TG FTIR Research Articles

Pyrolysis characteristics of oil shale semi-coke and its extracted bitumen

Fushun oil shale semi-coke and its extracted bitumen were prepared for analyzing their pyrolysis characteristics by TG–DTG, TG–FTIR, and Py–GC/MS. Semi-coke was the residue of oil shale pyrolyzed to 450 °C, and extracted bitumen was the organic matter extracted from semi-coke with [Bmim]Cl/NMP mixed solvents. Gaussian fitting method was used to analyze the proportions of bond cleavage reactions occured during the pyrolysis to 700 °C at a heating rate of 20 °C/min. Results showed that 3–4 kinds of bond cleavages were mainly involved. The outstanding pyrolysis behaviors were contributed by the cleavages of CalCal and weak bonds (including volatilization). The kinetic parameters based on Coats–Redfern method were calculated from the points for each pyrolysis stage and bond cleavage reaction. The evolution processes of typical gaseous products and distributions of flash pyrolysis products were displayed in detail, exhibiting the prominent roles of aliphatic compounds, CH4, and CO2. Moreover, the releases of the typical gaseous products for semi-coke tended to occur at higher temperatures.

Mechanism of Two Typical Binders BR and F2604 on Thermal Decomposition of HMX.

DSC–TG–FTIR–MS coupling technology was used to study the mechanism of two typical binders, that is, BR and F2604, on the thermal decomposition behavior of the HMX crystal. The results show that both BR and F2604 can induce premature decomposition of HMX and increase the activation energy of HMX. Especially in the case of HMX/BR particles, the decomposition temperature is the lowest, but the activation energy is the highest. Based on the results of DSC–TG–FTIR–MS, it is found that the rapid mechanism of binder and active intermediate products inhibits the reaction of relatively inert intermediate products and prolongs the continuous generation time of gas products in the composite particles, which delays the decomposition of HMX to a certain extent. This study is helpful for us to better understand the thermal decomposition behavior of HMX composite particles and provides reference for the application of high-energy composites.

Assessment of the thermal hazards and oxidization mechanism of coloured corn starch dust by TG–FTIR

Starch is widely used in industrial production and in every life, and an increasing number of accidents of starch dust burning and explosions are occurring and have caused serious casualties and economic losses. Previous studies on the oxidative properties and microscopic characterization of coloured corn starch dust have been less systematic than the present study. To prevent coloured corn starch dust explosion accidents more effectively, thermogravimetry and Fourier transform infrared spectroscopy were applied to study the oxidation characteristics of coloured corn starch dust. Seven characteristic temperatures were determined from the thermogravimetric curves and derivative thermogravimetric curves of coloured corn starch dust. The entire oxidation process of coloured corn starch dust was divided into five stages, and a 60% mass loss occurred in the rapid oxidation stage. Three iso-conversion methods were used to calculate the apparent activation energy (Ea) and pre-exponential factor (A) at different oxidation stages. The value of Ea was found to be related to the difficulty of the reaction, and it had a positive correlation with lnA. Six kinds of gases were detected during the oxidation process. The oxidation mechanism was further analysed by the macro and micro characterization of the oxidation process. The findings provide a theoretical basis for preventing and controlling explosion accidents that involve coloured corn starch dust.

Green synthesis of niflumic acid complexes with some transition metal ions (Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II)). Spectroscopic, thermoanalytical and antibacterial studies

