Evolved Gas Analysis Research Articles

Multianalytical approach to characterize composition and degradation processes of synthetic high-fashion textiles from the Nanni Strada Design Studio archives

Abstract Synthetic textiles are constituents of heritage objects and garments often displayed in museum collections or preserved in archives, presenting unprecedented and specific conservation challenges. These issues need to be addressed assessing degradation processes, and developing targeted restoration and preventive conservation practices. The present work aims at characterizing the composition of high fashion garments and design textiles by Nanni Strada conserved in the archives of Nanni Strada Design Studio (Milan). To identify the chemical composition of the fibers used for the manufacturing, and to investigate the degradation processes affecting the objects, the materials were investigated by Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), Evolved Gas Analysis coupled to Mass Spectrometry (EGA-MS), and multi-shot Pyrolysis coupled to Gas Chromatography and Mass Spectrometry (Py-GC/MS). The results will contribute to a better knowledge of the chemical properties of the textiles produced in the 1970s, and to plan conservation and exhibition strategies.

Iron speciation in soil size fractions under different land uses

Iron (Fe) (oxyhydr)oxides represent a significant phase for the organic carbon (OC) stabilization. Due to their high surface areas, short-range-ordered Fe minerals, like ferrihydrite, show a higher ability to stabilize OC than crystalline secondary minerals, like lepidocrocite, goethite, and magnetite. However, how Fe phases and their crystallinity relate to soil organic matter (SOM) composition is still not completely known. We investigated Fe solid phase speciation in two soil particle size fractions (i.e., fine sand — FSa — and fine silt and clay — FSi + Cl —), isolated from coniferous (CF) and broadleaved forest soils (BF), grassland soils (GL), and technosols (TS). All samples were characterized by Fe K-edge extended X-ray absorption fine structure (EXAFS) and X-ray diffraction, and a subset by 57Fe Mössbauer spectroscopy. Further, ramped combustion thermal analyses (coupled differential scanning calorimetry (DSC) and CO2 evolved gas analysis (CO2-EGA)) were used to evaluated SOM stability. With the only exception of TS, goethite was the main Fe phase in FSa fractions, whereas less crystalline phases (i.e., ferrihydrite, based on EXAFS) dominated the FSi + Cl fractions. The proportion of goethite and ferrihydrite in both fractions decreased with increasing OC content, while that of Fe(III)-SOM in FSa increased with increasing OC content. Mössbauer and EXAFS data clearly indicated a presence of hematite in GL soils. Our data suggest that more crystalline Fe forms, like goethite and hematite, may be important for OC abundance in the FSa fraction and in soils with high OC contents, like GL. Thermal analysis showed the dominance of mineral associated organic matter in low-OC soils, and of plant residues in high-OC soils. As a whole, we posit that the FSi + Cl fractions contain Fe phases of less crystallinity because of presumed association with SOM, and that SOM in the FSi + Cl fraction is also more thermodynamically stable than in FSa, although differences are observed across land uses. Our observations suggest that the nature of Fe-SOM interactions can vary substantially with soil particle size and land use, which has important implication for SOM persistence.

Pyrolysis of anaerobic digested residues in the presence of catalyst-sorbent bifunctional material: Pyrolysis characteristics, kinetics and evolved gas analysis

We investigated the potential application of anaerobically digested residues for generating bioenergy in the presence of alkali bifunctional material, sodium zirconate (Na2ZrO3, NZ) using a thermogravimetric analyzer connected to a mass spectrometer. Isoconversional kinetic models, compensation effect and master-plots method were used on data obtained under multiple heating rates (10, 15 and 20 °C min−1) to calculate the activation energy (Eα) and pre-exponential value (A) and reaction mechanism. The average Eα for blend samples C-DSW (NZ mixed with digested municipal solid waste (DSW)), and C-DSM (NZ mixed with digested swine manure (DSM)) were 172.24 and 171.63 kJ mol−1, which were much lower when compared to plain samples, DSW (202.51 kJ mol−1) and DSM (215.22 kJ mol−1). The total gas yields increased by 19.5 and 17.1% for NZ blended samples C-DSW and C-DSM, respectively. In addition, the hydrogen yields also increased by 79 and 44% for C-DSW and C-DSM, respectively.

