Pyrolysis of flame retardants and fire protected polymers

The simultaneously working combination of thermal analysis and mass spectrometry (TA/MS) is a very useful method for studying the degradation process of polymeric materials during thermal treatment [1–7]. Beside the thermal effects, as recorded from thermogravimetry (TG) or differential thermal analysis (DTA) the evolved degradation products can be determined and identified by the on - line coupled mass spectrometer. Additional their temperature depending abundance can be registrated. Combustion of polymers in horizontal (BIS) or vertical (VCI) furnaces and subsequent off line high resolution GC/MS analysis of pyrolysis products is suitable for the simulation of burning processes     

Investigation of the thermal degradation process of polystyrene brominated on the ring

The results of investigation of the degradation process of polystyrene brominated on the ring via an ionic route have been presented. Using thermogravimetric (TG) and differential thermal analysis (DTA) methods, the course of degradation of polymer samples with different bromine content has been described. Introducing of bromine on the aromatic ring influenced the initial decomposition temperature (IDT) and the temperature corresponding to the maximum of decomposition rate (T _m). The samples have been pyrolyzed at 300°C and some pyrolysis products were identified by means of gas chromatography/mass spectrometry. Finally, the possible mechanism of degradation was presented.     

Thermogravimetric Study of Carbonization Processes for Industrial Porous Co-polymers of Spherical Granules

The industrial porous co-polymers and resins in the form of spherical granules include three main matrices which serve as the basis of the large-scale production of ion-exchange materials: styrene/divinylbenzene, vinylpyridine/divinylbenzene and acrylonitrile/divinylbenzene. Complex thermal methods (TG, DTG and DTA) were used to study the carbonization processes of various industrial products utilized as starting materials for the preparation of synthetic active carbons. The DTG results, the thermal effects observed during the programmed heating of samples, and the mass-spectrometric and IR-spectroscopic data up to 800°C provided a picture of a multi-stage carbonization process. This includes the removal of moisture from the polymer matrices, the primary cross-linking of the chains, their aromatization and condensation due to the cross-linking of polynuclear structures, and the removal of ‘excess carbon’ as simple molecules and free radicals of hydrocarbon type. The results promoted the choice of the optimal regimes in which to carryout the isothermal pyrolysis of various polymer matrices and preliminary chemical modifications to increase the yields on carbon and to prepare synthetic active carbons such as those of SCN, SCAN and SCS types. General schemes were proposed for the chemical reactions accompanying the carbonization process for these polymer matrices. This revised version was published online in August 2006 with corrections to the Cover Date.     

The application of thermal analysis to the combustion of cellulose

It is shown that the use of differential thermal analysis (DTA) to follow the pyrolysis of cellulose in air products two and sometimes three exothermic peaks. The first peak is associated with the combustion of volatile material, released in the degradation process, the second is caused by the glowing combustion of the carbonaceous residue, and the final exotherm is probably due to the combustion of product gases.The thermogravimetric analysis (TG) data in air show a preliminary loss of water followed by a mass loss of about 85% due to the production of the combustible volatiles. This second step appears identical to the degradation process in nitrogen, but in air the degradation products ignite to produce the first exothermic peak on the DTA. The glowing combustion DTA peak is associated with a further mass loss of about 15% on the TG plot. The use of a thermomechanical analyser shows that a small shrinkage of 3% occurs between 45 and 110°C, with the major collapse taking place between 300 and 370°C. There is, however, an expansion of 10% between 370 and 405°C, believed to be due to a crosslinking reaction.     

