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Garvey CJ, Impéror-Clerc M, Rouzière S, Gouadec G, Boyron O, Rowenczyk L, Mingotaud AF, Ter Halle A. Molecular-Scale Understanding of the Embrittlement in Polyethylene Ocean Debris. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:11173-11181. [PMID: 32808772 DOI: 10.1021/acs.est.0c02095] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The fate of plastic waste is a pressing issue since it forms a visible and long-lived reminder of the environmental impact of consumer habits. In this study, we examine the structural changes in the lamellar arrangements of semicrystalline polyethylene (PE) packaging waste with the aim of understanding the physical mechanisms of embrittlement in PE exposed to the marine environment. PE microplastics and macroplastics from identifiable PE packaging were collected in the Atlantic Ocean and compared to new PE boxes. Several experimental techniques interrogate the effects of environmental exposure on their bulk and surface properties. Size exclusion chromatography determines the molecular weight distribution of the PE polymer chains and differential scanning calorimetry gives the crystallinity. Small- and wide-angle X-ray scattering examines the packing of PE chains into semicrystalline lamellae. Longitudinal acoustic mode Raman spectroscopy provides a complementary measurement of the length of PE polymer chains extending through the crystalline lamellar domains. While there is a high degree of uncertainty in the time scale for the changes, the overall picture at the molecular scale is that although PE becomes more crystalline with environmental exposure, the lamellar order present in new packing boxes is disrupted by the weathering process. This process has important implications for embrittlement and subsequent degradation.
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Affiliation(s)
- Christopher J Garvey
- Laboratoire de Physique des Solides, UMR 8502, CNRS, Université Paris Saclay, 91400 Orsay, France
- Lund Institute for Advanced Neutron and X-ray Science, 223 70 Lund, Sweden
- Biofilm-Research Center for Biointerfaces and Biomedical Science Department, Faculty of Health and Society, Malmö University, 211 19 Malmö, Sweden
- Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Marianne Impéror-Clerc
- Laboratoire de Physique des Solides, UMR 8502, CNRS, Université Paris Saclay, 91400 Orsay, France
| | - Stéphan Rouzière
- Laboratoire de Physique des Solides, UMR 8502, CNRS, Université Paris Saclay, 91400 Orsay, France
| | - Gwenaël Gouadec
- Laboratoire MONARIS, Sorbonne Université, CNRS, c49, 75252 Paris, France
| | - Olivier Boyron
- C2P2-LCPP Group, UMR CNRS 5265, Université de Lyon, ESCPE Lyon, Bat 308F, 43 Bd du 11 novembre 1918, 69616 Villeurbanne, France
| | - Laura Rowenczyk
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Paul Sabatier, 118, route de Narbonne, F-31062 Toulouse, Cedex 09, France
| | - Anne Françoise Mingotaud
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Paul Sabatier, 118, route de Narbonne, F-31062 Toulouse, Cedex 09, France
| | - Alexandra Ter Halle
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Paul Sabatier, 118, route de Narbonne, F-31062 Toulouse, Cedex 09, France
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Samuel AZ. Direct estimation of polymer crystallinity with Raman spectroscopy using ratio of scattering cross-sections estimated from variable temperature measurements. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 224:117431. [PMID: 31376726 DOI: 10.1016/j.saa.2019.117431] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 07/23/2019] [Accepted: 07/26/2019] [Indexed: 06/10/2023]
Abstract
Physical properties of polymers (e.g. crystallinity, lamella thickness, thermodynamic properties etc.) can in principle be reliably estimated from their Raman spectral intensities by converting intensities to corresponding concentrations of conformers. However, such conversions are not straightforward due to the unknown scattering cross-sections. The study demonstrates that for several practical applications of Raman spectroscopy, a ratio of cross-sections can be used instead of the absolute values. A straight forwards method for accurately estimating ratio of scattering cross-section from variable temperature measurements is described here. In order to demonstrate its applicability, percent crystallinity (PC) of polyethylene has been directly estimated from Raman intensities without external calibration with other techniques. This general method can be applied to any polymer when there is a continuous change in composition of conformers over a range of temperatures.
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Affiliation(s)
- Ashok Zachariah Samuel
- Research Organization for Nano and Life Innovations, Waseda University, Shinjuku-ku, Tokyo, Japan.
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