Filtern
Erscheinungsjahr
Dokumenttyp
- Zeitschriftenartikel (85)
- Vortrag (67)
- Beitrag zu einem Sammelband (12)
- Beitrag zu einem Tagungsband (11)
- Posterpräsentation (4)
- Buchkapitel (1)
- Dissertation (1)
- Sonstiges (1)
Schlagworte
- Mikroplastik (32)
- Microplastics (22)
- Analytik (15)
- TED-GC-MS (14)
- Fire retardancy (12)
- Microplastic (12)
- Flame retardancy (9)
- Analysis (8)
- Pyrolysis (8)
- Flame retardance (7)
Organisationseinheit der BAM
- 6 Materialchemie (47)
- 6.6 Physik und chemische Analytik der Polymere (47)
- 1 Analytische Chemie; Referenzmaterialien (8)
- 5 Werkstofftechnik (6)
- 5.3 Polymere Verbundwerkstoffe (6)
- 1.4 Prozessanalytik (4)
- 1.7 Organische Spuren- und Lebensmittelanalytik (4)
- 4 Material und Umwelt (2)
- 4.3 Schadstofftransfer und Umwelttechnologien (2)
- 7 Bauwerkssicherheit (2)
Paper des Monats
- ja (2)
Eingeladener Vortrag
- nein (67)
A first pilot study on the sorption of environmental pollutants on various microplastic materials
(2017)
With the drastic increase in plastic production, the input of plastic particles into the environment has become a recognised problem.
Xenobiotics are able to sorb to polymer materials, and this process is further enhanced where they Encounter microplastics (plastic fragments <5 mm). In this work we studied the sorption of metformin, a type-2 diabetes drug, and difenoconazole, a fungicide, onto the virgin polymer materials polyamide (PA), polypropylene (PP), and polystyrene (PS). Additionally, PP was cryo-milled and PA was treated with acid to investigate the influence of an increase in surface area and chemical modification. The material properties were also studied by dynamic scanning calorimetry (DSC), gel permeation chromatography (GPC) and Fourier transform infrared spectroscopy (FTIR). Sorption experiments were performed on the basis of a full factorial design examining the effect of agitation, pH value, and salinity. Experimental results showed that difenoconazole sorbs readily to all microplastics, whereas the more polar analyte metformin did not show any affinity to the materials used. For difenoconazole the governing factor in all cases is agitation, while both pH and salinity exhibited only a slight influence. The modification of polymers leads to enhanced sorption, indicating that an increase in surface area (cryo-milled PP) or inner volume (acid-treated PA) strongly favours adsorption. Moreover, long-term experiments demonstrated that the time until equilibrium is reached depends strongly on the particle size.
A new flame retardant based on an ammonium phosphonate is studied with respect to its thermal decomposition and its mode of action in wood-plastic composites (WPCs). The measurements are carried out by means of fire tests (cone calorimeter) and pyrolysis investigations (thermogravimetry, infrared spectroscopy). The flame retardant acts mainly in the condensed phase by increasing the amount of residue formed by the wood part in the WPC. Additional flame dilution is achieved by the release of water, ammonia and carbon dioxide during the decomposition of the flame retardant.
The thermal molecular degradation of polyamide 66 (PA 66) doped with (partially supported) metal oxide particles (Fe2O3, ZnO, Al2O3) was investigated qualitatively and quantitatively using common analysis techniques like thermogravimetry coupled with IR-spectroscopic evolved gas analysis (TGA-FTIR). Using pyrolysis coupled with gas chromatography mass spectrometry (Py-GC-MS), qualitative conclusions were drawn about the complex hydrocarbon products. However, the combination of TGA with solid-phase extraction, followed by thermal desorption gas chromatography mass spectrometry (TED-GC-MS), allows qualitative and even semi-quantitative conclusions about the decomposition pathway of PA 66 in the presence of various metal oxide particles.
The investigations under inert conditions showed that the presence of metal particles increases the rate of decarboxylation and deamination reactions, as well as the formation rate of cyclopentanone and pyridine derivatives. These species are a consequence of various condensation reactions. The condensation reactions release a large amount of water, thus triggering the hydrolysis of PA 66. Molecular thermal degradation mechanisms were developed for the main decomposition as well as for the condensation reactions and supported by quantum chemical calculations. The catalytic effect of the metal oxides in PA 66 increases in the following order: PA 66 = PA 66 – Al2O3 < PA 66 – Fe2O3 < PA 66 – ZnO.