New complexes of Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) ions with niflumic acid (Hnif) were obtained in solid state using a green synthesis method and their physico-chemical properties, thermoanalytical behaviour in air and nitrogen as well as antibacterial activity were studied. Employing the results of elemental analysis (EA), complexometric titration with EDTA and TG/DTG-DSC analysis it was established that a minimal formula for the obtained compounds is M(nif)2·nH2O (where M means metal ion, nif is niflumate ion and n = 1–2.25). The exception is the complex with Fe(III) ions of formula Fe(nif)3·H2O. It was concluded that niflumate ligands bind to metal ions in two different manners. TG/DTG-DSC analysis showed that thermal decomposition of the obtained compounds is a multi-stage process depending on the metal ion and atmosphere in which was conducted. Based on the detailed DSC analysis it was shown that the dehydration of these compounds proceeds in two steps. By the use of the coupled TG–FTIR–MS techniques the decomposition pathways of the synthesized compounds were examined and the gaseous products released during thermal oxidation and pyrolysis of the complexes were identified. The antibacterial study showed an increase in the activity of some of the obtained complexes in comparison to the ligand. The complex with Zn(II) ions has the most effective antibacterial activity against both E. coli and P. aeruginosa. The MIC values for this compound against E. coli was 31-fold lower than for niflumic acid. Furthermore, this compound was 5- and 1.25-fold more potent than chloramphenicol (MIC = 0.50 mg mL−1) and kanamycin (MIC = 0.12 mg mL−1) that are the reference drugs against P. aeruginosa. The complexes with Mn(II), Fe(III) and Co(II) ions showed antibacterial activity against Gram positive bacteria (S. aureus) and the MIC values for these compounds were respectively 10-, 3.4-, 2.5-fold lower than for niflumic acid.

Py-FTIR-GC/MS Analysis of Volatile Products of Automobile Shredder Residue Pyrolysis.

Automobile shredder residue (ASR) pyrolysis produces solid, liquid, and gaseous products, particularly pyrolysis oil and gas, which could be used as renewable alternative energy resources. Due to the primary pyrolysis reaction not being complete, the yield of gaseous product is low. The pyrolysis tar comprises chemically unstable volatiles before condensing into liquid. Understanding the characteristics of volatile products will aid the design and improvement of subsequent processes. In order to accurately analyze the chemical characteristics and yields of volatile products of ASR primary pyrolysis, TG–FTIR–GC/MS analysis technology was used. According to the analysis results of the Gram–Schmidt profiles, the 3D stack plots, and GC/MS chromatograms of MixASR, ASR, and its main components, the major pyrolytic products of ASR included alkanes, olefins, and alcohols, and both had dense and indistinguishable weak peaks in the wavenumber range of 1900–1400 cm−1. Many of these products have unstable or weaker chemical bonds, such as =CH–, =CH2, –C=C–, and –C=CH2. Hence, more syngas with higher heating values can be obtained with further catalytic pyrolysis gasification, steam gasification, or higher temperature pyrolysis.

Thermal Characteristics, Kinetics, and Volatility of Co-Combustion of Sewage Sludge and Rice Husk

This work focused on the evaluation of co-combustion of sewage sludge (SS) and rice husk (RH) using thermogravimetric–Fourier transform infrared spectrometry method (TG–FTIR). The thermal behavior was assessed through the combustion characteristic, interaction, kinetics, and gaseous product characteristics. The (co-)combustion process was divided into three stages. Index D exponentially increased as RH blending ratio increased and index S also increased from 10 to 70% RH blending ratio, indicating that the combustion behavior was improved by the RH blending. The activation energy was evaluated by two model-free iso-conversional methods: Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS). The minimum value of average activation energy among blends was obtained at sample with 30% RH blending, which was 103.31 kJ/mol by FWO and 97.81 kJ/mol by KAS. Several typical gaseous products and functional groups were detected by FTIR spectrum. The results showed that CO2 was the main volatile and its yield increased with the RH blending ratio.

Thermal Kinetics of a Lignin-Based Flame Retardant.

