DMA), the maximal values of storage modulus (3429 MPa), loss modulus (489 MPa), and damping factor (0.17) are investigated in relation to the dynamic mechanical properties across a range of temperature conditions. The research additionally illustrates enhancements in thermal characteristics, including heat deflection temperature, thermal conductivity, and coefficient of linear thermal expansion, all of which are improved by 37% when porcelain infill is incorporated into the composite. In addition, thermal gravimetric analysis (TGA) examines the degradation and thermal stability properties of the composites over an extensive temperature spectrum, reaching a maximum of 390 °C. The insights derived from this analysis are particularly pertinent to applications involving thermal insulation. [ABSTRACT FROM AUTHOR]

The present study aims to investigate the physical, chemical, and thermal properties of chia (CM) and okra (OM) mucilages powders. The mucilages were extracted and dehydrated at 70 °C; then they were evaluated for the profile of total phenolic compounds and mineral profile, colorimetric parameters, morphology by scanning electron microscopy (SEM), infrared by fourier transform (FTIR), X-ray diffraction (XRD), and thermal properties by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA/DTG). It was found that OM had higher amounts of total phenolic compounds, mainly flavonols, with a predominance of quercetin 3-glucoside. On the other hand, CM had the highest content of flavonoids, the most significant being catechin. CM had the highest mineral content, being surpassed by okra mucilage in terms of calcium and copper. The OM had the highest luminosity, with values tending toward yellow and green tones, while the CM was darker and presented yellow and red tones. The mucilages presented morphologically irregular particles with different sizes and shapes, with an amorphous structure. The FTIR showed the bands of the main components, indicating that the mucilages are constituted mainly by polysaccharides (OM), pectins, and soluble proteins (CM). The DSC showed sharp endothermic peaks, indicating greater uniformity and purity of the samples. The thermogravimetric curves and their derivatives showed the greatest mass loss in the second evaluation phase for both materials, followed by the carbonization of organic matter and the formation of fixed mineral residue. The study revealed that mucilages have distinct characteristics, but with excellent properties, which offers great potential as a raw material for industry. [ABSTRACT FROM AUTHOR]

Polyethylene from renewable resources produced using sugarcane as raw material was modified with phosphonium ionic liquids. Tensile properties and thermal behavior of modified biopolyethylene in air and nitrogen atmosphere were studied. The thermal degradation of ionic liquids and their influence on thermal degradation of polyethylene from renewable resources were studied by thermogravimetric analysis (TGA). In general, modification of biopolyethylene with phosphonium ionic liquids resulted in improvement of tensile properties, i.e., tensile strength and Young's modulus. Thermal degradation of biopolyethylene modified with phosphonium ILs proceeds in one step in the range of 400–500 °C in nitrogen atmosphere. Modification of polyethylene with trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl)phosphinate ionic liquid resulted in increase in DTGpeaks and T10% temperatures toward higher temperature for modified polyethylene in comparison with unfilled PE sample both in air and nitrogen atmosphere. [ABSTRACT FROM AUTHOR]

One of the dubious aspects of polymer/clay nanocomposites is its thermal stability compared to the pristine matrix since we can find works indicating different directions with relatively similar materials. This work aims to evaluate the influence of the sepiolite content and the PP-g-MA compatibilizer presence in the polypropylene/sepiolite nanocomposites degradation. PP/Sep nanocomposites were prepared in a twin-screw extruder with 0.75–5 mass% of Sep and with or without 2.5 mass% of PP-g-Ma as a compatibilizer. Material characterizations were performed by X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis (TGA). Morphology showed that the nanocomposites presented some needles agglomeration inside the polymer matrix, indicating the use of compatibilizer PP-g-MA was not enough for dispersion in the nanocomposites produced in this work. TGA results showed different results according to the nature of the atmosphere. In the oxidative atmosphere, the stability of nanocomposites was not significantly influenced by the sepiolite concentration, for concentrations lower than 1 mass%, and slightly influenced by the presence of PP-g-MA as a compatibilizer, while concentrations as large as 5 mass% of sepiolite showed a strong influence on the clay concentration. In the inert atmosphere, we observed the influence of the sepiolite concentration, decreasing the stability of the nanocomposite in the whole range of studied concentration. Regarding the presence of 2.5 mass% of PP-g-MA, all the formulations exhibit almost the same profile of mass loss, evidencing that the compatibilizer prevented the catalytic effect of the sepiolite in the thermal degradation of the nanocomposite. [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]

This work aims to study the influence of torrefaction on the energetic properties and thermal decomposition kinetics of energy cane Saccharum spontaneum. An experimental planning (473–533 K, 15–45 min) was realized, and the best conditions were 503 K and 45 min with mass yield above 70%, which led to the decrease in volatile matter and oxygen contents (15%) and the increase of 14.5% in the heating value. The thermogravimetric analysis (heating rates of 5, 10 and 15 K min−1) under inert atmosphere was used for the application of the independent parallel reactions scheme in the multistep model. The activation energies found were 111, 119, 197 and 51 kJ mol−1 for both raw and torrefied biomasses related to extractive, hemicellulose, cellulose, and lignin, respectively. Then, this approach provided reliable kinetic models capable of describing the thermal decomposition for both raw and torrefied samples (deviation < 3%). [ABSTRACT FROM AUTHOR]

Synthesis of optical materials, copolymers based on methyl methacrylate used as a polymer matrix, and 2,7-bis[2-(2-hydroxy-3-methacryloyloxypropoxy)]naphthalene (2,7-NAF.DM) applied as a photoluminescent dopant are presented. The purification procedure as well as the detailed information about the method of synthesis is shown. Additionally, the effect of varying concentrations of dopant to determine its effect on the course of polymerization process and thermal properties was tested. Possible application of the received materials as optical materials has been studied by the use of the coupled thermal and spectroscopic methods (TG/DTG/QMS). Using these methods, in addition to quantitative information (mass change, process heat), the qualitative information regarding the chemical composition of the gas products is obtained. [ABSTRACT FROM AUTHOR]