Evaluating the bioenergy potential of cupuassu shell through pyrolysis kinetics, thermodynamic parameters of activation, and evolved gas analysis with TG/FTIR technique

This research aimed to investigate the physicochemical properties and the pyrolysis performance of cupuassu shell (Theobroma grandiflorum) under a thermogravimetric scale. The pyrolysis experiments were carried out using a pure nitrogen atmosphere and at five heating rates (5, 10, 20, 30, and 40 K min−1). The pyrolysis kinetic triplet was calculated from the DTG thermograms using the isoconversional methods of Friedman, Flynn–Wall–Ozawa, Kissinger–Akahira–Sunose, and Starink combined with the compensation effect and master plots methods. TGA analyses revealed that cupuassu shell pyrolysis follows a devolatilization process of two steps: (1) represented by the two-dimensional diffusion-reaction model (D2), with average activation energies within 102.9–107.5 kJ mol−1, and (2) represented by the fourth-order reaction model (F4) with average activation energies within 176.7–243.0 kJ mol−1. Still, the pre-exponential factor value for the first kinetic stage (1.64×108 min−1) was lower than that of the second kinetic stage (3.19×1010 min−1). As verified, the kinetic triplets efficiently derived the global kinetic expression of cupuassu shell pyrolysis, reproducing reliable data on conversion rates. The evaluation of thermodynamic parameters of activation showed that cupuassu shell is viable biomass for pyrolysis applications, with values of ΔH≠ > 0, ΔG≠ > 0, and ΔS≠ < 0. The TGA-FTIR analysis showed that the evolved pyrolysis products were dominated by alcohols, aldehydes, ketones, organic acids, and aromatic/aliphatic hydrocarbons, supporting the utility of cupuassu shell as a potential source for bio-based chemicals production. In summary, the insights of this study validate the cupuassu shell as a prospective feedstock for producing bioenergy and bio-based chemicals, also bringing useful information for engineering purposes in the design or simulation of large-scale pyrolysis reactors.

A Simple Method for Quantification of Polyhydroxybutyrate and Polylactic Acid Micro-Bioplastics in Soils by Evolved Gas Analysis.

Conventional plastics are being slowly replaced by biodegradable ones to prevent plastic pollution. However, in the natural environment, the biodegradation of plastics is usually slow or incomplete due to unfavorable conditions and leads to faster micro-bioplastic formation. Many analytical methods were developed to determine microplastics, but micro-bioplastics are still overlooked. This work presents a simple method for determining poly-3-hydroxybutyrate and polylactic acid micro-bioplastics in soil based on the thermogravimetry–mass spectrometry analysis of low molecular gases evolved during pyrolysis. For the method development, model soils containing different soil organic carbon contents were spiked with micro-bioplastics. Specific gaseous pyrolysis products of the analytes were identified, while the ratio of their amounts appeared to be constant above the level of detection of the suggested method. The constant ratio was explained as a lower soil influence on the evolution of the gaseous product, and it was suggested as an additional identification parameter. The advantages of the presented method are no sample pretreatment, presumably no need for an internal standard, low temperature needed for the transfer of gaseous products and the possibility of using its principles with other, cheaper detectors. The method can find application in the verification of biodegradation tests and in the monitoring of soils after the application of biodegradable products.

