International Symposium on Analytical Pyrolysis of Polymers, held jointly with the Fourth Conference on Analytical Pyrolysis in Japan. January 24–25, 2002, Nagoya, Japan (original) (raw)
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Journal of Analytical and Applied Pyrolysis
Journal of Chromatography A, 1980
The polymerization of acrylonitrile to polyacrylonitrile (PAN) has been studied using several solvents: N,N-dimethylformamide (DMF), hexane, toluene, water, and in bulk form (no solvent). The addition of DMF is the only case where both monomer and polymer are soluble in the solvent. Thermal analyses of the resultant products after polymerization have been performed by differential scanning calorimetry and pyrolysis-gas chromatography/ mass spectrometry. The effect of the solvents employed as media for polymerization is interpreted from the results of the thermal and structural (X-ray diffraction) methods. The polymer samples obtained when using water or toluene as solvents have the greater content of amorphous components compared to the others. The amide molecules are difficult to completely eliminate in the product obtained after the polymerization reaction and even after prolonged heating at 110°C and remain occluded. DMF can be considered to exert a plasticized effect on PAN and is even capable of forming complexes by dipolar bonding.
Analysis of polymers using evolved-gas and direct-pyrolysis techniques
Analyst, 1994
Thermal analysis of polystyrene, poly(p-methylstyrene) and poly(a-methylstyrene) has been carried out using evolved-gas analysis by infrared and mass spectrometry, and directpyrolysis analysis by mass spectrometric techniques. Evolved-gas analysis, both by infrared and mass spectrometry, reveals features due mainly to the corresponding monomers or stable, volatile, and low relative molecular mass degradation products. In direct-pyrolysis mass spectrometry, however, primary decomposition products and heavier fragments such as dimers and trimers can also be detected. The ion-temperature profiles of the corresponding monomer ions reveal information about the thermal stability of the polymers.
Pyrolysis/mass spectrometry and pyrolysis/gas chromatography/mas spectrometry analysis of polymers
Rapid Communications in Mass Spectrometry, 1991
The potential of pyrolysis/gas chromatography/mass spectrometry in the study of the chemical composition and structure of polymers and copolymers is demonstrated, and results obtained on polysilane copolymers, phenolformaldehyde polycondensates and diol modified epoxy resins are presented. Temperatureltime-resolved pyrolysis mass spectrometry, carried out in the direct inlet of a mass spectrometer, revealed the presence of monomer and oligomer residues and of volatile additives in epoxy resin samples. Basic information was also obtained on the mechanism of thermal decomposition reactions in polysilane copolymers and diol modified epoxy resins.
Lc Gc North America
The analytical pyrolysis technique hyphenated to gas chromatography–mass spectrometry (GC–MS) has extended the range of possible tools for the characterization of synthetic polymers and copolymers. Pyrolysis involves thermal fragmentation of the analytical sample at temperatures of 500–1400 °C. In the presence of an inert gas, reproducible decomposition products characteristic for the original polymer or copolymer sample are formed. The pyrolysis products are chromatographically separated using a fused-silica capillary column and are subsequently identified by interpretation of the obtained mass spectra or by using mass spectra libraries. The analytical technique eliminates the need for pretreatment by performing analyses directly on the solid or liquid polymer sample. In this article, application examples of analytical pyrolysis hyphenated to GC–MS for the identification of different polymeric materials in the plastic and automotive industry, dentistry, and occupational safety are ...