This paper presents the thermal properties of highly crosslinked di(methacryloyloxymethyl)naphthalene–divinylbenzene (DMN–DVB) copolymeric microspheres containing polar groups in the structure and their alkyl-bonded derivatives. C8 and C18 alkyl chains were introduced into the aromatic rings of the DMN–DVB porous copolymer by means of the Friedel–Crafts reaction. As a source of C8 and C18 alkyl chains, octyl and octadecyl chlorides were used. It was necessary to check whether the introduction of alkyl chains into the structure of polymeric packing had an impact on its thermal properties. The studies were carried out by thermogravimetry coupled online with FTIR spectroscopy and differential scanning calorimetry in inert atmosphere (helium). It was stated that the modified materials showed 20 and 50% mass losses at higher temperatures than the non-modified one while 1% mass loss was observed at lower temperatures. Moreover, an analysis of volatile decomposition products was performed. [ABSTRACT FROM AUTHOR]

Effect of different chain extenders, silica nanoparticle loading, and using sol-gel method on the thermal properties of polyurethane (PU) hybrid composites was investigated from the viewpoint of increase of char residue and decomposition temperature. Two different chain extenders were used for this purpose, and the PU products were modified with (3-aminopropyl) triethoxysilane to obtain PUI (ethoxysilane-terminated PU with pyromellitic dianhydride chain extender) and PUBD (ethoxysilane-terminated PU with butanediol chain extender), respectively. Fourier-transform infrared spectroscopy was used for confirmation of synthesis of PUI and PUBD. Thermogravimetric analysis showed that char residue and thermal degradation temperature of PU hybrid composites were increased after incorporation of silica nanoparticles. Also, using pyromellitic dianhydride as chain extender resulted in higher char contents and also thermal stabilities in comparison with butanediol. By the addition of 4 and 8 mass% silica nanoparticles in PUBD hybrids, char residue increased to 15.1 and 16.3%, respectively. In the case of PUI hybrids, addition of 4 and 8 mass% of silica nanoparticles resulted in char residue of 20.8 and 25.7% and Tmax of 409.3 and 411.8 °C, respectively. X-ray diffraction showed an amorphous peak for cross-linked PU at 2θ = 21.7°. Transmission electron microscopy showed dispersion of silica nanoparticles in the hybrid composite of PUI. [ABSTRACT FROM AUTHOR]

The functional properties of starch granules define its application in food and non-food industries. Thus, in this study we investigated thermal, rheological, structural and colour properties of the native and modified starch of the Amazon Dioscorea sp. (white yam) tuber. The Dioscorea sp. native starch was modified by applying single, simultaneous and combined modification agents (sodium hypochlorite, ultraviolet (UV) radiation and microwave irradiation). The thermogravimetric curves showed three main mass losses and increased thermal stability for the triple (NaClO + UV + microwaves) modified sample. The UV-irradiated samples required less energy (enthalpy) to gelatinize as registered by the differential scanning calorimetry. Performing modification using microwaves resulted in starches of highly viscous pastes as recorded by the rapid visco analyser. All the starch gel samples presented thixotropic behaviour, in which pseudoplastic characteristics were adequately described by Ostwald-de Waele and Herschel-Bulkley models. Rheological evaluation also revealed that one-step modified starches could produce stronger gels than the native one. Lower degree of relative crystallinity and a wide range of granule sizes were demonstrated by X-ray diffraction patterns and scanning electron microscopy. The colour measurement revealed the brightening and browning action of NaClO and microwaves, respectively. [ABSTRACT FROM AUTHOR]

Commercial lipase from Burkholderia cepacia is immobilized on functionalized multi-walled carbon nanotubes (MWNT-COOH and MWNT-OH) provided by a physical adsorption. The immobilization processes for the carbon nanotubes are defined using immobilization time (0-30 min) and distinct adsorbent:adsorbate ratios (1:4, 1:7, and 1:10) with lipase loading of 100, 175, and 250 mg, respectively. The characterization of the immobilized preparations, the free lipase, and the pure nanotubes (MWNT-COOH and MWNT-OH) indicate that the lipase adsorption is increased. Thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy are used. The specific surface area, pore volumes, and average pore diameters are determined by nitrogen adsorption-desorption isotherms. For the pure lipase, in the range between 40 and 300 °C, the micrograph is acquired. Experimental results clearly show an effective lipase adsorption in a lower period of time (5 min) in MWNT-COOH and MWNT-OH as well as a decrease in the surface area (98.30-45.9(86) ± 2.5 and 97.61-37.71 ± 3.3(7) m2 g−1) and the pore volume (0.48-0.25 ± 0.01 and 0.39-0.24 ± 0.05 cm3 g−1), indicating that functionalized multi-walled carbon nanotubes can be successfully used as enzyme support. [ABSTRACT FROM AUTHOR]

A novel phase-change composites based on silicone rubber (MVQ) containing n-octadecane/poly (styrene-methyl methacrylate) microcapsules were successfully obtained by mixing energy-storage microcapsules into MVQ matrix using three preparation methods. The effect of microcapsules content on thermal property of the composites was investigated by thermogravimetric analysis. The mechanical properties of the composites prepared by three methods were also investigated. The morphology and thermal properties of the composites were characterized by scanning electron microscopy (SEM), differential scanning calorimetry, and thermal response. Thermal and mechanical properties of the composites were excellent when the microcapsules were added into room temperature vulcanized silicone rubber with 2 phr (per hundred rubber) content and cured at room temperature. The composites were proved to have good energy-storage performance with 67.6 J g−1 enthalpy value. [ABSTRACT FROM AUTHOR]

The thermal features of potato, banana, corn and cassava starches were correlated with structural properties. These starches were characterized by SEM, XRD, FTIR-ATR, DSC and TG. The crystalline index of starches was evaluated, and the banana starch presented the highest. Infrared ratios of amorphous/crystalline regions were close to XRD data for potato and corn starches. The amylose ratio was correlated with Tg and gelatinization measurements by DSC, with some restrictions. TG experiments demonstrated that the crystalline array affects the thermal stability of starches, but the major component is the amylose ratio. [ABSTRACT FROM AUTHOR]

