The effect of weathering environments on microplastic chemical identification with Raman and IR spectroscopy: Part I. polyethylene and polypropylene

Phan, Samantha; Padilla‐Gamiño, Jacqueline L.; Luscombe, Christine K.

doi:10.1016/j.polymertesting.2022.107752

Cited by 60 publications

(18 citation statements)

References 75 publications

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“…The region at 1000–1200 cm − 1 is attributed to the stretching vibration absorptions of the C-O (around 1160 cm −1 ), indicating different C-O-containing degradation products but may also indicate phosphate ions, bonds of the glycosidic linkages [ 52 ], or aliphatic phosphates. It is interesting to observe the presence of similar peaks (from 1162 to 1035 cm −1 ) in previous work [ 51 ] that, comparing the ageing of particles suspended in different matrices (deionized water, artificial seawater, natural seawater, air), detected new unique products in the particles weathered in the natural seawater.…”

Section: Discussionsupporting

confidence: 54%

“…The diversity in hydroxyl band intensity is possibly due to the non-homogenous weathering that occurs on the particles related to their different source of origin; otherwise, it could be a result of exfoliation and flaking of the plastic surface. Previous research also detected changes in this absorption area in particles aged under artificial conditions and observed more marked peaks in samples weathered in water than compared to those in the air [ 51 ].…”

Section: Discussionmentioning

confidence: 96%

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Fourier Transform Infrared Spectroscopy to Assess the Degree of Alteration of Artificially Aged and Environmentally Weathered Microplastics

et al. 2023

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Fourier transform infrared (FTIR) is a spectroscopy technique widely used to identify organic materials. It has recently gained popularity in microplastic (MP) pollution research to determine the chemical composition of unknown plastic fragments. However, it could also be used to evaluate the degree of ageing of MPs collected from the environment. In this context, the principal aim of our research has been to qualitatively evaluate the natural weathering of environmental MPs collected in an Italian freshwater body (the Ofanto River) using ATR-FTIR technology. Furthermore, we compared environmental particles to weathered artificial MPs under controlled light and temperature conditions and to unaltered pristine materials to assess the results. FTIR spectra were acquired using a Nicolet Summit FTIR (ThermoFisher Scientific) equipped with an Everest ATR with a diamond Crystal plate and a DTGS KBr detector (wavenumber range 4000–500 cm−1, 32 scans per spectrum, spectral resolution of 4 cm−1). The degree of ageing was assessed using three different indexes known to be related to changes in MPs: Carbonyl Index (CI), Hydroxyl Index (HI), and Carbon-Oxygen Index (COI). The overall results showed that the regions reflecting changes (hydroxyl groups, peaks from 3100 to 3700 cm−1, alkenes or carbon double bonds, 1600 and 1680 cm−1, and carbonyl groups, 1690 and 1810 cm−1) appeared significantly modified in artificial and natural weathered particles compared to the pristine materials. The indexes calculated for polymers degraded under the artificial photo and thermo ageing conditions displayed a general tendency to increase with the time in contact with irradiation time. Particular enhancements of CI of PS fragment and PE pellet, HI of PE and PS fragments and PE pellet, and COI of PS fragment were observed. Otherwise, the following incubation of the same particles at a constant temperature of 45 °C did not further affect the chemical composition of the particles. Moreover, new unique peaks were also observed in the freshwater particles, almost all in the fingerprint region (1500–500 cm−1). Differences in CI, HI, and COI were evidenced among the different morphological MP shapes. On the one hand, the CI calculated for the environmental PE pellets showed values ranging from 0.05 to 0.26 with a mean value of 0.17 ± 0.10. Most samples (57%) presented a CI with values between 0.16 and 0.30. On the other hand, fragments presented slicer modifications in the carbonyl region with CI values lower than pellets (0.05 ± 0.05). This index helps evaluate the degradation of PE MPs by UV light, increasing with enhancing residence time in the environment. Conversely, fragments showed greater values of HI (5.90 ± 2.57) and COI (1.04 ± 0.48) than pellets, as well as lines, which presented the maximum value of HI (11.51). HI is attributed to the bond vibrations of hydroxyl, carboxyl, or phenol groups. In contrast, COI is frequently attributed to the vibrations of C_O bonds found in carbohydrates, alkanes, secondary alcohols, and ketones. In conclusion, our results showed characteristics spectra acquired from environmental particles compared to pristine and artificial aged ones. The interpretation of our main results emphasizes the need to conduct ecotoxicological experimental studies using naturally weathered particles due to the unicity of their properties, which are more helpful for understanding microplastic pollution effects.

