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J. Mass Spectrom. Soc. Jpn., 46(4), 259-274 (in Japanese), 1998
Mechanisms of pyrolysis of cellulose which have been presented are reviewed in terms of pathways of the reaction, production of levoglucosan, carbonization and pyrolysis of levoglucosan, and kinetics. In addition measurement with machines are discussed in relation to the pyrolysis. In the section of reaction path ways five models given in diagrams are introduced and indicated lack of clear chemical definition of them, and in the levoglucosan formation six principal models are briefly described, and a proposal of an ion mechanism against a radical mechanism, and different interpretations of effects of fine structures on the reaction and the chain length are pointed out to make important controversial points. In the third section changes in residue structure through carbonization are discussed, and courses of levoglucosan pyrolysis full of variety are shown and significance of researches on the pyrolysis in air is emphasized from viewpoint of fire science. In the fifth section an enormous number of kinetic data presented with different orders of reaction are shown and a kinetics is systematically developed to explain the different reaction orders. In the sixth section, the dependency of data on individual instruments are revealed in the measurement with instruments problems involved in analytical pyrolysis. Understanding of the implication and reasonable choice of the data is shown to be important.
J. Mass Spectrom. Soc. Jpn., 46(4), 275-282 (in Japanese), 1998
A few examples of application of evolved gas analysis by mass spectrometry are described. They are (1) thermal decomposition of indium phosphide for electronic device application, (2) thermal decomposition of polyethylene terephthalate and its kinetic analysis, (3) thermal decomposition of polymethyl methacrylate in relation to its terminal groups, (4) thermal endurance life estimation of polymeric insulating materials, and (5) volatilization of solvent, unreacted hardener and impurities from epoxide resin. New applicabilities, such as controlled rate thermal analysis, switching of atmosphere, and kinetic analysis of parallel reactions, are introduced, and standards for temperature calibration are discussed.
J. Mass Spectrom Soc. Jpn., 46(4), 283-288 (in Japanese), 1998
A temperature programmed pyrolysis-mass spectrometric (TPPy-MS) system was developed for evolved gas analysis for polymeric materials. In this system, a temperature programmable micro-furnace pyrolyzer was directly coupled with a quadrupole mass spectrometer via a highly deactivated metal capillary. Thus developed system was applied to the following characterization of various functional polymers: (a) Thermal degradation process of a flame-retarded poly (butylene terephthalate) (FR-PBT) with a synergistic flame-retardant system based on a brominated polycarbonate (Br-PC) and Sb2O3 was investigated. During the degradation of FR-PBT, the evolution of brominated phenols and HBr proved to be closely related to the synergistic effect of Sb2O3 on the decomposition of Br-PC in the flame retardant system. Furthermore, the evolution of the flame poisoning SbBr3 caused by the synergistic effect of Sb2O3 with Br-PC was also able to be monitored. (b) Chitin derivative/poly(vinyl chloride) (PVC) blends were characterized mainly in terms of their miscibility and sites of the intermolecular interactions. Stepwise degradation apparently in three stages was commonly observed for the blends corresponding to the degradation of the respective blending polymers. However, each degradation peak temperature proved to change correlating to the miscibility of the blends. Moreover, during the dehydrochlorination stage for PVC at relatively lower temperatures below 300oC, the evolution of many characteristic products formed from the chitin derivative was also observed, suggesting that the intimate intermolecular interactions between the chitin derivative and PVC were triggering the degradation of the chitin derivatives which should be stable up to ca. 350oC.
J. Mass Spectrom. Soc. Jpn., 46(4), 289-291 (in Japanese), 1998
Applicability and prospect of TG-MS (Thermogravimetry coupled with Mass spectrometry) was discussed by focusing to ceramic thin films and fine powders. TG-MS is applicable to clarify the formation process of the metal oxide films from the precursors which were, for example, dip-coated onto the substrate. TG-MS was discussed in comparison with the TDS (Thermal Desorption Spectroscopy) which was widely applied to the analysis of thin films. The investigation of the formation process of ceramic fine powders using TG-MS was also refered.