Abstract: In the present study, silver nanoparticles were coated on different coir fibers to see their improvements in thermal behavior against the raw coir fiber. The fibers taken for the study are raw coir, parent coir (PC), modified coir-1 (MC1), modified coir-2 (MC2), silver nanoparticles (AgNPs)-coated PC and MC fibers. All the fibers were subjected to FESEM along with line scans of EDS, thermo gravimetry, differential thermal gravimetry and differential scanning calorimetry (DSC) analyses to observe the size of AgNPs and their responses to thermal behaviors, respectively. FESEM along with line scans of EDS shows the size of AgNPs varies from 40 to 210 nm in the coated fiber. The temperature of degradation (Tf (°C)) of AgNPs-coated coir increases significantly compared to PC and MCs. DTA and DSC analyses indicate higher thermal stability of silver-coated fibers over PC and MCs. In general, all the fibers show higher thermal stability over raw fiber and when coated fibers were compared, the thermal stabilities follow the order MC2 > MC1 > PC. It was also found that increase in the concentration of silver during coating further increases the thermal stability in all the cases without changing the order.Graphical Abstract: [ABSTRACT FROM AUTHOR]

This study aims to assess the thermal properties of mixtures of sugarcane bagasse and iron(III) nitrate in the following proportions (mass/mass): 1/2, 1/1, and 2/1, using thermogravimetry/differential thermogravimetry and differential thermal analysis. These thermoanalytic techniques were performed to assess the best temperatures for the heat treatment of the mixtures for the subsequent production of the carbonaceous material/iron oxide composites and their behavior at different temperatures. According to thermal analysis, the decomposition profile of the mixture depends on the ratio of sugarcane bagasse to iron nitrate (BC/NF). The synthesized composites were characterized by X-ray diffraction, proving the formation of phases established from thermal analyses performed at 400, 500, and 600 °C. It was concluded that composites of the precursor mixtures may be produced to have different and interesting properties according to their application in sewage treatment processes such as adsorption. [ABSTRACT FROM AUTHOR]

Hyperbranched poly(ester)s (HBPE) possess attributes for applications in a number of areas which include platforms for controlled release of actives and as rheology modifiers and coalescent agents in coatings. For the latter applications, properties such as the glass transition temperature and thermal stability are important. A number of HBPEs were produced with varying composition, molecular weight, degree of branching and end-group functionality in order to determine the effect of each on the HBPE thermal and rheological properties. These materials were synthesized from trimethylolpropane and the difunctional acids; adipic, phthalic and terephthalic. The chemical structure of the resulting HBPEs was fully characterized, particularly by SEC and NMR, and the thermal properties by DSC and TG. The glass transition temperature was found to depend primarily on HBPE composition and end-group functionality. The prominent feature of the thermal degradation for the hydroxyl-capped HBPE was dehydrative ether formation while that for carboxyl-capped polymers was decarboxylation. [ABSTRACT FROM AUTHOR]

Shape-stabilized composite phase change materials composed of sebacic acid (SA) and MCM-41 were prepared by a facile blending and impregnating method. Various characterization techniques were carried out to characterize their structural and thermal properties, including thermogravimetry (TG) analyses and differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy. The XRD and FT-IR results indicated the interactions between SA and MCM-41, such as the capillary force and the hydrogen bonding, resulting in the confined crystallization process. As a result, the SA that was confined was amorphous. The TG analysis results showed that the presence of MCM-41 practically resulted in an overlapping of the two decomposition stages. The DSC analysis demonstrated that a decrease in the SA content was accompanied by a continuous decrease in the melting point and phase change enthalpy of the composites. [ABSTRACT FROM AUTHOR]

This work is mainly focused on study of thermal and thermomechanical properties of obtained bio-based polyurethane (coded as bio-PU) composites via using different types of bio-components (bio-glycol, modified soybean oil and sisal fiber) in the procedure. The chemical structure, morphology and mechanical properties were also investigated and described in this manuscript in order to know more perfect characterization of produced composites. The bio-based polyurethane matrix of composites was synthesized via prepolymer method. Bio-PU composites were produced by dispersing 5 and 15 mass% of sisal fibers into the polyurethane matrix during their synthesis. To investigate the thermal stability of sisal fibers and bio-PU composites, the thermogravimetric method (TG) was used. Thermomechanical tests were performed by means of dynamic mechanical analysis (DMA). Based on the results of thermomechanical analysis, it was found that the sisal fibers amount has the impact on storage and loss modulus. Chemical structure was confirmed by FTIR spectra. Mechanical results and scanning microscopy images of the composites showed good interfacial adhesion between sisal fibers and the bio-based PU matrix. [ABSTRACT FROM AUTHOR]

The thermal behavior of lavender and sage essential oils (EOs) and also that of their main components (camphor and 1,8-cineole) were studied by thermogravimetry (TG) at different scan rates under inert gas atmosphere up to about 140 °C. All the samples investigated undergo a single-step evaporation starting from ambient temperature without evidence of side decomposition processes. On the basis of the onset temperatures ( T ) extrapolated from the TG curves, the following increasing stability trend is assessed: However, the difference of T values among the first three samples was found to be slight. To the aim of assessing a thermal stability scale among the samples, a kinetic analysis of evaporation was performed. A first approach was based on a simple model-fitting kinetic method, widely used in the past for studying evaporation of EOs. The results were compared with those obtained with a more reliable approach based on the integral isoconversional method by Kissinger-Akahira-Sunose in which the activation energy ( E ) versus reaction extent ( α) plot of each sample was obtained. Because of the compensation effect, neither activation energy nor the pre-exponential factor, alone, could be considered to compare the stabilities. Lastly, the Arrhenius kinetic rate constant values at given temperatures within the experimental range were calculated, and camphor was found to be the more stable component, while lavender seems to vaporize faster than any other sample tested. [ABSTRACT FROM AUTHOR]

The thermal decomposition and de-hydroxylation process of dickite-potassium acetate (KAc) intercalated complex was studied using thermogravimetric (TG), differential thermal analysis (DTA), XRD and FTIR. The stability of intercalated complex was affected by heat treatment directly. The TG-DTA results showed that four changes had occurred at 64.5, 118, 301 and 406 °C, which can be attributed to (a) the loss of adsorbed water, (b) loss of the water linked to acetate ion in the layer of dickite, (c) decomposition of KAc, and (d) loss of water through de-hydroxylation, respectively. The XRD and FTIR results showed that when the heating temperature exceeded 400 °C, inner surface hydroxyls and inner hydroxyls lost gradually, generating amorphous meta-dickite. Further researches demonstrated that phase transition temperature of meta-dickite and mullite changed a lot through the intercalated KAc. [ABSTRACT FROM AUTHOR]

