Thermal degradation mechanism and thermal degradation rate constants of poly(epichlorohydrin-co-ethylene oxide) derived from GC-MS pyrolysis studies (2023)

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Polymer degradation and stability Abstract Introduction unit excerpts materials Pyrolysis, GC and GC-MS instruments Characterization of poly(epichlorohydrin-)plus-Ethylene oxide)-Elastomerpyrolysis products conclusions thanks bibliographical references(22) I humiliate politics. prick. I humiliate politics. prick. I humiliate politics. prick. I humiliate politics. prick. EURO. Polym. J. I humiliate politics. prick. I humiliate politics. prick. electrochem. Acta Sun. mother energy sun. cells ionic solid I humiliate politics. prick. Quote from (10) A study of the pyrolytic decomposition pathways of HTPB and HTPE using mass spectrometry Post-chemical grafting of poly(methyl methacrylate) into commercial renewable elastomers as effective modifiers for polylactide blends Development of a new gas chromatography/pyrolysis mass spectrometry method for the analysis of thermal degradation products of poly(lactic acid) Photodegradation of polyglycidol in aqueous solutions under UV irradiation Mechanistic effects of plastic degradation Thermal Degradation of Polymeric Materials, 2nd Edition Featured Articles (6) Poly(vinylidene fluoride) as a porogen for the preparation of nitrogen-enriched porous carbon electrode materials by pyrolysis of melamine resin Excellent hexose fermentation capacity of the xylitol-producing yeast Candida guilliermondii FTI 20037 Temperature niche conservatism and a strong genetic structure are involved in the colonization of the transpanamanian Matudaea (Hamamelidaceae) in Andean forests Improved mechanical and dielectric properties of a hydroxyl-terminated polybutadiene-modified epoxy resin Analysis of bacterial diversity and efficiency of continuous removal of Victoria Blue R from wastewater using a fixed-bed bioreactor Applied Potentials Regulate Residual Hydrogen Recovery from Acidic Wastewater: Effect of Biocathodic Buffering Capacity on Process Performance References

Polymer degradation and stability

Volume 81, Issue 3,


, pages 463-472

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The mechanism of thermal degradation andkinetic parametersfor general degradation to poly(epichlorohydrin-)plus-ethylene oxide)Elastomerwere studied using pyrolysis-gas chromatography-mass spectrometry (pyrolysis-GC-MS) techniques. In this study, the total volatile products of elastomer pyrolysis were measured as total ion current (TIC) in the mass spectrometer at different temperatures. Information about the components within the TIC was obtained from selected ion current (SIC) measurements of different ionsm/zindicators. betweenm/zratios corresponding to its ions were observedm/zof 35, 36, 37 and 38 confirmed that HCl is one of the pyrolysis products. SIC metrics for a variety of other potential applicationsdegradation productswere studied to evaluate the general structures, and these showed that a wide range of lowMolmashydrocarbons andChlorkohlenwasserstoffethey arise during the thermal degradation of the elastomer. The results suggest that an important mechanistic process is thisDepolymerizationof macroradicals and that hydrogen abstraction from a carbon atom adjacent to a CÀO bond is an important process for the formation of volatile products. This information led to the hypothesis of a possible mechanism for the thermal degradation of the elastomer. quantitativelyKinetic Measurementswere obtained by evaluating the total volatile production rate using the TIC obtained from sequential pyrolysis experiments. The data leading to this general rate constant (K) has been interpreted in various ways, e.g. B. according to the methods of Ericsson, Guggenheim and Kezdy-Jaz-Bruylants. The mean values ​​obtained for this global rate constant were 0.16 ± 0.03, 0.25 ± 0.03, and 0.55 ± 0.20 s−1for pyrolysis temperatures of 350, 387 or 400 °C.


In recent years, pyrolysis gas chromatography-mass spectrometry (pyrolysis-CG-MS) has been widely used for the separation and identification of volatile products from polymer pyrolysis [1], [2]. In this technique, the mass spectrometer is used as a gas chromatography (GC) detector, the sensitivity of which is at least as good as that of flame ionization detectors (FIDs) and, more importantly, it offers the opportunity to characterize the components with the chromatographic peaks of pyrolysis fragments bound together. An additional advantage is that mass spectrometers permanently detect and measure gases and other small molecules to which FID detectors are insensitive [3], [4]. Advances in this technique, such as the design of pyrolysis units, the use of sufficiently small samples, and appropriate experimental design, have provided reliable quantitative data that can be used to obtain mechanistic information about degradation processes and/or to infer the initial Polymer structure [1], [5].