J. Mass Spectrom. Soc. Jpn., 46(4), 292-295, 1998
Indium acetate, a promising material for producing indium oxide films (Indium-Tin-Oxide transparent conductive films) by a dip coating, was synthesized and analyzed. The process of oxide formation in nitrogen and helium atmosphere was investigated by so-called TG-DTA-MS i.e., thermogravimetry (TG) and differential thermal analysis (DTA) coupled with Evolved Gas Analysis (EGA) by mass spectrometry (MS) operated simultaneously. The thermal decomposition proceeded by gas evolution of water vapor and acetic acid followed by gas evolution of acetone and carbon dioxide at the higher temperature. The process in air atmosphere terminated at slightly earlier with an exothermic mass loss accompanying a rapid evolution of acetone, water vapor and carbon dioxide; the evolved heat by combustion of acetone seemed to accelerate the thermal decomposition. The formula for indium acetate was estimated to be InOH(CH3COO)2 (basic acetate) by which the above reactions were explained satisfactorily.
J. Mass Spectrom Soc. Jpn., 46(4), 296-298, 1998
The thermal decomposition of basic nickel carbonate (BNC) was investigated using TG-MS. It was found to proceed in two steps, and H2O and CO2 evolved during each step. Measurement of the apparent activation energies of the evolving H2O and CO2 showed that those during the second step were about twice those during the first step. These results indicate that CO2 evolving from BNC during the first step is in a state such as coordinated water.
J. Mass Spectrom Soc. Jpn., 46(4), 299-303, 1998
Simultaneous TG-MS (TG: thermogravimetry and MS: mass spectrometry) measurement, a mass spectrometer connected with a thermogravimetry by a transfer line and an interface or by the skimmer coupling, was used to investigate decomposition of urea. A simple decomposition reaction of urea to form ammonia and cyanic acid (or isocyanic acid) was determined. The low intensity ratio of m/z 43 to m/z 17 was attributed to that the cyanic acid react with water to form carbon dioxide. Polymerization and decomposition of the polymers were more predominant later than the simple decomposition stage.
J. Mass Spectrom Soc. Jpn., 46(4), 304-307, 1998
Thermal behaviours of the inclusion complexes of cholic acid with propanol, acetylacetone, propylbenzene and water have been studied by TG-DTA-MS and DSC. Liberation processes of water from their inclusion complexes carried out in a single step. Those of propanol, acetylacetone, propylbenzene from the corresponding inclusion complexes proceeded in only two stages. The elimination temperatures, enthalpies and the activation enthalpies of eliminations have been determined. Increasing orders of the enthalpies of decomposition and the activation energies of the initial elimination are agreed with modes of molecular packing reported.
J. Mass Spectrom Soc. Jpn., 46(4), 308-316 (in Japanese), 1998
Pyrolysis mechanism of cellulose and it's roasted odor were studied by odor sensor, GC-MS and TG- MS. The roasted odor was generated from 170oC when cellulose was heated and pyrolized. Odor sensor made of tin oxide semiconductor thin film detected the odor products at 170oC which was almost the same temperature that a human nose could detect. The human and the artificial nose could be understood to sense the same evolved gas among the decomposition products. We analyzed the decomposition products of cellulose and found levoglucosan as a main product around 200- 300oC by GC-MS under He condition. TG-MS study was carried out under air condition and levoglucosan was detected. Levoglucosan (m.p. 182oC, b.p. 280oC) was estimated to sublimate over the temperature of 200oC. When the cellulose pyrolized, the chemical weak bonding of -O- was scissored randomly. Finally this scission stopped when it created the monomer unit of cellulose, i.e. levoglucosan. Considering these facts we concluded the roasted odor by the decomposition of cellulose must be levoglucosan.
J. Mass Spectrom Soc. Jpn., 46(4), 317-325 (in Japanese), 1998
The evolved gas analysis (EGA) was carried out using the odor sensor under the atmospheric condition. The abilities of adsorption and desorption to carbon fibers, silk and cotton were compared by trimethylamine as one of the environmental malodor standard reagents. The weight loss of trimethylamine was too small to detect by TG although the odor sensor could measure these desorbed molecules by increasing temperature quantitatively and accurately. This result showed that the amount of trimethylamine desorbed from carbon fibers was much larger than that from silk and cotton because carbon fibers had the porous structures. On the contrary, the least amount of adsorption and desorption was observed by silk that is considered to be the best textile fiber without stain against the malodor. EGA of electric wire made of PVC was analyzed and the Pyrolysis gases were detected at 100oC. EGA of pure PVC showed the Pyrolysis gases from 200oC. At the lower temperature, the odor sensor could catch the Pyrolysis products of plasticizers contained in PVC electric wire. TG-MS of pure PVC detected HCl and benzene at 200oC. API-MS analysis was also carried out and showed the very high sensitivity to the decomposition products of benzene even at 60oC.