In order to improve the thermal property of epoxy resin (EP), a lignin-based flame retardant was prepared. Focusing on the lignin-based flame retardant, this paper investigates its pyrolysis behavior and kinetics via a thermogravimetric analyzer coupled with Fourier transform infrared spectrometry (TG–FTIR). Based on the FTIR result, which showed a peak at 1222 cm−1, it was assigned a syringyl structure. Its absorption peak intensity was enhanced and this meant that the phenolization of the lignin was successful. Thermogravimetry/derivative thermogravimetry (TG/DTG) results showed that the carbon residues of F-lignin and F-lignin@APP were reduced to 33.5% and 37.5%, respectively. In addition, the maximum decomposition rate of F-lignin@APP20/EP is 11.8%/min, which is 8%/min and 4.7%/min lower than for EP and Al-lignin, respectively. The char residue of F-lignin@APP20/EP is 32.5%, which is much higher than for EP. Lower decomposition rate and higher char residue indicate the improvement of thermal stability of EP by F-lignin@APP. Moreover, the kinetics of Al-lignin20/EP and F-lignin@APP20/EP were conducted by two kinetic methods: Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS). It was concluded that the pyrolysis process of Al-lignin 20/EP and F-lignin@APP 20/EP could be divided into three stages, while the value and growth rate of the activation energy of F-lignin@APP 20/EP were much higher than that of Al-lignin 20/EP in stage III.

Decision support for solution of straw waste into asphalt material based on TG–FTIR

To clarify the effect and mechanism of straw waste on the properties of asphalt materials, two types of modified asphalt were prepared by using straw powder (SP) and incineration ash (IA). The impact of SP and IA on the physical properties of asphalt was studied. The microscopic morphology characteristics and chemical composition of modified asphalt were analysed and investigated using a focused ion beam scanning electron microscope and an energy-dispersive X-ray spectrometer. Finally, the thermal properties and molecular structure variation of modified asphalt were characterised by a thermogravimetric analyser coupled with a Fourier transform infrared spectrometer. The results indicate that IA has a greater potential in enhancing and improving the physical and thermal properties of asphalt than SP. The incinerating process could promote the fusion between SP and asphalt, which mitigates the negative effect on low-temperature deformation of asphalt. IA could reduce the weight loss of asphalt, obviously preventing its combustion process. The addition of IA leads to the variation of absorbance intensity of asphalt, which suggests the potential of IA on improving the thermal stability of asphalt materials.

Influence of coal ash on the characteristics of corn straw pyrolysis products

To discern influence of inorganic substances in coal on the co-utilization of coal and biomass, coal ash (CA) was added to biomass for pyrolysis. TG–FTIR and fixed bed reactor were used for pyrolysis of corn straw (CS) with CA. XRF and XRD were used to detect the reactants and products components, respectively. At constant heating rate. CA slightly promoted char and gaseous products formation. In the fixed bed reactor, the effect varied with temperature and CA addition ratio. The char and gas yields were changed due to the Si, Al, and other inorganic substances in CA. CS/CA = 1 had the greatest influence on char. Gas yield were reduced at 500–700 °C, but increased at 800 °C with a small proportion of CA. When CA was 1/10 of CS at 800 °C, the gas yield increased by 9.3%, and CH4, CO, and H2 increased by 26.1%, 8.4%, and 37.7%, respectively.

Thermal study, identification of intermediate solid products and evolved gas analysis (EGA) during pyrolysis and oxidative decomposition of sodium complex of quercetin-5′-sulfonic acid (Na-5′-QSA)

The sodium 3,3′,4′,5,7-pentahydroxyflavon-5′-sulfonate tetrahydrate (sodium quercetin-5′-sulfonate; Na-5′-QSA) was fully characterized by a combined TG/DTG–DSC method in synthetic air and helium atmosphere, evolved gas analysis (EGA) by coupled TG–MS–FTIR technique as well as temperature controlled X-ray diffraction.The detailed thermal and diffraction studies provided previously unreported information on the thermal behavior of Na-5′-QSA. Intermediate solid products formed during thermal degradation in air and helium atmosphere were identified. It was proved that decomposition processes are multistage in both atmospheres and there is no significant difference in thermal behavior of Na-5′-QSA in oxidative and inert conditions up to 260 °C. The model of the crystal structure was determined for one of the components of an intermediate solid product which was crystalline anhydrous quercetin. The TG–FTIR–MS technique allowed the identification of the gaseous products evolving during oxidative decomposition and pyrolysis of the analyzed compound. Main gaseous products released during the thermal decomposition were water vapors, carbon dioxide, sulfur dioxide, carbonyl sulfide, carbon monoxide (in air and helium atmosphere) and the fragments of aromatic compounds formed additionally in helium atmosphere.