高分子固体电解质LiNO_3-LiOOCCH_3/聚丙烯酸锂的合成与性能研究

以丙烯酸和氢氧化锂为原料用反相乳液聚合法合成聚丙烯酸锂 (PAALi) ,将其熔于低共熔盐 (一定比例的LiNO3 LiOOCCH3混合物 )中得到新型高分子固体电解质 (SPE) ,用XRD、IR、DTA、TG DTG等技术进行了表征 ,讨论了影响合成PAALi工艺及新型固体电解质电阻率的主要因素 ,在LiNO3 LiOOCCH3摩尔比为 1∶1时 ,将其按质量百分比 80∶2 0与聚丙烯酸锂混合均匀并熔融 ,得到的电解质其室温离子电导率可达 2× 10 - 5S·cm- 1 ,大量低共熔盐的加入可明显提高SPE的离子导电率 .XRD、DTA及TG DTG结果表明低共熔盐与聚丙烯酸锂形成了新的配合物     

Thermal behaviour of lignins extracted from different raw materials

The thermal degradation of lignins extracted from bagasse, rice straw, corn stalk and cotton stalk, have been investigated using the techniques of thermogravimetric analysis (TG) and differential thermal analysis (DTA), between room temperature and 600°C. The actual pyrolysis of all samples starts above 200°C and is slow. The results calculated from TG curves indicated that the activation energy, Efor thermal degradation for different lignins lies in the range 7.949–8.087 kJ mol^?1. The DTA of all studied lignins showed an endothermic tendency around 100°C. In the active pyrolysis temperature range, thermal degradation occurred via two exothermic process at about 320 and 480°C, and a large endothermic pyrolysis region between 375 and 450°C. The first exothermic peak represents the main oxidation and decomposition reaction, the endothermic effect represents completion of the decomposition and the final exothermic peak represents charring.     

Analysis of the products of thermal decomposition of an aromatic polyamide fabric

The thermal degradation of an aromatic polyamide was studied under conditions of pyrolysis and oxidative degradation at 550°C and of flaming combustion. Techniques described elsewhere were used to determine the volatile compounds quantitatively by gas chromatography-mass spectrometry (GC–MS). The condensible material and the solid residue were characterized by infrared spectroscopy and MS, and in pyrolysis experiments 28 compounds were identified (CO, CO₂, H₂O, and C₆H₅CN were the primary products). Collectively, these compounds accounted for 79% of the sample weight loss. The remaining 21% was a condensible material that contained at least 17 compounds; the two major components were 1,3-dicyanobenzene and 3-cyanobenzoic acid. Most of the nitrogen content of the polymer remained as involatile residue. This study was sufficiently detailed to obtain a mass balance between the composition of the original polymer and the sum of the observed pyrolysis products. The major products observed in pyrolysis experiments supported a mechanism that involved the cleavage of an aromatic-NH bond and the loss of H₂O to form aromatic nitriles. Hydrolysis of the amide linkage, followed by decarboxylation of the product acid, accounted for the high concentrations of CO₂ observed. Oxidative degradation at 450°C yielded ten identifiable compounds and an additional 19 volatile compounds were formed at 550°C. The condensible fraction, which contained at least 20 compounds, was similar in composition to the fraction collected from the pyrolysis experiments. The sum of the carbon content from the two major volatile products of oxidative degradation (CO and CO₂) and from the solid residue quantitatively accounted for the carbon content in the original sample. Flaming combustion studies revealed a markedly different product distribution than was observed under nonflaming conditions, especially in regard to the higher-molecular-weight species.     

A degradation study of waterborne polyurethane based on TDI

The thermal degradation of synthetic waterborne polyurethane (PU) based on toluenediisocyanate (TDI) was investigated by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and thermogravimetry (TG). The degradation profiles of cast films obtained from dispersions were evaluated. More than 20 characteristic volatile pyrolyzates reflecting the structure and pyrolysis mechanisms of the polymer have been identified by on-line MS. The synthesized products of polyurethane were pyrolyzed at 350, 450, 550, 650 and 750 °C respectively, and the analysis results revealed that the pyrolyzates distribution of the polyurethane depends strongly on the pyrolysis temperature. The aqueous polyurethane thermogravimetric measurements were used to study the kinetics of thermal degradation.     