J. Mass Spectrom Soc. Jpn., 46(4), 326-331 (in Japanese), 1998
Soot samples produced by the combustion of gasoline, kerosene, light oil, three types of heavy oils, tar, light and heavy naphtha, soybean oil, olive oil and seven alkanes were pyrolyzed at 590oC by a Curie point pyrolyzer and evaluated by gas chromatography/mass spectrometry (GC/MS). Isoquinoline, dibenzofurane and naphthalenecarbonitrile in the tar soot and ethylnaphthalene and dimethylnaphthalene in the soots of heavy oil and tar were useful specific components for identification of the soots. In addition, sulfur containing compounds such as dibenzothiophene, methyldibenzothiophene, dimethylnaphtho[2,3-b]thiophene were identified in the soot of light oil, three types of heavy oils, tar and heavy naphtha, all of which contain sulfur considerably.
J. Mass Spectrom Soc. Jpn., 46(4), 332-335 (in Japanese), 1998
A novel selective sampling device was proposed for an evolved gas analysis (EGA) method using a temperature programmable pyrolyzer with a GC detector such as mass spectrometer. The new method is based on the indirect flow switching technique free of a direct mechanical valve utilized for conventional EGA systems. This sampling device enabled the selective sample introduction of any desired temperature ranges for the products observed in EGA to the associated detection system. From the observed data for several polar compounds by the measuring system equipped with this sampling device, it was confirmed that the system had little dead volume and less active inner surface. Furthermore, it was demonstrated that the selective introduction of evolved products was successfully applied for the characterization of a complex formulated polymeric material.
J. Mass Spectrom Soc. Jpn., 46(4), 336-341 (in Japanese), 1998
In this work, a method for analysis of vulcanization accelerator in vulcanized rubber was developed by using a pyrolyzer (Py) - gas chromatograph/atomic emission detector (GC/AED) and gas chromatograph/mass spectrometer (GC/MS). Thermal desorption - GC/AED made it possible to monitor the sulfur compounds and amines decomposed from vulcanization accelerator under vulcanization. Specified peaks of AED chromatograms were identified by the corresponding MS data. Qualitative analysis of these compounds could estimate original chemical structures of the vulcanization accelerators. Temperature programmed Py-AED made it possible to get evolved gas profile of each elements. Temperature programmed Py-MS could get evolved gas profile of each compounds from specific ion chromatograms.
J. Mass Spectrom Soc. Jpn., 46(4), 342-346 (in Japanese), 1998
An application of thermospray ionization mass spectrometry to a rapid on-line characterization of thermal decomposition of new chemical entities was investigated, which is beneficial in the early stage of pharmaceutical development. Relative abundance of product protonated molecular ions was measured as a function of the probe temperature at a thermospray tip. Thermal decomposition curves for PNU-52047 and PNU-100766 were constructed from which decomposition pathways were elucidated. It was found that PNU-52047 decomposes via an elimination of water and/or methanol and a methyl group whereas PNU-100766 does via an opening of the oxazolidinone ring resulting from an elimination of CO2 or CO. Activation energies were elucidated from the Arrhenius plots for relative abundance of the non-decomposing drug parent ion. The activation energy for thermal decomposition of PNU-52047 was ca. 9.4 kcal mol-1 which indicates that this drug is quite unstable in solution state. Regarding to PNU-100766, a comparison of the Arrhenius plots obtained from this on-line thermospray method and those in terms of the regulatory thermal stress-study for the sterile solution for injection in the tightly sealed vials led that decomposition in both experiments occurs with the same activation energy of ca. 26 kcal mol-1 but with considerably different frequency factors.
J. Mass Spectrom Soc. Jpn., 46(4), 347-352 (in Japanese), 1998
Reaction path of two kinds of epoxy resins were studied by MALDI-TOFMS. In the case of ringopening reaction of novolac epoxy resin with acetic acid, epoxy ring was opened to be mono-acetylated diol by acetic acid, consequentry hydroxy group formed by ringopening reaction was acetylated. In the case of ringopening polymerization of bisphenol A epoxy resin with N,N'-dimethylethylenediamine, various kinds of polymers were formed and molecular weights of the polymers were increased corresponding to reaction time. In both cases, structures of epoxy resins and reaction products were determined by FABMS/MS or LSIMS/MS.