Co-pyrolysis of sewage sludge and rice husk by TG–FTIR–MS: Pyrolysis behavior, kinetics, and condensable/non-condensable gases characteristics

In this study, pyrolysis behavior, kinetics, and condensable/non-condensable gases characteristics during co-pyrolysis of sewage sludge (SS) and rice husk (RH) were evaluated using Thermogravimetric–Fourier transform infrared spectrometry–Mass spectrometry (TG–FTIR–MS). The mass loss was divided into two stages: the main devolatilization and the continuous slight decomposition of macromolecular substances. The pyrolysis behavior was improved during co-pyrolysis, and the interaction between SS and RH showed synergistic and inhibitive effects. The lowest average activation energy was obtained at 30% RH blending; the Diffusion 3D (Zhrualev–Lesokin–Tempelmen) reaction model can fit the pyrolysis process using the Coats–Redfern method. The functional groups and condensable/non-condensable gases (O-H, C=O, C-O, C-H benzene skeleton, CO, CO 2 ) were detected by FTIR, revealing the synergistic effect on the evolution of condensable/non-condensable gases in the promotion of C-O, C=O and CO 2 release in blends. The condensable and non-condensable products were detected via MS (including aliphatic and aromatic hydrocarbons, CO 2 , NOx and SOx). The results showed that CO 2 was the main gaseous product and confirmed an enhancement of the CO 2 release during co-pyrolysis. The release of both hydrocarbons (C 2 H 6 , C 4 H 7 + , C 4 H 8 ) and pollutants (SO, SO 2 and toluene) were significantly increased when dealing with pyrolysing the feedstock blend. • Co-pyrolysis of sewage sludge and rice husk was studied by TG-FTIR-MS. • Blending rice husk improved the pyrolysis behavior of blends. • The lowest average activation energy was obtained at 30% RH blending. • Synergistic effect on the volatiles appeared during co-pyrolysis.

Complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) with ligand formed by condensation reaction of isatin with glutamic acid

The complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) with ligand (H2L=C13H12N2O5) formed by condensation reaction of isatin and glutamic acid were synthesized. Their physico-chemical properties were characterized using elemental analysis, XRF, XRD, FTIR, TG–DSC and TG–FTIR methods and magnetic measurements (Gouy’s and SQUID-VSM methods). The complexes were obtained in crystalline forms (monoclinic or triclinic) with the formulae: M(LH)2·nH2O for Mn(II), Ni(II) and Zn(II) and ML·nH2O for Co(II) and Cu(II), where LH=C13H11N2O5–, L-=C13H10N2O52–, n = 1 for Mn(II), Cu(II) and Zn(II), n = 2 for Co(II) and n = 3 for Ni(II). In air at 293–1173 K they decompose in three steps forming finally the oxides of the appropriate metals. The gaseous decomposition products were identified as: H2O, CO2, CO, hydrocarbons and N2O. The magnetic moment values for complexes (except Zn(II) complex) show their paramagnetic properties with the ferro- and antiferromagnetic interactions between central ions. The compounds of Mn(II) and Co(II) are high spin complexes with weak ligand field. In Co(II) and Cu(II) complexes two carboxylate groups take part in the metal ion coordination while in those of Mn(II), Ni(II) and Zn(II) only one carboxylate anion coordinates to central ion.

