Ordering and Crystallization of Entangled Polyethylene Melts under Uniaxial Tension: A Molecular Dynamics Study
| Autor: | Joseph L. Lenhart, Jan Andzelm, Martin Kröger, Kevin A. Masser, Yelena R. Sliozberg, In-Chul Yeh |
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| Rok vydání: | 2018 |
| Předmět: |
chemistry.chemical_classification
Void (astronomy) Materials science Polymers and Plastics Organic Chemistry Nucleation 02 engineering and technology Polymer Strain rate Polyethylene 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences law.invention Inorganic Chemistry Crystallinity chemistry.chemical_compound Molecular dynamics chemistry law Chemical physics Materials Chemistry Crystallization 0210 nano-technology |
| Zdroj: | Macromolecules, 51 (23) |
| ISSN: | 1520-5835 0024-9297 |
| DOI: | 10.1021/acs.macromol.8b01538 |
| Popis: | Morphological and mechanical properties of semicrystalline polymers are strongly influenced by flow-induced crystallization during processing. We perform extensive molecular dynamics simulations with more than 1 million atoms to describe orientation, drawability, and crystallization of entangled polyethylene melts under uniaxial tensions at three different strain rates and after a subsequent cooling. During tensile deformation at the lowest strain rate of 107 s–1, the polyethylene melt experiences entanglement loss and crystal nucleation. At higher strain rates of 108 and 109 s–1, we observe a higher degree of chain alignment and void formation in addition to disentanglement and crystal nucleation. Chain segments make sharp turns relative to the neighboring chain orientations at the entanglement points, which manifests as a bimodal distribution of the local order parameter. Upon cooling below the melting temperature, semicrystalline polyethylene with a crystallinity close to 50% is formed. The entanglemen... |
| Databáze: | OpenAIRE |
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