J. Mass Spectrom Soc. Jpn., 46(4), 353-356 (in Japanese), 1998
Thermal and electrical properties of self-doped polyaniline (PAn) having carboxyl group have been investigated. Thermogravimetry-mass spectrometric (TG-MS) results demonstrated that the carboxyl substituent decomposes in the temperature range between 100 and 350oC, followed by the decomposition of the polymer backbone above 350oC. The substituent was suggested to be in the form of -COO- and -COOH from the FTIR measurements. The existence of the negative carboxyl group resulted from the interaction with the positively charged PAn chain. The thermal decomposition of carboxyl group at 150oC and below did not affect the conductivity of the polymer, but it dropped considerably in the decomposition on temperature above 150oC. This observation indicates that the decarboxylation of the -COOH substituent, which is not associated with the dopant anion, proceeds more readily than that of the -COO- substituent.
J. Mass Spectrom Soc. Jpn., 46(4), 357-360 (in Japanese), 1998
In the material research, TG-MS, pyrolysis-GC are often used in order to obtain the thermal properties of the materials such as gas evolution. On the other hand, TPD (Temperature Programmed Desorption) technique was used for the solid acid-base characterization in the catalysis research. We designed new TPD-MS (Temperature Programmed Desorption or Decomposition Mass Spectrometry) instrument for comprehensive use. Some applications taken by TPD-MS were shown in the following characteristics. (1) Evolved gas analysis which has more than one order of magnitude higher sensitivity than TG-MS, (2) analysis of chemical adsorption and desorption properties, (3) thermal decomposition analysis of air sensitive materials.
J. Mass Spectrom Soc. Jpn., 46(4), 361-364 (in Japanese), 1998
Thermally decomposition products from virgin and flame retarded polyesters were investigated by using GC-MS method. Effects of flame retardation on polyester were found to appear at relatively lower temperature. Difference between retardants which contain phosphorus or bromine was shown clearly. Phosphorus-contain polyester emitted more amounts of carbon monoxide, carbon dioxide, and benzene than other polyesters. Bromine-contain polyester emitted less amounts of gaseous products than other polyesters.
J. Mass Spectrom Soc. Jpn., 46(4), 365-373 (in Japanese), 1998
Direct coupling of TG/DTA to MS is achieved using a capillary tube as interface. Inner diameter and length of the capillary tube are optimized to 0.25mm and 5m, respectively. The period necessary to start the measurement after setting a new sample into the TG/DTA is minimized to 10 minutes by increasing the initial purge gas flow rate to 1000ml/min. Quantitative MS analysis of calcium oxalate is achieved. The repeatability of measurements are + or - 1.5% for CO2 and + or - 6.1% for H2O. Analysis in He+20%O2 atmosphere is proved to be fully possible and effective to understand the thermal behavior of the samples in air. Examples of TG/DTA-MS results for various materials are reported; polymers (nylon-6, high-density polyethylene and polystyrene), a clay, mineral (sepiolite) and PYREX glass are measured and their thermal behavior are understood clearly and quickly.
J. Mass Spectrom Soc. Jpn., 46(4), 374-379 (in Japanese), 1998
Kinetic study in thermal decomposition of polymeric materials has been examined by means of simultaneous thermogravimetric-mass spectrometric (TG-MS) analysis and controlled-rate thermogravimetry (CRTG) which belongs to controlled-rate thermal analysis (CRTA). We proposed rate-jump control (RJC) method in which the preselected two decomposition rates are controlled alternately at the interval of the constant weight loss percentage, in order to estimate the apparent activation energy without preliminary knowledge of the actual mechanism. The reaction models governing the thermal decomposition of poly(caproamide) (Nylon-6) and poly(methyl methacrylate) (PMMA) will be easily attributed by the shape of curves observed from constant decomposition rate control (CDRC) experiments. The each kinetic parameter sets were estimated from the RJC data and the evolved gas components obtained from simultaneous TG-MS system, and the corresponding kinetic models were reaction of a random scission in the main chain with L=2 (L is the smallest polymerization degree of polymer that does not evaporate) and 1.5 order reaction of depolymerization, respectively. It is concluded that the combination of analytical techniques by the thermogravimetric curves obtained from CRTG and chemical species obtained from TG-MS, is capable of establishing the uniqueness of kinetic parameters and reaction models, when dealing with thermal decomposition reaction in polymers.
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