Unusual Atmospheric Water Trapping and Water Induced Reversible Restacking of 2D Gallium Sulfide Layers in NaGaS2 Formed by Supertetrahedral Building Unit

Two new ternary materials NaGaS2 (1) and the Fe-doped phase of NaGaS2, NaFe0.135Ga0.865S2 (2), have been synthesized by employing polysulfide flux. Single crystal XRD analyses of 1 and 2 show that the structure is built up of adamantane-like Ga4S10 super tetrahedral fundamental building units. These admantane-like units are connected through their corners to form [GaS2]∞– layers that are stacked one over the other with Na ions residing in between the layers to balance the charge. Both the materials have the remarkable ability to absorb atmospheric water molecules and moisture from undried solvents as verified by TG analysis and FT-IR and XPS studies. The process of water absorption leads to stable distinct material NaGaS2·∼H2O (1·H2O) and NaFe0.135Ga0.865S2·∼H2O (2·H2O) with restacked layers different from original crystal structure. This structural transformation is reversible as the transformed structures 1·H2O and 2·H2O can be returned to their original structures 1 and 2, respectively, upon heating. DFT calculation study reveals that a spontaneous exergonic hydration reaction takes place as outlined in NaGaS2 + H2O → NaGaS2·H2O with the energy release, ΔE of −73.9 kJ mol–1. DFT calculation predicts an increase in the unit cell parameters of b and c directions and shrinkage along the a direction of hydrated phase 1·H2O with an overall volume increase of 36.6%. Structural transformation affects their physical properties as the pristine compound 1 possess Na+ ion conductivity of 2.88 × 10–7 S cm–1 at 22 °C, whereas the hydrated compound 1·H2O displays ∼40 times increased ion conductivity of 1.25 × 10–5 S cm–1 at the same temperature. DRS studies show very similar optical band gaps of ∼4 eV for compounds 1 and 1·H2O, respectively, in reasonable agreement with the DFT­(HSE) band gap estimation but more than 1 eV above the DFT­(PBE)-predicted band gaps of ∼2.4 eV. A sorption study indicates selective adsorption of water over MeOH, EtOH, and CH3CN with a maximum water uptake of 2.6 H2O per formula unit at P/P0 = 0.9. A Karl Fischer titration study shows that NaGaS2 (1) is certainly capable of adsorbing water from wet methanol and can be useful as a fast desiccating agent.

Study on the pyrolysis properties of corn straw by TG–FTIR and TG–GC/MS

Corn straw, an agricultural waste with huge yields, can be thermochemically treated to promote its comprehensive utilization. Compared with traditional methods, thermogravimetry coupled with Fourier transform infrared spectroscopy (TG–FTIR) and thermogravimetry coupled with gas chromatography–mass spectrometry (TG–GC/MS) can be used to analyze more clearly the pyrolysis of corn straw. In this study, the distributed activation energy model was used to analyze the pyrolysis kinetics in order to elucidate the pyrolysis process. The distributed activation energy of corn straw changed from 93.39 to 186.57 kJ mol−1 at the conversion rates from 0.1 to 0.9 with a high correlation coefficient. The evolution of volatile products from corn straw pyrolysis was discussed by TG–FTIR and TG–GC/MS. Results showed that CO2, CH4, CO, H2O, and carbonyls were produced below 337 °C and reached their peak values at the maximum mass loss rate of corn straw corresponding to the pyrolysis temperature of 337 °C. Carbonyl compounds were mainly composed of C4–C5, which come from the pyrolysis of cellulose and hemicellulose. At high pyrolysis temperatures, the organic species of furans, phenols, ketones, and aldehydes increased because of the fracture and isomerization of cellulose and hemicellulose. Meanwhile, Benzene and long-chain alkanes have been found due to the removal of oxygen-containing functional groups and the rupture of benzene ring in lignin structure.