The present study deals with the thermal stability of poly(epichlorohydrin-)plus-ethylene oxide). The characterization of the pyrolysis degradation products of this elastomer is of interest as it is a copolymer that exhibits a balanced physical property profile as well as high resistance to ASTM solvents and oils at moderate temperatures [6]. Because of this, it has found many applications in the aerospace and automotive industries [6]. In addition, in recent years, this copolymer has attracted attention in the fields of batteries and electronic devices because it can be used as a solid polymer electrolyte with good ionic conductivity at room temperature when complexed with an inorganic salt [7], [8] . Several studies have been published in this area describing its use in batteries, capacitors, electrochromic displays and photoelectrochemical cells [9], [10], [11]. Good thermal stability of the polymer is desirable for these applications. Therefore, characterizing the volatile degradation products and measuring their individual specific rates helps to understand which factors may be responsible for the thermal aging of this copolymer.

McGuire et al. [12] studied poly(epichlorohydrin) and poly(epichlorohydrin-)plus-ethylene oxide) elastomers by the GC-MS pyrolysis technique and suggested that their pyrolysis products damage the capillary columns. This was attributed to the fact that the aliphatic alcohols formed during the pyrolysis were completely adsorbed on the columns, which led to non-reproducible results. The technique used by these authors to solve this problem was direct pyrolysis mass spectrometry (Py-MS). They studied the main products of poly(epichlorohydrin) in the form of ionsm/z41 em/z43 resulting from the loss of X.Th3Cl, the ionsm/z55 em/z57 resulting from the loss of HCl and ionm/z93, corresponding to protonated epichlorohydrin. A spectrum similar to that of poly(epichlorohydrin) was obtained from the pyrolysis of poly(epichlorohydrin).plus-ethylene oxide) elastomer, except for its relative ion intensitiesm/z29 em/z45. The authors hypothesized that these ions were formed by a free radical reaction that occurred during thermal degradation. However, his study failed to distinguish between ions characteristic of thermal degradation mechanisms and those of electron impact fragmentation.

Recently, Lehrle et al. [13], [14] obtained excellent results using pyrolysis GC-MS to evaluate the thermal degradation mechanisms of chlorine-containing polymers. For example, this group studied the thermal stability properties of neoprene/chlorobutyl rubber composites before and after artificial aging [14]. They demonstrated the effectiveness of the 5% phenylmethylsiloxane hemipolar column in the separation of degradation products and the reproducibility of the results.

The aim of this work is to investigate the thermal degradation of poly(epichlorohydrin).plus-ethylene oxide) elastomer with the GC-MS pyrolysis technique not only to characterize the volatile products but also to measure the relevant kinetic parameters and to formulate possible degradation mechanisms.

unit excerpts


A Poli(epicloridrina-plus-ethylene oxide) (50/50) Elastomer sample, Epichlomer-C, was obtained from Daiso Co., Ltd. Delivered. (Osaka, Japan). Analytical grade tetrahydrofuran, THF (Riedel-de Haen, GmbH) was used as solvent. In 1 g l−1A stock polymer solution in THF was used throughout the work.

Pyrolysis, GC and GC-MS instruments

A Fisons GC8000 Series GC was used, the effluent of which went directly to the source of a Thermoquest MD800 quadrupole mass spectrometer, which scans and records 70 eV electron impact mass

Characterization of poly(epichlorohydrin-)plus-Ethylene oxide)-Elastomerpyrolysis products

The chemical structure of the elastomer, Fig. 1, suggests the possibility that during its thermal degradation it not only decomposes as a polyether but also dehydrochlorides. In general, polyethers show a wide variety of thermal degradation mechanisms, as both radical and ionic mechanisms can occur during degradation, as the presence of polar groups facilitates the ionic mechanism in the degradation of condensation polymers [18]. Such mechanisms in the thermal degradation of


The results discussed above advance our understanding of the thermal degradation of poly(epichlorohydrin-)plus-ethylene oxide) elastomer. Generally, during the degradation of this elastomer, the depolymerization of macroradicals formed by the homolytic cleavage of CO and C–C bonds and the abstraction of hydrogen from a carbon atom adjacent to the C–O bond is one of the most important processes in the degradation. of this elastomer the formation of highly reactive alkyl radicals.

The average values ​​found for the global rate constant,K,


This work was carried out in the laboratories of the University of Birmingham, for which the authors would like to thank FAPESP for the scholarship and financial support (Proc. No. 98/14198-5 and 96/09983-0). The authors also thank Daiso Co. Ltd., Osaka, for providing the polymer samples.

bibliographical references(22)

  • RSLehrleand others

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      Plastics have become an integral part of human life. Its massive use is a major environmental and economic concern, which has prompted researchers and technologists to induce varying degrees of degradation in plastics. These degradation processes can be better elicited if their mechanistic implications are properly understood. A better understanding of the mechanisms of these damages is also suggested to facilitate the proper development of alternative waste management strategies. Given the facts about the degradation of plastics, in this review article we discuss different types of polymer degradation and their mechanisms, including photooxidative degradation, thermal degradation, ozone-induced degradation, mechanochemical degradation, catalytic degradation, and biological deconstruction. This article also reviews the various methods used to study these changes and the factors that influence these changes.

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