The kinetics of thermal dehydration of KCu[Fe(CN)]· nHO was studied using thermogravimetry for x = 0.0 and 1.0. Data from both non-isothermal and isothermal measurements were used for model-free kinetic analysis by the Friedman and KAS methods. The water content was determined to be n = 2.9-3.9, plus an additional ~10% of water, likely surface adsorbed, that leaves very fast when samples are exposed to a dry atmosphere. The determined average activation energy for 0.2 ≤ α ≤ 0.8 is 56 kJ mol. The dehydration is adequately described as a diffusion-controlled single-step reaction following the D3 Jander model. The determined dehydration enthalpy is 11 kJ (mol HO) for x = 0.0 and 27 kJ (mol HO) for x = 1.0, relative to that of water. The increase with increasing x is evidence that the HO molecules form bonds to the incorporated K ions. [ABSTRACT FROM AUTHOR]

Thermal decomposition, thermal conductivity, specific heat and flammability of polydimethyl siloxane (PDMS) resin and three PDMS-based systems with three different types of additives were studied using various thermo-analytical techniques. The additives were found to modify the thermal properties of PDMS to different extents. Among the three systems, highest specific heat and lowest thermal conductivity, desired for thermal protection application, were obtained for System I. The thermal stability of the three systems is in the order System I > System II > System III. Even though System III showed the lowest specific heat and highest thermal conductivity, due to its very high LOI among all other systems, the system finds application as a flame retardant. Thermogravimetric-mass spectroscopic analysis was carried out to find out the decomposition products. The major decomposition product was identified as hexamethylcyclotrisiloxane in all the systems. The decomposition kinetics of these systems was investigated by thermogravimetry using multiple heating rate methods, viz. Kissinger and Flynn-Wall-Ozawa. The kinetic parameters, viz. activation energy and pre-exponential factor, were derived using the two methods for all the systems. From the kinetic study, it is confirmed that the activation energy for the decomposition of the neat PDMS decreased as decomposition progressed, whereas the activation energy increased for the silicone composite systems. [ABSTRACT FROM AUTHOR]

Nanocomposites based on poly(3-hydroxybutyrate) (P3HB) and Cloisite30B were prepared by direct mixing in a co-rotating twin-screw micro-extruder. The X-ray diffraction method and transmission electron microscopy allowed to identify the nanostructure. Thermal properties of the obtained nanocomposites were investigated with the use of thermogravimetry (TG) and differential scanning calorimetry (DSC). TG analysis of nanocomposites showed that thermal stability of the obtained nanocomposites was higher by approximately 20 °C than the neat P3HB. The phase transitions such as the glass transition, the crystallization and the melting have been studied by the DSC. The influence of nanofiller's presence in the polymer matrix on glass transition, crystallization and melting processes of the material obtained was determined and compared with the neat P3HB. The clay addition to the polymer matrix made the increase of the degree of crystallinity and the increase of the degree of amorphous of semi-crystalline P3HB. Furthermore, mechanical properties such as impact strength, flexural strength and hardness were investigated and compared with unfilled P3HB. Obtained nanocomposites containing 1 mass/% of Cloisite30B have the best mechanical properties, better than the neat P3HB. [ABSTRACT FROM AUTHOR]

The isothermal oxidation process of red phosphorus (RP) was investigated by thermogravimetric analysis in the temperature range of 320-480 °C. The model-free, model-fitting and reduced-time plot methods were used to research the oxidation kinetics of RP. According to the d α/d t − α and model-free curves in different temperatures, the oxidation temperatures are divided into two ranges: lower temperatures (320-380 °C) and higher temperatures (390-410 °C). The apparent activation energy and oxidation controlling mechanisms in different temperature ranges are obtained. Besides, the trend of the oxidation rate with mass loss or temperature ranges is discussed. [ABSTRACT FROM AUTHOR]

In this study, silica sol (SiO sol) and KCO were used as flame retardants for wood. The synergistic effect of SiO sol and KCO on the flame retardancy, leaching resistance, and thermal properties of wood was investigated. The limiting oxygen index results revealed a significant improvement in the flame retardancy and leaching resistance of the wood sample treated with KCO and SiO sol using the double bath technique. The thermal analysis results showed that the synergistic effect of KCO and the SiO sol effectively prolonged the degradation of the wood sample during the charring stage and improved the stability of the char residue. The thermogravimetry-mass spectrometry analysis and scanning electron microscopy results showed that KCO catalyzed the degradation reaction of the wood sample at lower temperatures resulting in an increase in the water and carbon dioxide output, and the SiO sol formed a compact and melted barrier on the surface of the char residue, which hindered the transfer of heat and combustible gases in the condensed phase. Thus, the combination of KCO and SiO sol proves to be a promising flame-retardant system for wood. [ABSTRACT FROM AUTHOR]

Composites based on an epoxy resin, diglycidyl ether of bisphenol A and SiO nanoparticles, unmodified and surface-modified with a coupling agent 3-glycidyloxypropyltrimethoxysilane, were prepared. Successful modification of the nanoparticles was confirmed by infrared spectroscopy and combined differential scanning calorimetry and thermogravimetric analysis (DSC-TG). Composite materials were prepared by adding 0.5-5 phr (parts per hundred parts of resin) of modified and unmodified nanoparticles into the epoxy resin which was then cured with a poly(oxypropylene) diamine. Curing was followed by DSC, and cured materials were characterised by tensile and hardness testing. Morphology of fractured surfaces after tensile testing was investigated by scanning electron microscopy (SEM). Thermal stability of cured materials was studied by TG and their glass transition temperature determined by DSC. The presence of the filler was found not to influence the curing mechanism of the epoxy resin nor the degradation mechanism of the crosslinked epoxy-amine matrix. Glass transition exhibits a small shift to higher temperatures in composites, which also exhibit increased char formation-at lower filler content for the composite with unmodified nanoparticles and at higher for the one with modified nanoparticles. All composites show improved mechanical properties in comparison with the neat epoxy. For the unmodified particles, strength and modulus are particularly improved at lower nanofiller content due to their better dispersion, as observed by SEM. The modified nanoparticles contributed to a significant increase in elongation at break, increasing the toughness of the cured resin while retaining its strength and without having an adverse influence on the modulus. [ABSTRACT FROM AUTHOR]