An exceptionally stable and widespread hydrated amorphous calcium carbonate precipitated by the dog vomit slime mold Fuligo septica (Myxogastria)

Biogenic amorphous calcium carbonate (ACC) is typically metastable and can rapidly transform through aging, dehydration, and/or heating to crystalline calcium carbonate. Gaining insight into its structure and properties is typically hampered by its tendency to crystallize over short time periods once isolated from the host organism, and also by the small quantities that are usually available for study. Here we describe an exceptionally stable hydrated ACC (HACC) precipitated by the cosmopolitan slime mold Fuligo septica (L.) F.H. Wigg. (1780). A single slime mold can precipitate up to a gram of HACC over the course of one night. Powder x-ray diffraction (XRD) patterns, transmission electron microscopy images, infrared absorption spectra, together with the lack of optical birefringence are consistent with an amorphous material. XRD simulations, supported by thermogravimetric and evolved gas analysis data, are consistent with an intimate association of organic matter with ~ 1-nm-sized ACC units that have monohydrocalcite- and calcite-like nano-structural properties. It is postulated that this association imparts the extreme stability of the slime mold HACC by inhibiting loss of H2O and subsequent crystallization. The composition, structure, and thermal behavior of the HACC precipitated by F. septica collected over 8000 km apart and in markedly different environments, suggests a common structure, as well as similar biochemical and biomineralization mechanisms.

A new analytical approach to investigate the influence of wood extracts on the curing properties of phenol-resorcinol\u2013formaldehyde (PRF) adhesives

In this study, the interactions between a phenol–formaldehyde resorcinol (PRF) adhesive and water-extractable wood constituents were investigated using combined in-situ FTIR spectroscopy and rheology analysis for a simultaneous examination of the progress of chemical reactions and coherent changes in rheological properties during adhesive curing. Complementary evolved gas analysis and pyrolysis gas chromatography/mass spectroscopy (Py-GC/MS) were performed to detect differences in the final crosslinking and chemical composition of the cured adhesive, respectively. The rheological and chemical analysis results correlated with the tensile shear strength of wood-PRF assemblies. The results showed that adhesive curing was significantly affected by the presence of acidic wood extractives. In particular, the acidic extractives of chestnut wood led to a delay in the resin curing and less final crosslinking of the cured adhesive. This was most likely caused by a reduction in the catalytic effect of the base-catalyzed curing of the adhesive rather than by direct chemical reactions between the extracts and adhesive. These findings can be useful for adapting the resin formulation to the chemistry of acidic wood species.

Mineralogy and diagenesis of Mars-analog paleosols from eastern Oregon, USA

Ancient (4.1–3.7-billion-year-old) layered sedimentary rocks on Mars are rich in clay minerals which formed from aqueous alteration of the Martian surface. Many of these sedimentary rocks appear to be composed of vertical sequences of rocks containing Fe/Mg clay minerals overlain by rocks with Al clay minerals that altogether resemble paleosols (ancient, buried soils) from Earth. The types and properties of minerals in paleosols can be used to constrain the environmental conditions during formation to better understand weathering and diagenesis on Mars. This work examines the mineralogy and diagenetic alteration of volcaniclastic paleosols from the Eocene-Oligocene (43–28 Ma) Clarno and John Day Formations in eastern Oregon as a Mars-analog site. Here, paleosols rich in Al phyllosilicates and amorphous colloids overlie paleosols with Fe/Mg smectites that altogether span a sequence of ~ 500 individual profiles across hundreds of meters of vertical stratigraphy. Samples collected from three of these paleosol profiles were analyzed with visible/near-infrared (VNIR) spectroscopy, X-ray diffraction (XRD), and evolved gas analysis (EGA) configured to operate like the SAM-EGA instrument onboard Curiosity Mars Rover. Strongly crystalline Al/Fe dioctahedral phyllosilicates (montmorillonite and nontronite) were the major phases identified in all samples with all methods. Minor phases included the zeolite mineral clinoptilolite, as well as andesine, cristobalite, opal-CT and gypsum. Evolved H2O was detected in all samples and was consistent with adsorbed water and the dehydroxylation of a dioctahedral phyllosilicate, and differences in H2O evolutions between montmorillonite and nontronite were readily observable. Detections of hematite and zeolites suggested paleosols were affected by burial reddening and zeolitization, but absence of illite and chlorite suggest that potash metasomatism and other, more severe diagenetic alterations had not occurred. The high clay mineral content of the observed paleosols (up to 95 wt%) may have minimized diagenetic alteration over geological time scales. Martian paleosols rich in Al and Fe smectites may have also resisted severe diagenetic alteration, which is favorable for future in-situ examination. Results from this work can help differentiate paleosols and weathering profiles from other types of sedimentary rocks in the geological record of Mars.

