scholarly journals Material Analysis and a Visual Guide of Degradation Phenomena in Historical Synthetic Polymers as Tools to Follow Ageing Processes in Industrial Heritage Collections

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 121
Author(s):  
Till Krieg ◽  
Cristian Mazzon ◽  
Elena Gómez-Sánchez
Keyword(s):  
Synthetic Polymers ◽  
Attenuated Total Reflection ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyrolysis Gas ◽  
Industrial Heritage ◽  
Visual Damage ◽  
Material Information ◽  
Underlying Processes ◽  
Heritage Collections

Identifying the most vulnerable plastics and monitoring their deterioration is one of the main problems within heritage collections with historical synthetic polymers. Gathering and interpreting data about material and degradation phenomena in a collection reveals its conservation needs. A systematic survey of the collection can help towards this purpose. Surveys aiming at inspecting and documenting damages rely on several tools in order to fulfill their purpose. Firstly, objective descriptions of the damages that may appear, and secondly, the means of acquiring and interpreting material information. To address these needs, this article presents (a) a visual damage catalogue of degradation phenomena in plastic and rubber materials, and (b) the implementation of Fourier-transform infrared spectroscopy (FTIR) and pyrolysis–gas chromatography–mass spectrometry (py-GCMS) for the identification of analytically challenging rubber materials and of blooming phenomena. The damage catalogue is based solely on visual and olfactory signs, so that the assessment is independent of possible causes of damages and underlying processes, with the purpose of allowing objectivity to prime over interpretation. The limitations of the use of FTIR in the identification of heavily compounded rubbers in museum surveys is highlighted, and examples are presented. The use of py-GCMS on these cases conveniently allowed the identification of the constituting monomers of several rubber materials where FTIR could not provide a univocal classification of the material present. The study of several cases of blooming allowed the identification of diverse compositions and origins, showing that the description of a degradation phenomenon is only the first step towards its understanding. Unveiling the nature of a particular case of blooming is particularly critical when conservation treatments, such as the removal of a (potentially protecting) layer, are planned. For this purpose, attenuated total reflection-FTIR (ATR-FTIR) as a surface technique was particularly useful.

scholarly journals Are agricultural plastic covers a source of plastic debris in soil? A first screening study

2021 ◽  
Author(s):  
Zacharias Steinmetz ◽  
Paul Löffler ◽  
Silvia Eichhöfer ◽  
Jan David ◽  
Katherine Muñoz ◽  
...  
Keyword(s):  
Attenuated Total Reflection ◽  
Gas Chromatography Mass Spectrometry ◽  
Short Term ◽  
Pyrolysis Gas ◽  
Wind Drift ◽  
Plastic Debris ◽  
Fine Soil ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Screening Study ◽  
External Sources

Abstract. Agricultural plastic covers made from polyethylene (PE) and polypropylene (PP) offer increased yields and an improved crop quality. However, such covers are suspected of partially breaking down into smaller debris and thereby contributing to soil pollution with microplastics. To scrutinize this, we randomly sampled 240 topsoil cores (0–5 cm) from eight fields covered with fleeces, perforated foils, and plastic mulches for less than two years. Samples from the field periphery (50 m perimeter) served as reference. Visual plastic debris > 2 mm was analyzed by Fourier transformed infrared spectroscopy with attenuated total reflection (FTIR–ATR). Smaller, soil-associated plastic debris was dispersed from 50 g of fine soil (≤ 2 mm) using sodium hexametaphosphate solution and density-separated with saturated NaCl solution. The collected PE, PP, and polystyrene (PS) debris was selectively dissolved in a mixture of 1,2,4-trichlorobenzene and p-xylene at 150 °C and quantified by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). We counted six PE and PS fragments > 2 mm in two out of eight fields. By contrast, Py-GC/MS analysis revealed PE, PP, and PS contents > 1 µg g−1 in seven fields (17 % of all samples). In three fields, PE levels of 3–35 µg g−1 were associated with the use of thinner and less durable perforated foils (40 µm thickness). This was slightly more pronounced at field edges where the plastic covers are turned and weighted down. By contrast, 50 µm thick PE films were not indicated to emit any plastic debris. PP contents of 5–10 µg g−1 were restricted to single observations in the field centers of three sites. On one site, we found expanded PS particles >2 mm that concurred with elevated PS levels (8–19 µg g−1) in the fine soil. Both PP and PS were distributed indistinctly across sites so that their source remained unresolved. In addition, the extent to which plastic contents of up to 7 µg g−1 in the field periphery of some sites were attributed to wind drift from the covered fields or from external sources needs to be investigated in future studies. Yet, our results suggest that the short-term use of thicker and more durable plastic covers should be preferred to limit plastic emissions and accumulation in soil.