Poly(lactic acid) (PLA)-based nanocomposite films were prepared by incorporating zinc oxide (ZnO) (<50 and <100 nm) and bimetallic Ag-Cu alloy (<100 nm) nanoparticles (NP), and polyethylene glycol as a plasticizer via a solvent casting method. Thermal properties of the nanocomposites films were investigated using differential scanning calorimeter and thermogravimetric analyzer. The addition of 20 % PEG to the neat-PLA decreased the glass transition temperature ( T) significantly from about 60 to 17 °C, whereas the melting temperature ( T) did not drop significantly. Metallic nanoparticles increased the T; however, Ag-Cu alloy exhibited a greater increase than ZnO nanocomposite films. Particle size of ZnO NP did not show significant difference in the T values of the films. The T value of the nanocomposite films was not influenced by the NP. The addition of plasticizer initiated the crystallization (cold and melt) of the PLA/PEG blend, which was substantially improved by the incorporation of NP in the composite films, in particular, 1 mass% loading. Non-isothermal crystallization was significantly affected by the cooling and heating rates. Thermogravimetric analysis data indicated that only Ag-Cu alloy could improve the thermal stability of nanocomposite films. Furthermore, nanoparticles significantly influenced the UV barrier and the transmittance of plasticized films. [ABSTRACT FROM AUTHOR]

A thermal gravimetric analysis was studied for the new metal mixed-ligand complexes of copper(II), nickel(II), cobalt(II), and zinc(II) metals formed with glutamic acid as a primary ligand and nitrilotriacetic acid (HNTA) as a secondary ligand which have been characterized by their elemental analysis, magneto-chemical measurements, Fourier transform infrared (FTIR), UV-Vis spectrophotometer, thermal gravimetric analysis, and mass spectroscopy studies. Glutamic acid in these complexes acts as a bidentate ligand, coordinating through the one nitrogen of the amino group and one oxygen of the carboxylate group, whereas nitrilotriacetic acid shows a tridentate nature, and the coordination occurs through two carboxylate oxygen and one nitrogen of the amino group. Water molecules satisfy the remaining coordination positions. The complexes have been suggested to show geometry of an octahedral symmetry. The results were indicated that the mixed complexes were isolated in 1:1:1 molar ratio (metal-glutamic-HNTA), and the molecular structures were suggested to be [M(glutamic)(HNTA) (HO)]·(2-1.5)HO. The antimicrobial activities of our prepared complexes evaluated against Escherichia coli, Staphylococcus aureus, Candida albicans, and Aspergillus flavus (isolates from Micro-analytical Center, Faculty of Science, Cairo University) were investigated. Also, our prepared complexes were evaluated for their in vitro anticancer activity against hepatocellular carcinoma. In addition, the mass loss inhibition effects for copper and aluminum metal plates by our prepared complexes in 1 M HCl were studied. [ABSTRACT FROM AUTHOR]

The new energetic compound 1 H-pyrazole-1-carboxamidine dinitramide (PACADN) was synthesized by the reaction of silver dinitramide with 1 H-pyrazole-1-carboxamidine hydrochloride. Its structure was confirmed by single-crystal X-ray diffraction, elemental analysis and Fourier transform infrared, ultraviolet-visible and nuclear magnetic resonance spectroscopy analyses. PACADN crystallizes in the orthorhombic space group Pnna. The thermal decomposition was studied with differential scanning calorimetry, thermogravimetry analysis and thermogravimetric tandem infrared spectrum. The results indicated that PACADN exhibits good resistance to thermal decomposition up to 433 K and has 90.24 % mass loss between 433 and 523 K by undergoing exothermic decomposition. The kinetic parameters of the thermal decomposition of PACADN were also obtained from the derivative thermogravimetry analysis data using Kissinger's method, with E = 143.2 kJ mol. Moreover, the detonation velocity and detonation pressure of PACADN were calculated as 7.2 km s and 21 GPa by applying the Kamlet-Jacobs (as follows). [ABSTRACT FROM AUTHOR]

In this study, a natural fiber extracted from the palm tree was used as reinforcement for acrylonitrile butadiene styrene (ABS) matrix composites. Palm fiber (PF)-reinforced ABS (PF-ABS) composites were prepared via injection molding machine. Three sets of samples were prepared for three different mass% (5, 10 and 20 %) of fiber contents. The effect of fiber addition in composite along with the age and different edges of the palm fiber on thermal properties was evaluated with the help of thermogravimetric/differential thermogravimetric, differential thermal analyses and thermomechanical analysis. Thermal stability of the palm fiber is more for 11- to 20-year age group than 5- to 10-year age group for both thin and thick edges of palm fiber. The thermal stability of PF-ABS composites for different mass percentage of fiber is more or less same except 10 % fiber content in PF-ABS composites. [ABSTRACT FROM AUTHOR]

The thermal reaction properties of the aluminum nanoparticles/copper (II) oxide nanoparticles/poly(vinylidene fluoride) (Al-NPs/CuO-NPs/PVDF) nanocomposite (mass ratio of Al-NPs/CuO-NPs/PVDF = 20/60/20) were investigated by means of thermogravimetry-differential scanning calorimetry-mass spectrometry (TG/DSC-MS) and X-ray diffraction (XRD) analysis. Al-NPs/PVDF (mass ratio of Al-NPs/PVDF = 50/50) and CuO-NPs/PVDF (mass ratio of CuO-NPs/PVDF = 75/25) nanocomposites were also prepared as a comparison. It is observed that PVDF in the Al-NPs/PVDF nanocomposite acts as an oxidizer. The fluorine ions/fluorinated gases formed at elevated temperatures react with the AlO shell leading to the formation of aluminum fluoride (AlF). The oxide shell is degraded from the reaction between fluoride ions and AlO, leaving the core Al available for reaction with fluorine ions/fluorinated gases. H ( m/z = 2), OH ( m/z = 17), HO ( m/z = 18), HF ( m/z = 20), CF ( m/z = 31) and CHF ( m/z = 33) fragments were detected in the gaseous products. For CuO-NPs/PVDF nanocomposite, oxygen was released due to the decomposition of CuO to CuO and then Cu metal, oxidizing hydrocarbon groups in PVDF. Species of OH ( m/z = 17), HO ( m/z = 18), CO ( m/z = 44), CHF ( m/z = 45) and HF ( m/z = 20) were detected in the gaseous products. The final reduction product of CuO is Cu metal. It is observed that PVDF in the Al-NPs/CuO-NPs/PVDF nanocomposite acts as both oxidizer and reducer in the thermal decomposition. Below 550 °C, PVDF is oxidized by CuO-NPs and oxidizing Al-NPs at the same time, resulting mass reduction. After 550 °C, the remaining Al-NPs and copper (I)/copper (II) oxide will proceed the exothermic solid-state thermite reaction. OH ( m/z = 17), HO ( m/z = 18), CO ( m/z = 44), CHF ( m/z = 45) and HF ( m/z = 20) were the main products of the decomposition of Al-NPs/CuO-NPs/PVDF nanocomposite. [ABSTRACT FROM AUTHOR]