Pyrolysis of sulfuric acid-treated chrome-tanned leather wastes: Kinetics, mechanism and evolved gas analysis

Management and safe disposal of chrome-tanned leather wastes generated in leather industry are of great importance due to their potential health risks and environmental hazards. Herein, an integrated strategy was proposed for disposing of chrome-tanned leather scrap (CTLS). This method involves the separation of chromium salts from CTLS with sulfuric acid for recycling purpose, followed by pyrolysis of the acid-treated CTLS in an inert atmosphere. SEM/EDX analysis was employed to characterize the changes in composition and morphology of CTLS after acid treatment. CO2 and H2O are main pyrolysis gases of CTLS, while the acid treatment increases the relative content of aliphatic hydrocarbons and NH3 in evolved gases. The pyrolysis characteristics and kinetics of the acid-treated CTLS were investigated by thermogravimetric analysis (TGA) at three different heating rates. After 3 and 6 days of acid treatment, the average activation energy of CTLS (450.9 kJ/mol) obtained from the Flynn-Wall-Ozawa method decreased to 369.6 and 351.0 kJ/mol, respectively. It is assumed that the CTLS consists of two pseudocomponents: low-crosslinked collagen (LCol) and highly-crosslinked collagen (HCol). Using the generalized master plots method, random nucleation and nuclei growth model (An model) was found to be the most probable kinetic model for the pyrolysis process of LCol and HCol. The kinetic exponent for pseudocomponent pyrolysis varied between 3.00 and 3.90, and the pre-exponential factor ranged from 5.83 × 1012 to 2.93 × 1013 min−1. The results of the present study provide an alternative route and useful information for recycling and disposing of chrome-containing leather wastes.

Experimental and numerical analysis of jet penetration and gas evolution in a single-nozzle distributor fluidized bed

This paper studies the injection of gas in a stagnant solid bed via a horizontal nozzle from experimental and theoretical perspectives, with the analysis of permanent jet plumes and subsequent bubble detachment. Advanced 3D X-Ray imaging techniques have been developed and used to observe the phenomenon, as well as to quantify important process parameters (gas distribution, jet length, bubble size, etc.). The experimental results are compared with those obtained from three-dimensional computational fluid dynamics (CFD) simulations of a gas-solid fluidized bed with primary air injection performed through a two-orifice horizontal nozzle. The proposed model correctly predicts the jet penetration at all the jet velocities tested. Uneven distribution of air through the cross-section of the bed is also observed, with the presence of the same two distinct regions experimentally observed, namely a fluidized core region and a compacted peripheral region. However, the model fails in predicting jets interaction and curvature due to asynchronous bubble detachment from the jets. This study demonstrates the usefulness of X-ray radiography in noninvasively visualising detailed internal features of industrial fluidized beds, thus providing an excellent benchmark to challenge the assumptions made in computational and theoretical models.

Microwave co-pyrolysis of kitchen food waste and rice straw for waste reduction and sustainable biohydrogen production: Thermo-kinetic analysis and evolved gas analysis

Physico-chemical characteristics of kitchen food waste (KFW) and rice straw (RS) were explored to determine the optimum feedstock ratio for biohydrogen production. An in-depth investigation on the thermogravimetric degradation was conducted at heating rates of 10, 20, and 30 ℃/min. Friedman, Kissinger-Akahira-Sunose, and Flynn-Wall-Ozawa iso-conversional techniques were applied to investigate the kinetic properties of different mass ratios of the feedstocks. The average apparent activation energy (Ea) increased for all co-pyrolysis blends, reaching a maximum for 75KFW blend samples (138.6911 kJ/mol for Friedman, 136.9028 kJ/mol for KAS, and 146.5558 kJ/mol for FWO). The relatively small difference between ΔH and Ea indicated the production feasibility of the reactions. A microwave reactor was used to investigate product yields for different blend proportions. Gas chromatography analysis showed that co-pyrolysis improved production of biohydrogen, with 25KFW attaining a maximum yield of 43.02%. Overall, this study reflects the viability of scaled-up KFW and RS co-pyrolysis as a waste management alternative and an effective and sustainable source of biohydrogen.