scholarly journals Surface Chemical Changes of Sugar Maple Wood Induced by Thermo-Hygromechanical (THM) Treatment

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1946 ◽  
Author(s):  
Qilan Fu ◽  
Alain Cloutier ◽  
Aziz Laghdir ◽  
Tatjana Stevanovic
Keyword(s):  
Wood Surface ◽  
Sugar Maple ◽  
Chemical Properties ◽  
Attenuated Total Reflection ◽  
Gas Chromatography Mass Spectrometry ◽  
Surface Chemical ◽  
Densification Process ◽  
Pyrolysis Process ◽  
Pyrolysis Gas ◽  
Chemical Changes

The aim of this study was to investigate the effects of heat and steam on the chemical properties of thermo-hygromechanical (THM)-densified sugar maple wood. The THM densification process was performed at two different temperatures (180 °C and 200 °C) with and without steam. The functional groups, surface chemical composition and internal structure and components of the control and densified samples were investigated using attenuated total reflection Fourier transform infrared (ATR-FTIR), X-ray photoelectron (XPS) spectroscopy and pyrolysis gas chromatography-mass spectrometry (Py-GC/MS). The obtained results suggest that the THM densification treatment resulted in significant chemical changes on the wood surface. The results of the ATR-FTIR spectra confirmed the decomposition of hemicelluloses and the relative increase of cellulose and lignin contents on the wood surface. The Py-GC/MS and XPS results show an increase of the oxygen/carbon atomic (O/C) ratio, which indicated that chemical substances containing oxygenated functionality were formed through the densification process. The densification treatment favored the depolymerization of hemicelluloses and cellulose as indicated by an increased anhydrous sugar (levoglucosan) release during the pyrolysis process. Densification also facilitated the cleavage of the lignin side chains, resulting in increased phenyl units with short chains released during the pyrolysis process.

scholarly journals Analysis of paint traces to determine the ship responsible for a collision

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
H. Lee ◽  
D. Lee ◽  
J. M. Seo
Keyword(s):  
Electron Microscopy ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyrolysis Gas ◽  
X Ray ◽  
Pyrolysis Gas Chromatography ◽  
Ship Collision ◽  
Derivative Thermogravimetry ◽  
Scanning Electron

AbstractAlthough there have been many instances of ship collision at sea in recent times, not much research has been conducted on the topic. In this study, paint from an actual site of ship collision was collected and analyzed as evidence. The amount of evidence collected from the ships involved in the collision is either small or has inconsistent morphology. In addition, the contaminants and samples are often mixed in this evidence, making its analysis difficult. Paint traces of the damaged ship and the ship suspected to be responsible for the collision were compared through scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDS), attenuated total reflection–Fourier transform infrared spectroscopy (ATR–FTIR), thermogravimetry (TG) and derivative thermogravimetry (DTG), and pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS) analyses. The ship responsible for the collision could be identified by characterization and by performing a comparative analysis of the extracted paint. Among the methods used in this study, Py–GC/MS can sensitively analyze even similar paints, and identified styrene and phthalic anhydride as the most prominent components of the paint used as evidence. The results obtained can be used to investigate the evidence collected from collision sites and to determine the ship responsible for the collision.

scholarly journals Cheminformatics Applied to Analytical Pyrolysis of Lignocellulosic Materials

2021 ◽  
Author(s):  
Jorge Reyes-Rivera
Keyword(s):  
Chemical Composition ◽  
Plant Biomass ◽  
Polymeric Materials ◽  
Gas Chromatography Mass Spectrometry ◽  
Lignocellulosic Materials ◽  
Compound Identification ◽  
Analytical Pyrolysis ◽  
Pyrolysis Gas ◽  
Pyrolysis Gas Chromatography

Pyrolysis-Gas Chromatography/Mass Spectrometry has been used to characterize a wide variety of polymers. The main objective is to infer the attributes of materials in relation to their chemical composition. Applications of this technique include the development of new improved materials in the industry. Furthermore, due to the growing interest in biorefinery, it has been used to study plant biomass (lignocellulose) as a renewable energy source. This chapter describes a procedure for characterization and classification of polymeric materials using analytical pyrolysis and cheminformatics. Application of omics tools for spectral deconvolution/alignment and compound identification/annotation on the Py-GC/MS chromatograms is also described. Statistical noise is generated by production of numerous small uninformative compounds during pyrolysis. Such noise is reduced by cheminformatics here detailed and this facilitate the interpretation of results. Furthermore, some inferences made by comparison of the identified compounds to those annotated with a biological role in specialized databases are exemplified. This cheminformatic procedure has allowed to characterize in detail, and classify congruently, different lignocellulosic samples, even using different Py-GC/MS equipment. This method can also be applied to characterize other polymers, as well as to make inferences about their structure, function, resistance and health risk based on their chemical composition.

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