Pyrolysis study of sol-gel derived zirconia by TG-GC-MS

Summary A homogeneous ZrO₂ gel was obtained by hydrolysis-condensation of zirconium(IV) n-propoxide previously reacted with acetic acid. Dried zirconia powders were characterized by Fourier transformed infra-red (FTIR) and X-ray diffraction (XRD) analyses. Thermogravimetric (TG) and differential thermal analysis (DTA) coupled with mass spectrometric (MS) and gas chromatographic (GC) measurements were carried out in order to identify and quantify the organic products released during the ZrO₂ gel pyrolysis. The TG-MS semi-quantitative analysis of the main released species allowed to describe the chemical rearrangement occurring in the solid during heating and to determine the chemical composition of the initial gel.     

废弃印刷电路板材料裂解产物的高分辨裂解气相色谱-质谱分析

采用高分辨裂解气相色谱-质谱法(PyGC-MS)分析了FR-4型印刷电路板粉末样品的裂解产物。在氦气氛围中,分别在350,450,550,650和750 ℃下对印刷电路板粉末样品进行热裂解,并通过毛细管气相色谱-质谱对裂解产物进行分析,研究了不同裂解温度下裂解产物分布以及主要裂解产物的产率与裂解温度的关系,根据热分解产物的组成,探讨了热分解反应机理。     

30 years of research in thermal analysis and calorimetry

The research in thermal analysis and calorimetry, conducted by the author over the period 1964 to 1993, is summarised and concisely reviewed. The major investigations have focussed on thermal analysis studies of coordination compounds, particularly the metal dithiocarbamate complexes. A significant solution calorimetric study of some metal dithiocarbamate complexes has also been undertaken. DSC has been applied to determine the sublimation enthalpies of many metal dithiocarbamate and metal pentane-2,4-dionate complexes and solution calorimetry has been applied to study the thermochemistry of the latter group of complexes. Thermal analysis investigations of several inorganic molten salt systems have been initiated. Thermometric titrimetry has been applied to study metal-macrocyclic ligand systems in aqueous media and particularly those systems of environmental significance. Temperature calibration standards for TMA have been proposed and TMA has been applied to study the mechanical properties of several common inorganic compounds. DTA has been applied to study a wide variety of phenols and has subsequently been applied as an analytical technique to determine the components of solid state phenol mixtures. Thermometric titrimetry has been applied to determine the phenolic content of wines. A comprehensive thermal analysis study of Australian brown coal has been undertaken, involving the DSC determination of coal specific energy, a TG/DTA study of the coal pyrolysis and combustion processes and a TG/DTA and EGA study of the cation catalytic effect on the coal pyrolysis process. Thermal analysis and calorimetric techniques have been extensively publicised and promoted by the publication of specialist reviews, the presentation of symposia review papers and the oral presentation of short courses, particularly in the SE Asian region. This review essentially reveals the diversity of possible application of thermal analysis and calorimetric techniques and the primary significance of thermodynamic data in the fundamental rationalisation of chemical phenomena.     

Effect of chlorinated fire-retardant additives on the thermal degradation of polypropylene

Modifications in the thermal degradation mechanism of polypropylene caused by interactions between the degrading polymer, a chloroparaffin and bismuth carbonate (typical fire retardant additives) are studied.Preliminary TVA and pyrolysis-GLC results show that volatilisation of the polymer occurs at lower temperatures with production of a larger proportion of higher boiling chain fragments in the mixture than in the pure polymer.The products of a strongly exothermal reaction occurring when the two additives are heated together, as shown by DTA and TG, could play an important role in modifying the thermal degradation behaviour of polypropylene in the mixture.     