Halogen-free and phosphorus-free flame-retarded polycarbonate using cyclic polyphenylsilsesquioxanes

Organic–inorganic hybrid macrocyclic compounds, polyphenylsilsesquioxanes (cyc-PPSQ), have been synthesized through hydrolysis and condensation reactions of phenyl trichlorosilane. PC/cyc-PPSQ flame retardant materials were obtained by melt blending cyc-PPSQ and PC using a twin-screw extruder. The combustion and thermal decomposition behavior of PC/cyc-PPSQ composites were studied using UL-94, LOI, CONE, TG–FTIR and Py–GC/MS, which showed that the presence of cyc-PPSQ could improve flame retardancy and reduce the heat release and smoke release during combustion of PC. Incorporation of 2 wt% cyc-PPSQ produced a PC/cyc-PPSQ-2 composite which displayed LOI 37.5% and UL-94 V-0 (1.6 mm). The presence of cyc-PPSQ not only improved the flame retardancy of PC, but also did not diminish the glass transition temperature, good mechanical properties and transparency of PC. These results combined with those from TG–FTIR analysis suggest that cyc-PPSQ can promote the initial thermal induced chain-breaking reaction of PC, promote the cross-linking and charring of PC, and facilitate the formation of a dense carbon layer and external SiO2 inorganic barrier layer during combustion. Results from Py–GC/MS indicate that the presence of cyc-PPSQ promotes the generation of phenolic compounds when the composites are pyrolyzed at high temperature.

Preparation of biochar from food waste digestate: Pyrolysis behavior and product properties

Solid digestate generated in the anaerobic digestion of food wastes was evaluated as a potential feedstock for biochar preparation by pyrolysis in this study. To understand the pyrolysis mechanism, thermogravimetric experiments were firstly implemented at different heating rates, then apparent activation energy during pyrolysis was calculated by using the Starink isoconversional method, ranging from 144.64 kJ/mol to 293.36 kJ/mol with the conversion increasing in the region from 0.10 to 0.90. The evolutions of released volatiles were accurately and continuously analyzed by TG–FTIR–MS. Results show that dehydration and CO2 emission were the main reasons for mass loss, and light hydrocarbons were released in step II of the pyrolysis process. Elemental compositions and surface properties of the biochars obtained at different pyrolysis temperatures were characterized by EA, XRF and BET. The obtained results provide an alternative strategy for disposing waste generated in anaerobic digestion of food waste.

Fabrication of a novel acrylate polymer bearing chalcone and amide groups and investigation of its thermal and isoconversional kinetic analysis

The aim of the article was to examine the thermal degradation, thermal decomposition kinetics and dielectric behavior of novel poly(APHP-Am–Ac). For this purpose, the novel monomer, 4-(3-(4-acetamidophenyl)-3-oxoprop-1-en-1-yl)phenyl acrylate (APHP-Am–Ac), was synthesized from 1-(4-aminophenyl)-3-(4-hydroxyphenyl) prop-2-en-1-one (APHP) and acetic anhydride reaction. The homopolymer P(APHP-Am–Ac) was prepared by free radical polymerization within dimethylformamide at 80 °C. The presence of rigid and bulky chalcone units in polymer side chains significantly improved the solubility of polyamides, giving them an amorphous nature and good thermal stability. The structural characterization of homopolymer was accomplished using FT-IR and NMR techniques. The thermal stability and degradation features of homopolymer have been performed by using TG analysis and FT-IR during partial degradation at different temperatures. The glass transition temperature of homopolymer was determined by DSC analysis. For thermal decomposition kinetics of poly(APHP-Am–Ac), Flynn–Wall–Ozawa and Kissinger methods were applied to thermogravimetric curves and apparent activation energies (Ea) calculated from these two methods. According to FWO, the activation energy (Ea) of the first step and the second step was found as: 157.78 kJ mol−1 and 151.81 kJ mol−1, respectively. For Kissinger’s model, Ea was calculated as 154.3 kJ mol−1 and 142.83 kJ mol−1, respectively. The dielectric and conductivity measurements of homopolymer were investigated by impedance analyzer technique in a range of 10 Hz–20 kHz frequency at different temperatures (from 25 to 120 °C). The results have been plotted as a function of frequency and temperatures. The values increased significantly with temperature.