Synthesis of Decorated Carbon Structures with Encapsulated Components by Low-Voltage Electric Discharge Treatment

Polycondensation of complexes of chloromethanes with triphenylphosphine by the action of low-voltage electric discharges in the liquid phase gives nanosized solid products. The elemental composition involving the generation of element distribution maps (scanning electron microscopy–energy dispersive X‑ray spectroscopy mapping) and the component composition (by direct evolved gas analysis–mass spectrometry) of the solid products have been studied. The elemental and component compositions of the result-ing structures vary widely depending on the chlorine content in the substrate and on the amount of triphenylphosphine taken. Thermal desorption analysis revealed abnormal behavior of HCl and benzene present in the solid products. In thermal desorption spectra, these components appear at an uncharacteristically high temperature. The observed anomaly in the behavior of HCl is due to HCl binding into a complex of the solid anion {text{HCl}}_{2}^{ - } with triphenyl(chloromethyl)phosphonium chloride, which requires a relatively high temperature (up to 800 K) to decompose. The abnormal behavior of benzene is associated with its encapsulated state in nanostructures. The appearance of benzene begins at 650 K and continues up to temperatures above 1300 K.

Acidic wood extractives accelerate the curing process of emulsion polymer isocyanate adhesives

AbstractEmulsion polymer isocyanate (EPI) adhesive is one of the most widely used structural adhesives in the woodworking industry. However, there has been a lack of knowledge on how the EPI‐adhesive interacts with the chemical constituents of wood, in particular, with the wood extractives that are known to influence the bonding quality. In this study, the interactions of the EPI‐adhesive with the water extracts and selected extractives from European wood species were systematically investigated using different analytical techniques. While the alterations in the curing properties of the pure EPI‐adhesive and EPI‐adhesive‐extract mixtures were revealed by in situ rheology and Fourier‐transform infrared spectroscopy, evolved gas analysis, and pyrolysis‐gas chromatography/mass spectrometry, the solid‐state 13C nuclear magnetic resonance were performed for analyzing the final chemical composition of the cured adhesive. Moreover, the influence of the extraction on the mechanical bonding performance was tested by tensile‐shear tests. The study revealed significant interactions between the EPI‐adhesive and tannin‐rich, acidic wood extracts. The acidic chestnut and oak extracts catalyzed the curing reactions and led to a huge increase in the adhesive viscosity. These interactions might affect the bonding quality, for example, adhesive penetration depth and formation of bonding strength, therefore, careful attention is required when bonding acidic wood surfaces.

In-depth investigation of the exothermic reactions between lithiated graphite and electrolyte in lithium-ion battery

Thermal runaway is a critical issue for the large application of lithium-ion batteries. Exothermic reactions between lithiated graphite and electrolyte play a crucial role in the thermal runaway of lithium-ion batteries. However, the role of each component in the electrolyte during the exothermic reactions with lithiated graphite has not been fully understood. In this paper, the exothermic reactions between lithiated graphite and electrolyte of lithium-ion battery are investigated through differential scanning calorimetry (DSC) and evolved gas analysis. The lithiated graphite in the presence of electrolyte exhibit three exothermic peaks during DSC test. The reactions between lithiated graphite and LiPF6 and ethylene carbonate are found to be responsible for the first two exothermic peaks, while the third exothermic peak is attributed to the reaction between lithiated graphite and binder. In contrast, diethylene carbonate and ethyl methyl carbonate contribute little to the total heat generation of graphite-electrolyte reactions. The reaction mechanism between lithiated graphite and electrolyte, including the major reaction equations and gas products, are summarized. Finally, DSC tests on samples with various amounts of electrolyte are performed to clarify the quantitative relationship between lithiated graphite and electrolyte during the exothermic reactions. 2.5 mg of lithiated graphite (Li0.8627C6) can fully react with around 7.2 mg electrolyte, releasing a heat generation of 2491 J g−1. The results presented in this study can provide useful guidance for the safety improvement of lithium-ion batteries.