Characterization of substituted polyacetylene microstructure by pyrolysis gas chromatography A series of substituted acetylenes has been polymerized with WOCl 4 /Ph 4 Sn metathe-sis catalyst and [Rh(cod)OMe] 2 insertion catalyst, and the thermal degradation of the polyacetylenes prepared has been studied using pyrolysis capillary gas chromatography (Py-GC) with flame ionization and mass spectrometric detection to obtain information on the effect of the catalyst on the head-tail (H-T) isomerism of polyacetyle-nes (poly(phenylacetylene), poly[(4-methylphenyl)acetylene], poly(benzylacetylene), poly[(2-fluorophenyl)acetylene], poly[(3-fluorophenyl)acetylene], and poly[(4-fluoro-phenyl)acetylene]). Cyclotrimers have been found to be the main pyrolysis products in all cases. Direct Py-MS connection was used to determine the temperature profiles of the released pyrolysis products. 1,3,5-Trisubstituted benzenes were found to be the predominant pyrolysis products of the polymers prepared with the insertion catalyst, which proves the presence of long head-to-tail sequences of monomeric units in these polyacetylenes. On the other hand, both 1,2,4-and 1,3,5-trisubstituted benzenes are present in significant amounts in the pyrolysis products of polymers prepared with the metathesis catalyst, which proves the presence of a significant content of the head-to-head (HH) and tail-to-tail (TT) linkages in these isomers of polyacetylenes. Contents of the regular (HT) and inverse (HH-TT) monomer linkages (RML and IML, respectively) in polymer chains were determined from the relative amounts of di-, tri-, and tetrasubstituted benzenes found in the Py-GC products.
Mass spectral analysis of low-temperature pyrolysis products from poly(ethylene glycol)
Journal of Analytical and Applied Pyrolysis, 2000
A poly(ethylene glycol) sample of average molecular weight 2000 was subjected to low temperature pyrolysis. The polymer was pyrolyzed in Pyrex tubes (sealed at one end) placed at the end of the carrier gas inlet in a gas chromatograph. Pyrolysis was carried out under argon flow in the temperature range 150-325°C. After pyrolysis, the residue in the pyrolysis tube was analyzed by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and by direct probe chemical ionization (isobutane CI-MS). Eight series of oligomeric pyrolyzates were characterized by MALDI-MS and CI-MS. Assignment of chemical structures was aided by tandem mass spectrometry (CI-MS/MS) and by deuteration of hydroxyl end groups in the pyrolyzate. Pyrolysis of PEG ensues as low as 150°C in inert atmosphere. At the lowest temperatures the dominant oligomeric products have hydroxyl and 'ethyl ether' end groups. At higher temperatures, 'methyl ether' and 'vinyl ether' end groups become more abundant in the pyrolyzates. The pyrolysis experiments indicate that the decomposition scheme is free radical in nature. Cleavage of C O bonds is preferred at the onset of pyrolysis; hydrogen abstraction following C O homolysis produces hydroxyl and 'ethyl ether' end groups. At higher temperatures, the abundances of the 'methyl ether' and 'ethyl ether' end groups become more balanced as relatively more C C cleavage occurs. The increasing abundance of 'vinyl ether' end groups at higher pyrolysis temperatures is primarily due to dehydration of hydroxyl end groups.
Pyrolytic degradation of common polymers present in packaging materials
Journal of Thermal Analysis and Calorimetry, 2019
Pyrolysis of polymers with widespread use, such as PET, HDPE, PVC, LDPE, PP and PS, been utilized extensively as plastic packaging materials, is the subject of this study. Low biodegradability and short life of polymers used in packaging have resulted in enormous waste amounts; thus, polymer recycling is more than imperative for modern, developed municipalities. One of the main problems is the production of either feedstock or valuable secondary materials, without additional environmental burden. In this context, the thermochemical methods lead not only to recycling of plastics but also to the creation of specific petrochemical industrial products, and the profit will be considerable. Pyrolizer accompanied by a GC/MS is a useful instrumental array for the study of the thermal degradation of several types of polymers. It is resulted that the cracking temperature affects the type and number of the segments produced, since higher temperatures strongly parcel the polymer chain to monomers and release smaller molecules, while at lower temperatures it is more likely to detect oligomers. Chromatographic results were sometimes complicated due to the isomers produced during pyrolysis. It is mainly supposed that polyolefins decompose through a radical process, where depolymerization propagates until H-abstraction occurs. PVC behaves differently due to the presence of halogens, fond to chain reactions, while for PS the main fragments eluted are styrene monomer, dimmer and trimmer. From PET analysis, it is concluded that the products of decomposition include CO 2 , PhCOOH, PhCOOCH = H 2 and other aromatic vinyl-substitutes, while PET depolymerization is keen on CaO catalysis for lower decomposition temperatures.
