Raman and ATR-FTIR unmask crystallinity changes and carboxylate group and vinyl group accumulation in natural weathering polypropylene microplastics
Abstract Naturally weathered polypropylene (NWPP) samples are useful for investigating the effects of various degradation factors that cannot be obtained in artificial laboratory experiments. In this study, NWPP samples were extracted from beach sediments (Ashiya, Hyogo, Japan). Raman and attenuated...
Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2025-01-01
|
| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-025-85837-y |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1832585830977241088 |
|---|---|
| author | Raihan Anshari Motohiro Tsuboi Harumi Sato Kohji Tashiro Yukihiro Ozaki |
| author_facet | Raihan Anshari Motohiro Tsuboi Harumi Sato Kohji Tashiro Yukihiro Ozaki |
| author_sort | Raihan Anshari |
| collection | DOAJ |
| description | Abstract Naturally weathered polypropylene (NWPP) samples are useful for investigating the effects of various degradation factors that cannot be obtained in artificial laboratory experiments. In this study, NWPP samples were extracted from beach sediments (Ashiya, Hyogo, Japan). Raman and attenuated total reflection (ATR)–Fourier-transform infrared (FTIR) spectroscopies were used to analyze variations in the composition, crystallinity, orientation, and degradation of NWPP microplastics. The degree of degradation varies from sample to sample, from position to position in a sample, and the inside surface or outside surface of a sample. Significant intensity variations were observed for Raman bands at 1150 and 842 cm⁻¹, indicating changes in the crystallinity and molecular orientation of NWPP due to degradation. The Raman spectra of the elongated pristine PP showed intensity increases at 1150, 998, and 842 cm−1, indicating variations in the molecular orientation of the polymer chains induced by elongation. The ATR-FTIR spectra of NWPP yield several major new features in the 3600 –3200 cm−1 (OH stretching), 1750–1500 cm−1 (C=O/C=C/COO− stretching), and 1150–900 cm−1 (C–O/C–C stretching) regions. Of particular note is that in the 1750–1500 cm−1 region, at least four bands due to two kinds of vinyl groups and two kinds of carboxylate groups are clearly observed in the second derivative spectra, while bands arising from carbonyl compounds are weak. This may be the first time that the carboxylate bands have ever appeared more strongly than the carbonyl bands in the IR spectra of NWPP. The appearance of the carboxylate bands indicates two possibilities: one is the effect of seawater on the degradation of NWPP samples, and another is the oxidation of keto groups to the carboxylates. Moreover, since a few kinds of vinyl compounds and carboxylates are produced, it is very likely that the degree of degradation is high in the NWPP samples. In this way, IR spectroscopy is useful for exploring the degradation of NWPP while Raman spectroscopy is effective for examining variations in their crystallinity and orientation. |
| format | Article |
| id | doaj-art-219801efadfb495c99a690e3d9b89113 |
| institution | Kabale University |
| issn | 2045-2322 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj-art-219801efadfb495c99a690e3d9b891132025-01-26T12:24:55ZengNature PortfolioScientific Reports2045-23222025-01-0115111510.1038/s41598-025-85837-yRaman and ATR-FTIR unmask crystallinity changes and carboxylate group and vinyl group accumulation in natural weathering polypropylene microplasticsRaihan Anshari0Motohiro Tsuboi1Harumi Sato2Kohji Tashiro3Yukihiro Ozaki4Department of Applied Chemistry for Environment, Graduate School of Science and Technology, Kwansei Gakuin UniversityDepartment of Applied Chemistry for Environment, Graduate School of Science and Technology, Kwansei Gakuin UniversityGraduate School of Human Development and Environment, Kobe UniversityAichi Synchrotron Radiation CenterDepartment of Biomedical Sciences, Graduate School of Science and Technology, Kwansei Gakuin UniversityAbstract Naturally weathered polypropylene (NWPP) samples are useful for investigating the effects of various