Combining thermal analysis with other techniques to monitor the decomposition of poly(m-phenylene isophthalamide)

The pyrolysis behaviour of Nomex, poly(m-phenylene isophthalamide) fibres under argon has been investigated up to a temperature of 1173 K with different methods to get direct information on the progressive changes taking place in the solid material and its carbon fibre residues. The main stages of the pyrolytic degradation of the fibres were determined by thermal analysis (TG and DTA) and their chemical and morphological evolution through the different steps was subsequently followed by Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM) measurements, respectively, on samples treated to various temperatures. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermal analysis of some pharmaceutically relevant systems obtained by SOL-gel technique

Thermal analysis has been performed of xerogels obtained by encapsulation of sodium thiosulfate (systems I and II), glycerol with I₂/KI (system III) and urea with I₂/KI (system IV) in silica gel. DTA, TG and DTG of the xerogels with thiosulfate differed markedly depending on the thiosulfate content. At the 22% thiosulfate content in the original silicic acid solution used for the preparation of the xerogel, a single exothermic peak appears in the DTA trace assignable to the combustion of elemental sulfur derived either from the reaction between silicic acid and the thiosulfate or from the thermal degradation of the latter. When the thiosulfate content in the original solution is raised up to 60%, the peak is split into two symmetrical components, one (at 553 K) attributable to combustion of the more finely dispersed sulfur and the other (at 703 K) to sulfur particles of coarser morphology. The former is likely to be formed by chemical interaction of the components of original solution and the latter is due to thermal degradation of residual thiosulfate. The main features of a DTA, TG and DTG obtained from xerogel III are exothermic events recorded in the DTA trace suggesting that after the loss of iodine, thermal degradation of glycerol takes place with the onset at 523 K leaving a combustible solid. Under these conditions, glycerol alone distilled out with no evidence for degradation. A derivatogram of xerogel IV is characterized by initial sublimation/evaporation of urea and iodine followed by partial condensation of urea to afford biuret and eventually cyanuric acid. This revised version was published online in August 2006 with corrections to the Cover Date.     

Thermal degradation of poly((E,E)-[6.2]paracyclophane-1,5-diene)

Thermal degradation of poly((E,E)-[6.2]paracyclophane-1,5-diene) is studied in inert and oxidative environments by using thermogravimetric analysis, pyrolysis GC/MS, pyrolysis GC/FT-IR, and variable temperature-diffuse reflectance infrared spectroscopy (VT-DRIFTS). Thermal degradation in helium begins by depolymerization yielding a volatile product capable of abstracting hydrogens from the polymer residue. Multiple hydrogen abstractions result in a variety of volatile species containing benzyl-benzyl bonds. In the presence of oxygen, polymer decomposition is dictated by reactions of peroxy and hydroperoxy radicals. At low temperatures, oxygenated species are the primary products. At higher temperatures, increased unsaturation is detected in the polymer residue. In both inert and oxidative environments, the strain associated with alignment of paracyclophane aromatic rings is lost during the initial stages of thermal degradation. © 1992 John Wiley & Sons, Inc.     

Characterization of herbal medicine with different particle sizes using pyrolysis GC/MS, SEM, and thermal techniques

Analytical techniques have been used to characterize compounds from herbal medicine, its products and extracts. The objective of this study was to characterize a variety of particle sizes of Erythrina velutina Willd powder. The samples used in the study were named MUF01 (710 μm), MUF03 (180 μm) and MUF05 (75 μm). The techniques employed were scanning electron microscopy (SEM), thermal analysis such as thermogravimetry (TG) and differential thermal analysis (DTA) together with pyrolysis coupled to gas chromatography/mass spectrometry (Pyr-GC/MS). SEM enabled us to detect the existence of divergences from the expected results from the granulometry process. Thermal analytical techniques (TG and DTA) showed the thermal decomposition profile, corresponding to physical and chemical phenomena. The chromatographic data relative to the peak area of the compounds analyzed evidenced quantitative differences in the chemical compositions of the samples MUF01, MUF03, and MUF05 at 300, 450 and 600 °C. Neophytadiene 2,6,10-trimethyl, 14 and 3-eicosyne were identified by Pyr-GC/MS at 300, 450 and 600 °C, and it classified the samples according the peak area values, which were MUF05 > MUF03 > MUF01. SEM, DTA and TG confirmed this through particle size uniformity, heat flow, and mass loss, respectively.     