Copper chromite is a well-known burn rate modifier for the combustion of composite solid propellants. In this study, basic copper ethylamine chromate (CEC), a new precursor for copper chromite catalyst, was synthesized by precipitation method. The thermal decomposition of the precursor was followed by thermogravimetry-mass spectroscopy (TG-MS) and X-ray diffraction techniques and compared with that of copper ammonium chromate, a conventional precursor for copper chromite catalyst. TG-MS analysis for the decomposition of CEC revealed that the decomposition starts with the liberation of ethylamine. The change in enthalpy for the decomposition reaction of copper ethylamine chromate was higher than that of copper ammonium chromate due to the oxidation of ethyl group. The reducing atmosphere created by the presence of carbon during the decomposition of CEC produced a mixture of Cu, CuCrO, CuCrO and CuO, while the oxidizing atmosphere of copper ammonium chromate produced a mixture of CuCrO and CuO. Mechanistic study based on Criado and Coats-Redfern methods showed that CEC follows random nucleation (F1) mechanism as the rate-determining step for the thermal decomposition process. [ABSTRACT FROM AUTHOR]

Metal cutting fluids (MCFs) or cutting fluids are widely applied industrial products traditionally based on hydrocarbons. However, hydrocarbon-based cutting fluids have low thermal stability and tend to vaporize during application, causing environmental and human health problems. One of the most promising cutting fluids is based on vegetable oils, due to the high level of biodegradability and low toxicity, although vegetable oils have unsaturations that reduce their oxidation stability. This work evaluated the thermal and rheological behaviors of two chemically modified cottonseed oils: epoxidized fluid and hydroxylated fluid, besides unmodified cottonseed oil and commercial cutting fluid. The thermogravimetric analysis showed that the commercial cutting fluid starts volatization at low temperature (100 °C) while all cutting fluid derivatives of cottonseed oil have thermal resistance higher than 300 °C under inert atmosphere. All cutting fluids had Newtonian behavior (power-law index = 1), with viscosity up to 0.12 ± 0.05 Pa s. The small differences indicate similar lubricity. As expected, the viscosity decreased with temperature for all fluids. The apparent activation energies decreased in the order commercial cutting fluid > epoxidized fluid > cottonseed oil > hydroxylated fluid. Lower apparent activation energy of hydroxylated fluid indicated better heat transfer of this fluid due to better convection. Real drilling experiments indicated lower tool wear with the use of the epoxidized fluid. [ABSTRACT FROM AUTHOR]

During oxy-fuel combustion, the gas composition inside the boiler differs greatly from that of conventional combustion with air, involving consequences for different aspects in fuel combustion. Research on oxy-fuel combustion is needed to understand which factors influence the process, especially for coal and biomass co-firing. In this study, the combustion behaviour of coal/biomass blends was determined by thermogravimetric studies (TG) with different CO/O mixtures and compared with similar results for conventional combustion. This approach determines the appropriate conditions for the oxy-fuel combustion for future studies that will be carried out in lab- and bench-scale combustors. One sub-bituminous coal (Puertollano coal) and two Spanish biomasses (olive grove and thistle) were the fuels selected for the study. The combustion behaviour of each pure fuel and several coal/biomass blends, under air and oxy-fuel conditions (70 %CO-30 %O, 60 %CO-40 %O), was studied. Results obtained for the pure fuels have shown that the temperatures of maximum reaction rate, T, determined under oxy-fuel combustion were lower than those found during conventional combustion. Similar pattern was encountered for the different coal/biomass blends studied (varying from 80 % coal/20 % biomass to 20 % coal/80 % biomass), with a more reactive behaviour in oxy-fuel conditions than in conventional air combustion. The values of temperatures at maximum mass loss, T, obtained for these blends in an oxy-fuel atmosphere were 100-200 °C lower than the values found for the air atmosphere. T values determined for the blends were also dependent on the oxy-fuel conditions, with larger differences observed with the 60 %CO-40 %O mixture than with the 70 %CO-30 %O atmosphere with respect to air combustion. However, the greatest decreasing effect compared to air of biomass addition on T values was found for the blend with the lowest biomass content (20 % biomass w/w). [ABSTRACT FROM AUTHOR]

Polymer monoliths with highly developed porous structure have been successfully synthesized by polymerization of 1-vinyl-2-pyrrolidone with trimethylolpropane trimethacrylate and divinylbenzene. During the copolymerization, the mixtures of toluene/n-dodecane and toluene/decan-1-ol were used as pore-forming diluents. The thermodynamic quality of the porogen mixtures strongly influences the process of the pore formation. By changing the ratio of non-solvating and solvating diluents, monoliths with surface area from 57 to 650 m g and pore diameters from 4 to 51 nm were prepared. Thermal properties of the obtained materials were investigated by the means of thermogravimetry and differential scanning calorimetry. It was found that they do not depend on the diluent composition but are determined by the type of cross-linker used in the synthesis. [ABSTRACT FROM AUTHOR]

Thermogravimetry (TG) and derivative thermogravimetry (DTG) have been applied to the investigation of the thermal behavior of the compounds Cu(2-Clbz)(denia)(HO) (I), Cu(2-Brbz)(denia)(HO) (II), and Cu(3-Brbz)(denia)(HO) (III), where 2-Clbz and 2-Brbz and 3-Brbz = 2-chloro-, 2-bromo- and 3-bromobenzoate anions, denia = N,N-diethylnicotinamide, HO = water molecules. Thermal decomposition of all studied compounds proceeds in three steps. Heating of the compounds first results in the release of water molecules. The final product of thermal decomposition of studied complexes was CuO. The thermal stability of the complexes can be ordered in the sequence: (II) < (I) < (III). IR data suggest unidentate coordination of benzoate anions to Cu(II) in complexes (I)-(III). [ABSTRACT FROM AUTHOR]