degradation factors that cannot be obtained in artificial laboratory experiments. In this study, NWPP samples were extracted from beach sediments (Ashiya, Hyogo, Japan). Raman and attenuated total reflection (ATR)–Fourier-transform infrared (FTIR) spectroscopies were used to analyze variations in the composition, crystallinity, orientation, and degradation of NWPP microplastics. The degree of degradation varies from sample to sample, from position to position in a sample, and the inside surface or outside surface of a sample. Significant intensity variations were observed for Raman bands at 1150 and 842 cm⁻¹, indicating changes in the crystallinity and molecular orientation of NWPP due to degradation. The Raman spectra of the elongated pristine PP showed intensity increases at 1150, 998, and 842 cm−1, indicating variations in the molecular orientation of the polymer chains induced by elongation. The ATR-FTIR spectra of NWPP yield several major new features in the 3600 –3200 cm−1 (OH stretching), 1750–1500 cm−1 (C=O/C=C/COO− stretching), and 1150–900 cm−1 (C–O/C–C stretching) regions. Of particular note is that in the 1750–1500 cm−1 region, at least four bands due to two kinds of vinyl groups and two kinds of carboxylate groups are clearly observed in the second derivative spectra, while bands arising from carbonyl compounds are weak. This may be the first time that the carboxylate bands have ever appeared more strongly than the carbonyl bands in the IR spectra of NWPP. The appearance of the carboxylate bands indicates two possibilities: one is the effect of seawater on the degradation of NWPP samples, and another is the oxidation of keto groups to the carboxylates. Moreover, since a few kinds of vinyl compounds and carboxylates are produced, it is very likely that the degree of degradation is high in the NWPP samples. In this way, IR spectroscopy is useful for exploring the degradation of NWPP while Raman spectroscopy is effective for examining variations in their crystallinity and orientation.https://doi.org/10.1038/s41598-025-85837-y |
| spellingShingle | Raihan Anshari Motohiro Tsuboi Harumi Sato Kohji Tashiro Yukihiro Ozaki Raman and ATR-FTIR unmask crystallinity changes and carboxylate group and vinyl group accumulation in natural weathering polypropylene microplastics Scientific Reports |
| title | Raman and ATR-FTIR unmask crystallinity changes and carboxylate group and vinyl group accumulation in natural weathering polypropylene microplastics |
| title_full | Raman and ATR-FTIR unmask crystallinity changes and carboxylate group and vinyl group accumulation in natural weathering polypropylene microplastics |
| title_fullStr | Raman and ATR-FTIR unmask crystallinity changes and carboxylate group and vinyl group accumulation in natural weathering polypropylene microplastics |
| title_full_unstemmed | Raman and ATR-FTIR unmask crystallinity changes and carboxylate group and vinyl group accumulation in natural weathering polypropylene microplastics |
| title_short | Raman and ATR-FTIR unmask crystallinity changes and carboxylate group and vinyl group accumulation in natural weathering polypropylene microplastics |
| title_sort | raman and atr ftir unmask crystallinity changes and carboxylate group and vinyl group accumulation in natural weathering polypropylene microplastics |
| url | https://doi.org/10.1038/s41598-025-85837-y |
| work_keys_str_mv | AT raihananshari ramanandatrftirunmaskcrystallinitychangesandcarboxylategroupandvinylgroupaccumulationinnaturalweatheringpolypropylenemicroplastics AT motohirotsuboi ramanandatrftirunmaskcrystallinitychangesandcarboxylategroupandvinylgroupaccumulationinnaturalweatheringpolypropylenemicroplastics AT harumisato ramanandatrftirunmaskcrystallinitychangesandcarboxylategroupandvinylgroupaccumulationinnaturalweatheringpolypropylenemicroplastics AT kohjitashiro ramanandatrftirunmaskcrystallinitychangesandcarboxylategroupandvinylgroupaccumulationinnaturalweatheringpolypropylenemicroplastics AT yukihiroozaki ramanandatrftirunmaskcrystallinitychangesandcarboxylategroupandvinylgroupaccumulationinnaturalweatheringpolypropylenemicroplastics |