LC GC Europe
The analytical pyrolysis technique hyphenated to gas chromatography–mass spectrometry (GC–MS) has extended the range of possible tools for the characterization of synthetic polymers and copolymers. Pyrolysis involves thermal fragmentation of the analytical sample at temperatures of 500–1400 °C. In the presence of an inert gas, reproducible decomposition products characteristic for the original polymer or copolymer sample are formed. The pyrolysis products are chromatographically separated using a fused-silica capillary column and are subsequently identi" ed by interpretation of the obtained mass spectra or by using mass spectra libraries. The analytical technique eliminates the need for pretreatment by performing analyses directly on the solid or liquid polymer sample. In this article, application examples of analytical pyrolysis hyphenated to GC–MS for the identi" cation of different polymeric materials in the plastic and automotive industry, dentistry, and occupational s...
Study of Pyrolysisis of Polymers and Coal and Co-Pyrolysis of Their Blends, Kinetics of the Process
Transactions of the VŠB - Technical University of Ostrava, Mechanical Series, 2012
Amount of polymer waste increase every year and for this reason upgrading of this waste is a necessity. Nowadays waste disposal and incineration of polymers waste are the most frequently used methods which (i) did not allowed chemical and energy utilization and (ii) are not environmentally friendly. Pyrolysis and co-pyrolysis provide an attractive way to dispose of and convert polymer waste and coal into higher value fuel and the specific benefits of this method potentially include many environmental friendly advantages. Pyrolysis and co-pyrolysis has been studied using termogravimetry apparatus NETZCH TG-DTA STA 409 EP. The pyrolysis of all polymers except for scrap tyres was a one-step process and temperature range was narrower than for coal pyrolysis. The overlapping temperature range for pyrolysis of polymers and coal was 200-600°C. The synergic effect and kinetics of co-pyrolysis of polymers and coal has been studied in the given temperature range. The addition of polymers to coal led to (i) the enhancement of weight loss of brown coal, (ii) the shift of temperature of the max pyrolysis speed and (iii) the slight influence of E A of coal pyrolysis. Abstrakt Množství odpadních polymerů každoročně stoupá a jejich recyklace je velmi důležitá. V dnešní době je největší část těchto odpadů ukládána na skládky nebo spalována. Tyto dvě metody však nejsou příliš vhodné (nedochází k chemickému ani energetickému využití materiálu) a nejsou ani šetrné k životnímu prostředí. Pyrolýza a ko-pyrolýza jsou vhodné recyklační metody umožňující přeměnu odpadních polymerů a uhlí na paliva s vyšším energetickým obsahem a jsou šetrné k životnímu prostředí. Pyrolýza a ko-pyrolýza vybraných polymerních materiálů s hnědým uhlím byla studována pomocí dynamické termogravimetrie na přístroji LECO TG-DTA STA 409 EP firmy NETZCH. Pyrolýza polymerů, kromě odpadních pneumatik, probíhala v jednom stupni a v užším teplotním intervalu než pyrolýza uhlí. Teplotní interval, kdy docházelo k pyrolýze polymeru i uhlí byl 200-600°C. V tomto teplotním intervalu byla rovněž studována kinetika ko-pyrolýzy a synergický efekt studovaných polymerů a hnědého uhlí. Nejvyšší pozitivní synergický efekt vedoucí ke zvýšení hmotnostního úbytku hnědého uhlí a rychlejší pyrolýzy při nižších teplotách měl ze studovaných polymerů polypropylen.