The aim of the work was to determine the impact of ultraviolet (UV) irradiation on thermal properties of polylactide-based nanocomposites in the form of a film. Polylactide nanocomposites composed of an organoclay (Nanofil2) and with or without a poly(ε-caprolactone) were exposed to UV radiation in air at a wavelength of maximum 254 nm. Thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) were used in order to investigate the thermal properties of samples during the process of photodegradation. Influence of Nanofil2 quantity and the presence of poly(ε-caprolactone) on thermal properties of polylactide-based nanocomposites during UV exposure has been discussed. It has been established that introduction of Nanofil2 as a nanofiller and a compatibilizing agent into polylactide matrix can affect photodegradation of studied materials. The results of DSC analysis indicate that the rate of degradation process was decreased in the presence of modified montmorillonite. [ABSTRACT FROM AUTHOR]

In this paper, the synthesis and characterization of thermal properties of porous copolymers 1-vinyl-2-pyrrolidone with trimethylolpropane trimethacrylate are presented. They were obtained by suspension polymerization as a pure polymers or composite materials with different inorganic fillers. The influence of the type of filler on the textural and thermal properties was investigated in details. It was found that the value of the porous surface area of composites is much lower than in the case of pure copolymers. Thermal properties of the obtained materials were investigated by the means of thermogravimetry and differential scanning calorimetry. [ABSTRACT FROM AUTHOR]

Thermoreversible networks obtained by the Diels-Alder cycloaddition reaction of poly(vinyl furfural) with urethane bismaleimides containing polyether chain were synthesized. The formation of the networks was confirmed by attenuated total reflectance in conjunction with Fourier transform infrared spectroscopy (ATR-FTIR). The materials thermal properties were investigated using differential scanning calorimetry (DSC) and a coupling of dynamic thermogravimetry with Fourier transform infrared spectroscopy and mass spectrometry (TG-FTIR-MS) for pyrolysis behaviour under nitrogen atmosphere. A thermal decomposition mechanism of the networks and poly(vinyl furfural) was discussed via evolved gas analysis. The thermoreversibility of the networks was demonstrated by the presence of the endothermic peak characteristic to the retrodienic process on the DSC heating curves and also the appearance of the exothermic peak, due to the dienic process, on the DSC cooling curve. The dynamic contact angle and free surface energy values of the networks were determined. Measures of the heterogeneity and roughness of the surfaces suggested that the surfaces of the networks' films are more homogenous than the initial poly(vinyl furfural) surface. Dynamic water vapour sorption studies were conducted. [ABSTRACT FROM AUTHOR]

Understanding the role of chemical burn additives on modifying the toxic gaseous constituents and thermal behavior of reconstituted tobacco sheet (RTS) has recently taken center stage through a number of initiatives. In this current study, the effects of ammonium chloride (AC), ammonium sulfate, diammonium phosphate, and monoammonium phosphate on the formation of evolved gaseous products, specifically carbonyl compounds and thermal behavior were investigated. Results on cigarette smoking tests revealed that ammonium salt was a potential burn additive to reduce carbonyl compounds delivery in the cigarette mainstream smoke of RTS. The yield per puff of carbonyl compounds of pure RTS was decreased from 247.8 µg to 133.30 µg with the incorporation of AC. Thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) were used to investigate the thermal decomposition of RTS. TG results revealed that the incorporation of ammonium salt into RTS could improve the thermal stability of RTS. The DSC results showed that the maximum exothermic peak was drastically decreased with the addition of ammonium salt, for example, from 14.8 mW mg of pure RTS to 10.27 mW mg of AC-RTS. Results on Fourier transform infrared spectrometer (FTIR) which was employed to investigate the generation of evolved volatile products showed that these four ammonium salts as burn additives were efficiently high enough to decrease the formation of gaseous products. From our findings, compared with the virgin RTS and other three modified RTS, AC-RTS could significantly decrease the yields of nicotine and phenolic compounds in the cigarette mainstream smoke of RTS. [ABSTRACT FROM AUTHOR]

This study focused on preparation and thermal properties of poly(stearyl methacrylate) shell (PSMA) microcapsules containing n-octadecane as a phase change material (PCM). Pentaerythritol triacrylate (PETA) and divinylbenzene (DVB) were employed as crosslinking agents. The surface morphologies, particle sizes, and distributions of the microencapsulated phase change material (microPCM) were studied by scanning electron microscopy. The thermal properties, thermal reliabilities, and thermal stabilities of the microPCMs were investigated by differential scanning calorimetry and thermal gravimetric analysis. The microPCM with DVB exhibits higher phase change enthalpies of melting (87.9 J g) and crystallization (94.8 J g) and a greater thermal stability in comparison with the microPCM with PETA. The phase change temperatures and enthalpies of the microPCMs varied little after thermal cycles. Thermal images showed that the gypsum board with PSMA/ n-octadecane microPCM possessed temperature-regulated property. Therefore, microencapsulated n-octadecane with PSMA as shell has good thermal energy storage and thermal regulation potential. [ABSTRACT FROM AUTHOR]

Epoxy resins are well-known materials that show beneficial properties, such as high tensile strength and modulus, good adhesive properties, low cost, and ease of processing and environmental advantages. However, epoxy resin adhesive has no characteristic of thermal storage. Latent heat storage is one of the favorable kinds of thermal energy storage methods considered for energy saving and thermal efficiency in various fields, such as solar air conditioning systems and buildings. So we prepared thermal-enhanced epoxy resin adhesive by using PCM. This paper addresses the effects of n-hexadecane and sodium lauryl sulfate on the thermal properties and chemical properties of epoxy resin adhesive and HEAC, using differential scanning calorimetry, thermal gravimetric analysis, and Fourier transform-infrared spectroscopy. Also, we evaluated the applicability of composite epoxy resin adhesive to wood-based flooring using n-hexadecane, through measurement of bonding strength from universal testing machine analysis. [ABSTRACT FROM AUTHOR]