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Section: Discussionsupporting

confidence: 54%

Section: Discussionmentioning

confidence: 96%

Fourier Transform Infrared Spectroscopy to Assess the Degree of Alteration of Artificially Aged and Environmentally Weathered Microplastics

et al. 2023

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“…Hence, RT-FTIR spectroscopy is often combined with other techniques in so-called combined techniques, i.e. , rheological measurements, 100–102 dielectric analysis (DEA), 103–106 fluorescence spectroscopy, 107–110 photocalorimetry (DSC), 111–113 thermogravimetry (TGA) and others. 114–117…”

Section: Quantitative Methods For Monitoring Photopolymerization Reac...mentioning

confidence: 99%

“…[95][96][97][98][99] Therefore, this method is only applicable to thin films, so when using RT-FTIR, it is not possible to obtain information, e.g., about the kinetics of rheological changes in the composition, changes in volume due to the expansion or contraction of the polymer network or changes in crosslinking density along with the sample thickness profile. Hence, RT-FTIR spectroscopy is often combined with other techniques in so-called combined techniques, i.e., rheological measurements, [100][101][102] dielectric analysis (DEA), [103][104][105][106] fluorescence spectroscopy, [107][108][109][110] photocalorimetry (DSC), [111][112][113] thermogravimetry (TGA) and others. [114][115][116][117] ATR-FTIR (attenuated total reflectance Fourier-transform infrared) spectroscopy has also been utilized to successfully examine the conversion of the reaction and composition during polymerization monitoring.…”

Section: Fourier-transform Real-time Infrared Spectroscopy (Rt-ftir)mentioning

confidence: 99%

Review of quantitative and qualitative methods for monitoring photopolymerization reactions

et al. 2023

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“…This feature is significant if photo-oxidation occurs when the polymers are in water or marine water [ 1 , 2 , 3 ]. The degradation of polymers in sea water is of remarkable importance due to the dramatic consequences that the fragmentation of plastics into microplastics has on the marine environment [ 4 , 5 , 6 , 7 ]. The seawater plays some protective role in the photo-oxidation of polymers, and the lower photo-oxidation kinetic in water, and marine water in particular, compared to photo-oxidation in the air has been attributed to the low oxygen concentration in marine water [ 8 , 9 , 10 , 11 , 12 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

Influence of Different Environments and Temperatures on the Photo-Oxidation Behaviour of the Polypropylene

et al. 2022

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The photo-oxidation of polypropylene at two different temperatures and in three different environments—air, distilled water and sea water—has been followed as a function of the irradiation time. The photo-oxidation kinetic is dramatically dependent on the amount of oxygen available for the oxidation reactions and on the temperature. While the photo-oxidation is very fast in air, the degradation is much slower in the two aqueous media. The degradation in sea water is slightly slower than in distilled water. In all cases, the degradation kinetic increases remarkably with the temperature. This behavior has been attributed to the lower oxygen availability for the oxidation reactions of the polymers. The light difference of the degradation kinetic between the two aqueous media depends on the small difference of the oxygen concentration at the test temperatures of 40 and 70 °C. At the latter temperature, the difference between the degradation kinetic in distilled water and sea water is still less important because increasing the temperature decreases the solubility of the oxygen, and it tends to became very similar in both samples of water.

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The effect of weathering environments on microplastic chemical identification with Raman and IR spectroscopy: Part I. polyethylene and polypropylene

Cited by 60 publications

References 75 publications

Fourier Transform Infrared Spectroscopy to Assess the Degree of Alteration of Artificially Aged and Environmentally Weathered Microplastics

Fourier Transform Infrared Spectroscopy to Assess the Degree of Alteration of Artificially Aged and Environmentally Weathered Microplastics

Review of quantitative and qualitative methods for monitoring photopolymerization reactions

Influence of Different Environments and Temperatures on the Photo-Oxidation Behaviour of the Polypropylene

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