Inputs of plastic impurities into the environment via the application of fertilizers are regulated in Germany and the EU by means of ordinances. Robust and fast analytical methods are the basis of legal regulations. Currently, only macro- and large microplastic contents (>1 mm) are measured. Microplastics (1–1,000 µm), are not yet monitored. Thermal analytical methods are suitable for this purpose, which can determine the mass content and can also be operated fully automatically in routine mode. Thermal extraction desorption-gas chromatography/mass spectrometry (TED-GC/MS) allows the identification of polymers and the determination of mass contents in solid samples from natural environments. In accordance with the German or European Commission (EC) Fertiliser Ordinance, composting plants should be monitored for microplastic particles with this method in the future. In this context a compost plant was sampled. At the end of the rotting process, the compost was sieved and separated in a coarse (>1 mm) and a fine fraction (<1 mm). The fine fraction was processed using density separation comparing NaCl and NaI as possible salt alternative and screened for microplastic masses by TED-GC/MS with additional validation and quality assurance experiments. With TED-GC/MS total microplastics mass contents of 1.1–3.0 μg/mg in finished compost could be detected with polyethylene mainly. What differs much to the total mass of plastics in the coarse fraction with up to 60 μg/mg, which were visually searched, identified via ATR-FTIR and gravimetrically weighted.
Due to the increasing presence of microplastic particles (MP) in the Environment and the unknown risks arising from them, there is an urgent need for analytical methods that allow for an efficient identification and quantification of microplastics (MP), i.e. particles < 5 mm, in environmental samples. So far, mostly timeconsuming (micro) infrared or micro-Raman spectroscopic methods are applied. Here an faster alternative Approach is presented based on a Raman processspectrometer with fiber-optical probes in combination with multivariate data analysis.
Two commercial polyethylene grades were exposed to water at elevated temperatures and enhanced oxygen pressure. To characterize their aging behavior laser-induced photoluminescence spectroscopy was applied. Additionally, aging characterization was performed by established methods such as tensile testing, infrared (IR) spectroscopy, high performance liquid chromatography (HPLC), differential scanning calorimetry (DSC) and UV–VIS spectroscopy. During the initial stages of aging, the overall concentration of phenolic antioxidants as well as oxidation onset temperatures decreased exponentially. Simultaneously, significant discoloration due to the formation of conjugated degradation products from phenolic antioxidants (e.g., quinone methides) was detected. After the consumption of antioxidants, photoluminescence started to grow continuously presumably due to the formation of photoluminescent unsaturated carbonyls. In the final stages of aging, embrittlement of the materials as characterized by the degradation of mechanical properties (i.e., loss in ductility) coincided with rising carbonyl index values as well as an increase in crystallinity due to chemicrystallization. Between integrated photoluminescence intensity and carbonyl index, a linear correlation was established. In the induction period, the photoluminescence method exhibited a significantly higher sensitivity to reflect aging induced material changes.
There is growing interest in quantifying microplastics in environmental samples. This application note presents a thermal extraction desorption-gas chromatography/mass spectrometry (TED-GC/MS) method that is well suited to automation and increased sample throughput. The method is also able to detect all particle sizes in the sample as long as the limit of detection (LOD) is reached and allows analysis of larger samples of 15 to 25 mg or more. Samples were decomposed by thermogravimetric analysis (TGA), and the gaseous decomposition products were trapped on a solid-phase sorbent, followed by thermal desorption‑gas chromatography/mass spectrometry (TD-GC/MS) using an Agilent 5977B GC/MSD coupled to an Agilent 7890B GC. Target microplastic particle (MP) polymers were identified in environmental samples including surface water, finished compost, house dust, and drinking water. Quantification of MP polymers in environmental samples provided LODs of 0.06 to 2.2 μg, allowing the detection of MPs in trace amounts with sample weights of up to 1 g. Method repeatability was adequate for reliable quantification with RSDs of approximately 6 to 12%.