Thermal analysis of MgFe-Cl Layered doubled hydroxide (LDH) directly synthetized and produced \u201cvia memory effect\u201d

Layered doubled hydroxides (LDHs) are known to be an interesting class of 2D layered materials, with a wide range of possible composition and a flexible structure suitable for topochemical reactions. Thus, LDHs have been applying in different fields, such as catalysis, energy storage and all the applications in which a high exchange capability (of both cations and anions) is required. For remediation purpose, a MgFe-Cl LDH {[({mathrm{Mg}}_{0.66}^{2+}{mathrm{Fe}}_{0.33}^{3+}{left(mathrm{OH}right)}_{2}]}^{0.33+}{({mathrm{Cl}}_{0.33}^{-})}^{0.33-} (MFC in the following) could be a promising candidate to capture the toxic CrO42− from water, in exchange with the Cl− in an efficient way. The synthesis of this compound might seem simple, consisting of a coprecipitation reaction, and actually, it is strongly affected by the environmental carbon dioxide able to replace the Cl− with the more stable CO32−. To avoid this problem, LDHs could be also prepared with a rehydration of their calcinated oxide (memory effect). In this work were prepared two samples of MFC: one via coprecipitation (MFC-1 in the following) and one via “memory effect” (MFC-mem in the following). Both the compounds were characterized by means of X-ray powder diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR) and differential thermal analysis-thermogravimetry (DTA-TG) coupled with evolved gas analysis. The results demonstrated that the synthesis of pure MFC is very difficult, and only a minimum contamination of carbon dioxide led to the formation of the carbonate LDH in a massive way. It was also demonstrated that Mg-Fe LDHs in the presence of carbonate could catalyse the formation of the formic acid (HCOOH) at low temperature (< 300 °C).

Depleted carbon isotope compositions observed at Gale crater, Mars

Obtaining carbon isotopic information for organic carbon from Martian sediments has long been a goal of planetary science, as it has the potential to elucidate the origin of such carbon and aspects of Martian carbon cycling. Carbon isotopic values (δ13CVPDB) of the methane released during pyrolysis of 24 powder samples at Gale crater, Mars, show a high degree of variation (-137 ± 8‰ to +22 ± 10‰) when measured by the tunable laser spectrometer portion of the Sample Analysis at Mars instrument suite during evolved gas analysis. Included in these data are 10 measured δ13C values less than -70‰ found for six different sampling locations, all potentially associated with a possible paleosurface. There are multiple plausible explanations for the anomalously depleted 13C observed in evolved methane, but no single explanation can be accepted without further research. Three possible explanations are the photolysis of biological methane released from the subsurface, photoreduction of atmospheric CO2, and deposition of cosmic dust during passage through a galactic molecular cloud. All three of these scenarios are unconventional, unlike processes common on Earth.

Textural and Thermal Properties of the Novel Fucoidan/Nano-Oxides Hybrid Materials with Cosmetic, Pharmaceutical and Environmental Potential.

The main purpose of the research was to obtain and study hybrid materials based on three different nano-oxides commonly used in the cosmetic and pharmaceutical industries: Al2O3, TiO2, and ZnO, with the natural bioactive polysaccharide fucoidan. Since the mentioned oxides are largely utilized by industry, there is no doubt that the presented studies are important from an environmental point of view. On the basis of the textural studies (dynamic light scattering DLS, low temperature nitrogen adsorption, X-ray diffraction analysis XRD, scanning electron microscopy SEM) it was proved that the properties of the hybrid materials differ from the pure components of the system. Moreover, the advanced thermal analysis (TG-DTG-DSC) combined with the evolved gas analysis using Fourier transformed infrared spectroscopy (FTIR) and mass spectrometry were applied to describe the thermal decomposition of fucoidan, oxides and hybrid materials. It was found that the interactions between the polymer and the oxides results in the formation of the hybrid materials due to the functionalization of the nanoparticles surface, and that their thermal stability increased when compared to the pure substrates. Such findings definitely fill the literature void regarding the fucoidan based hybrid materials and help the industrial formulators in the preparation of new products.