The purpose of this study is to research the thermal properties of spreads with maltitol. Thermal characteristics of spreads depend on process parameters (temperature, mixer speed rotation). Spreads are produced at different temperatures (30, 35, and 40 °C) and mixer speed rotation (1, 1.33, and 1.67 Hz). The thermogravimetric method shows the peak position and determinate the spread composition. The temperature decomposition of sucrose and maltitol is two stages (two peaks), and palm fat has a single stage decomposition (one peak). Maltitol peak is dominant for spreads containing 100 and 70 % maltitol as a sweetener. This peak is sharper than sucrose peak and the inflection point is more expressed. Shape and the position of these peaks in spreads are modified. Peaks of maltitol, palm fat, and sucrose in spreads are lower and wider because of the grinding process and the interaction between spread ingredients. Increasing the process parameters (temperature, mixer speed rotation), temperatures of these peaks are higher (closer to temperature peak of pure ingredients). The dominant parameter is mixer speed rotation. The most thermally stable spreads with any amount of maltitol are produced at a temperature of 40 °C and high mixer speed rotation (1.33 and 1.67 Hz), while the least stable maltitol spreads are produced at minimum process parameters (30 °C, 1 Hz). [ABSTRACT FROM AUTHOR]

Thermal behavior of waxy oils is investigated using the techniques of thermogravimetric (TG) analysis and differential scanning calorimetry (DSC). Model waxy oils and real waxy crude oils are utilized. Decomposition temperatures of waxy oils are obtained using TG analysis. The effects of thermal history, wax content, and additive on the gelation process of waxy oils are investigated using DSC. The DSC method provides a measure of wax solubility as well as solid fraction. An integration method and a computation method are utilized to predict solid fraction. In addition, wax crystallization onset points are obtained at the cooling rates ranging from 1 to 20 °C min. Similarly, wax dissolution endset points are obtained at heating rates ranging from 1 to 20 °C min. Extrapolated onset and endset points yield wax precipitation temperature and wax dissolution temperature, respectively. Subsequently, wax solubility curves are obtained using thermodynamic computations. A wax precipitation temperature method and a wax dissolution temperature method combine thermodynamic phase behavior with onset/endset points to predict solid fraction. Both the wax precipitation temperature method and the wax dissolution temperature method can predict solid fraction of waxy oil samples. The wax precipitation temperature method and the wax dissolution temperature method are accurate when the temperature is close to the wax appearance temperature. A heat-integration method provides accurate values of the solid fraction at temperatures significantly below the wax appearance temperature. Therefore, integration method and wax precipitation temperature/wax dissolution temperature method are combined to predict solid fraction. The effect of solid fraction on yield stress is also investigated using differential scanning calorimetry and rheometry. Finally, a new solid fraction dependent gel strength model is obtained for shut in and restart of waxy crude oil pipelines. [ABSTRACT FROM AUTHOR]

Poly(vinylidene fluoride)/Pb(ZrTi)O,([PVDF]/[PZT]) composites of volume fractions x and (0-3) type connectivity were prepared in the form of thin films. PZT powders with average grain sizes of 0.2, 0.84, and 2.35 μm in different volume fraction of PZT up to 40 % were mixed with the polymeric matrix. The influence of the inorganic particle size and its content on the thermal degradation properties of the composites was then investigated by means of thermo-gravimetric analysis. It is observed that filler size affects more than filler concentration the degradation temperature and activation energy of the polymer. In the same way and due to their larger specific area, smaller particles leave larger solid residuals after the polymer degradation. The polymer degradation mechanism is not significantly modified by the presence of the inorganic fillers. On the other hand, an inhibition effect occurs due to the presence of the fillers, affecting particularly the activation energy of the process. [ABSTRACT FROM AUTHOR]

The thermal behaviour of natural rubber/acrylonitrile butadiene rubber (NR/NBR) was studied using thermogravimetry (TG) and differential scanning calorimetry (DSC) in terms of blend ratio, crosslinking systems, fillers and compatibilizer (neoprene) were analyzed. The presence of NBR markedly increases the thermal stability of their blends and it lies in between NR and NBR. DSC studies revealed the thermodynamic immiscibility of the NR/NBR blends by the presence of two distinct glass transition temperatures and the immiscibility was prominent even in the presence of a compatibilizer. [ABSTRACT FROM AUTHOR]

The physicochemical characterization and thermal profile of honeys produced by stingless bees are poorly known, mainly due to the high diversity of flora mellifera and to the low production that is inherent of these species. The objective of this study was to determine the physicochemical characteristics of five samples of honey from bees from the species Melipona seminigra merrillae of Amazonas State, Brazil. The thermal degradation profile of these honey samples was evaluated by thermogravimetry in order to contribute with the establishment of a quality standard of honeys produced from Brazilian stingless bees. Thus, the following analyses were performed: reducing sugars, moisture, hydroxymethylfurfural, protein, ash, pH, and acidity. The results showed that the current legislation concerning the honey of Apis mellifera is not an appropriate standard for all the properties analyzed, reinforcing the need for a honey standard including the honeys of all Brazilian bees. The honey samples displayed similar thermal degradation profiles, with the thermal process starting at room temperature and ending at a temperature next to 600 °C. [ABSTRACT FROM AUTHOR]

In this study, the effects of four types of clay minerals on the thermal decomposition of 12-aminolauric acid (ALA) were investigated. The decomposition temperature of ALA in ALA-clay complexes was in the range of 200-500 °C. The derivative thermogravimetry results indicated that all clay minerals exhibited catalytic activity on the decomposition of ALA. Pure ALA decomposed at approximately 464 °C, a temperature higher than the decomposition temperature of ALA in the presence of clay minerals. The decomposition temperature of ALA in different ALA-clay complexes follows the order illite (452 °C) > kaolinite (419 °C) > rectorite (417 °C) > montmorillonite (400 °C). This order is negatively correlated with the amounts of solid acid sites in the clay minerals, indicating that ALA is catalyzed by the solid acid sites in these minerals. [ABSTRACT FROM AUTHOR]

The viscoelastic characterization and thermal stability property of some multifunctional epoxy/anhydride systems cured at different schedules were investigated by dynamic mechanical thermal analysis (DMTA) in single cantilever mode at fixed frequency, and by non-isothermal thermogravimetric (TG) analysis, respectively. According to the DMTA results, three obviously different glass transition temperatures ( T), were observed, among which TGDDM/MHHPA system exhibits the largest T. While from the TG curves, the results of the mass loss and thermal stability showed that, after cured for a prolonged duration, the TGDDM/MHHPA system possessed the most excellent performance in heat resistance. [ABSTRACT FROM AUTHOR]