马瑞原油在空气和氮气中的热解-氧化性能

低温氧化是注空气采油及原位燃烧采油技术中的重要化学反应,为深入认识原油在有氧环境下复杂热反应过程中的低温氧化特性,我们采用热重/差热分析法(TG/DTA)研究了线性升温和等温条件下马瑞(Merey)原油的热反应行为。 结果表明,Merey原油在空气及线性升温条件下的受热过程分4个阶段:气化段、低温氧化段、热解段和高温氧化段;相邻阶段的物理、化学主导过程的重叠增加了分析原油热反应特征的难度。 升温速率提高,气化段和低温氧化段的终止温度不变;热解段和高温氧化段的终止温度以及热解段的峰温随升温速率的增加而升高。 N₂气与空气下Merey原油的热重/微分热重(TG/DTG)数据对比表明,升温速率越高,空气下的高温氧化段与热解段重叠程度越大,这有利于燃烧但会降低原油采收率。 空气下等温时的TG/DTA结果表明随升温速率增加,升温至300 ℃时的失重率降低,不利于原油轻组分的气化。 反应温度越高,气化过程时间越长,失重分数越大。 Merey原油在低于300℃时低温氧化反应不是主导反应。     

Thermal and burning properties of wood flour-poly(vinyl chloride) composite

The present study deals with the effects of wood flour on thermal and burning properties of wood flour-poly(vinyl chloride) composites (WF-PVC) using thermogravimetric (TG), cone calorimetry (CONE), and pyrolysis?Cgas chromatography/mass spectrometry (Py?CGC/MS). TG tests show that an interaction occurred between wood flour and PVC during the thermal degradation of WF-PVC. Wood flour decreased the temperature of onset of decomposition of PVC. However, the char formation could be increased by adding wood flour to PVC. CONE test indicates that wood flour had positive effects on heat release and smoke emission of PVC. Comparing with PVC, WF-PVC reduced average heat release rate and the peak HRR by about 14 and 28%, respectively; smoke production rate was also decreased. The degradation mechanism was studied by Py?CGC/MS. The results show that the volatile pyrolysis products of WF-PVC are very different from PVC. The yields of HCl and aromatic compounds decreased dramatically, and the aliphatic compounds increased by the incorporation of WF.     

An investigation about the solid state thermal degradation of acetylsalicylic acid: polymer formation

An investigation about the thermal degradation of acetylsalicylic acid (ASA) is performed. It is verified that the thermal degradation of ASA produces not only salicylic acid (SA) and acetic acid (AA) as products but also an ASA polymer, which is transparent and solid. And also verified that the temperature in which the polymer is obtained influences its physical consistence (solid or semi-solid). Furthermore, the ASA polymer is very stable from a thermic point of view, as verified by TG and DSC analysis. X-ray diffraction patterns obtained for the ASA polymer show that it exhibits a low crystallinity.     

Pyrolysis of olive residue/low density polyethylene mixture: Part I Thermogravimetric kinetics

This paper demonstrates the thermal pyrolysis of olive residue, low density polyethylene (LDPE) and olive residue/LDPE mixture in an inert atmosphere of N2 using thermogravimetric analysis (TGA). Measurements were carried out in the temperature range 300K~973K at heating rates of 2K/min, 10K/min, 20K/min and 50K/min. Based on the results obtained, three temperature regimes were selected for studying the nonisothermal kinetics of olive residue/LDPE mixture. The first two were dominated by the olive residue pyrolysis, while the third was linked to the LDPE pyrolysis, which occurred at much higher temperatures. Discrepancies between the experimental and calculated TG/DTG profiles were considered as a measurement of the extent of interactions occurring on copyrolysis. The maximum degradation temperatures of each component in the mixture were higher than those the individual components; thus an increase in thermal stability was expected. The kinetic parameters associated with thermal degradation were determined using Friedman isoconversional method.