Conversion kinetics during melting of simulated nuclear waste glass feeds measured by dissolution of silica

We experimentally investigated the batch-to-glass conversion kinetics of two low-activity and two high-level nuclear waste melter feeds that represent widely different behavior during melting; tests comprised thermogravimetric analysis, the feed expansion test, evolved gas analysis, and x-ray diffraction. Our study indicates that the conversion processes, which include gas-evolving reactions, dissolution of crystalline phases, and primary foam expansion and collapse, are interconnected and influenced by the feed's thermal history. The fraction of dissolved silica was adopted as a measure of the extent of conversion inside the cold cap—the floating layer of feed material on the top surface of the melt in an electric melter. The interface between the cold cap and the free-flowing melt below was associated with a constant fraction of dissolved silica. The estimated viscosity of glass-forming melt at this interface lies within a narrow range for the feeds studied.

Investigation of the chemical changes during the thermal treatment of acrylonitrile‐co‐methyl acrylate‐polymer (polyacrylonitrile‐precursor) focusing on the fate of the methyl acrylate moiety

AbstractSeventeen samples of acrylonitrile (AN)‐co‐methyl acrylate (MA)‐polymer (MA content 0–11 mol%) are examined. Several selective isotopic labelings are employed (d1‐MA, d2‐MA, 13CO‐MA, CD3‐MA, d1‐AN, d2‐AN, and 15N‐AN). The thermal treatment under inert atmosphere is investigated to gain insight into the chemical transformation mechanisms concerning the MA sub‐unit. The volatiles are determined by means of evolved gas analysis (EGA) (Fourier transform infrared [FTIR] and GC/MS). Methanol is found for the first time as one decisive volatile stemming from the MA sub‐unit, next to water and carbon dioxide. In addition, methylamines are proven to be formed by reaction of ammonia with the MA sub‐unit, while a similar reaction of hydrogen cyanide (HCN) yielding in acetonitrile could be ruled out. Several volatile compounds could even be quantified. The non‐volatile polymeric material is characterized by means of simultaneous thermal analysis (differential scanning calorimetry, thermogravimetric analysis), in‐situ‐FTIR spectroscopy and sophisticated solid‐state NMR methods. Selected defined model compounds are synthesized and analyzed for comparison. Detailed reaction mechanisms for the thermal transformation are concluded from the results, pointing in particular to the importance of ammonia for all processes as stoichiometric and/or catalytic reagent.

Physicochemical Analysis of the Particulate Matter Emitted from Road Vehicle Engines

Air pollution with particulate matter from transport sources is a serious problem in terms of air quality and its impact on human health. The article attempts to test the emitted particles from piston engines in terms of their physical properties and chemical composition. The research test objects were a diesel engine with Euro 5 emission class and a petrol engine, which was a part of the scooter drive system. The conducted research consisted in the analysis of the number, mass, and volume of particles, as well as chemical analysis, using the methods: Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope with Energy Dispersive Spectroscopy (SEM-EDS), and Evolved gas analysis (EGA). The diesel engine emitted particles in the range of 50–120 nm. With the increase in the engine load, the specific emission of particulate matter increased. In the case of a gasoline engine running without load, the emission of particles smaller than 30 nm was mainly observed. Increasing load of the gasoline engine resulted in an increase in both the concentration of particles and their diameter (average diameter to 90 nm). FTIR analysis showed higher black carbon content in the case of the sample taken from the diesel engine. In order to carry out a more detailed chemical analysis, the EGA and SEM methods were used. On their basis, the chemical composition of particles was presented, and a greater ability to agglomerate of a gasoline engine particles was found.