Thermal behavior and smoke characteristics of glass/epoxy laminate and its foam core sandwich composite

Thermal behavior and smoke characteristics of glass/epoxy laminate and its foam core sandwich composite were comprehensively investigated using thermogravimetric analysis, TG–FTIR analysis, smoke density test and cone calorimeter test. The thermal decomposition, thermal interpretation of gas release, smoke density, smoke release, carbon monoxide and carbon dioxide productions were analyzed and compared for glass/epoxy laminate and its foam core sandwich composite. Their kinetic and thermodynamic models were obtained, and the apparent activation energy, pre-exponential factor and thermodynamic parameters were determined correspondingly. The results show that there are significant differences in the thermal behavior and smoke characteristics between these two composites. Compared with glass/epoxy laminate, foam core sandwich composite demonstrates a higher propensity of pyrolysis and combustions and greater hazards to life and property.

Effect of aluminum diethylphosphinate on flame retardant and thermal properties of rigid polyurethane foam composites

Rigid polyurethane foam/aluminum diethylphosphinate (RUPF/ADP) composites were prepared by one-step water-blown method. Furthermore, scanning electron microscope (SEM), thermal conductivity meter, thermogravimetric analysis (TGA), limiting oxygen index, Underwriters Laboratories vertical burning test (UL-94) and microsacle combustion calorimetry were applied to investigate thermal conductivity, thermal stability, flame retardancy and combustion behavior of RPUF/ADP composites. Thermogravimetric analysis–Fourier transform infrared spectroscopy (TG–FTIR) was introduced to investigate gaseous products in degradation process of RPUF/ADP composites, while SEM and X-ray photoelectron spectroscopy were used to research char residue of the composites. It was confirmed that RPUF/ADP composites presented well cell structure with density of 53.1–59.0 kg m−3 and thermal conductivity of 0.0425–0.0468 W m−1 K−1, indicating excellent insulation performance of the composites. Flame retardant test showed that ADP significantly enhanced flame retardancy of RPUF/ADP composites, RPUF/ADP30 passed UL-94 V-1 rating with LOI of 23.0 vol%. MCC test showed that ADP could significantly decrease peak of heat release rate (PHPR) of RPUF/ADP composites. PHPR value of RPUF/ADP20 was decreased to 158 W g−1, which was 21.8% reduced compared with that of pure RPUF. TG–FTIR test revealed that the addition of ADP promoted the release of CO2, hydrocarbons and isocyanate compound in first-step degradation of RPUF matrix while inhibited the release of CO in second step degradation. Char residue analysis showed that the addition of ADP promoted polyurethane molecular chain to form aromatic and aromatic heterocyclic structure, enhancing strength and compactness of the char. This work associated a gas–solid flame retardancy mechanism with the incorporation of ADP, which presented an effective strategy for preparation of flame retardant RPUF composites.

Study of the thermal behavior in oxidative and pyrolysis conditions of some transition metals complexes with Lornoxicam as ligand using the techniques: TG-DSC, DSC, HSM and EGA (TG-FTIR and HSM-MS)

Lornoxicam metal complexes [M(Lor)2(OH2)2]∙nH2O, where M represents the bivalent transition metals (Mn(II) to Zn(II)), Lor is Lornoxicam ligand and n = 2.0 or 2.5 were synthesized. The compounds were characterized by elemental analysis (EA), powder X-ray diffraction (PXRD), infrared spectroscopy (FTIR), simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC) under oxidizing and pyrolysis conditions, differential scanning calorimetry (DSC), hot-stage microscopy (HSM) and evolved gas analysis (EGA) by coupled hot-stage microscopy (HSM-MS) and Fourier transform infrared (TG–FTIR). Regardless of the atmosphere, the thermal stability and thermal behavior up to the first two mass loss steps of the anhydrous compound were similar, only differing significantly in the last steps. The main gaseous products released were H2O (dehydration), SO2, CO, CO2, COS, HCN, HNCO, Methyl Isocyanate, and Ethyl Isocyanate. In addition, FTIR data suggest that pyridyl and carboxyl groups are the coordination sites for metal ions and confirm the presence of differing bounded waters.