Precursor formation and crystal nucleation in stretched polyethylene/carbon nanotube nanocomposites

• Published in: Polymer (Guilford) Vol. 239; p. 124438
• Main Authors: Nie, Yijing, Yang, Jun, Liu, Zongfa, Zhou, Zhiping, Ming, Yongqiang, Hao, Tongfan
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 17.01.2022; Elsevier BV
• Subjects: Addition polymerization; Carbon; Carbon nanotubes; Conformation; Crystallites; Crystallization; Crystals; Entropy; Molecular dynamics; Molecular dynamics simulations; Nanocomposites; Nucleation; Orientation; Polyethylene; Polyethylenes; Polymer nanocomposites; Polymers; Precursors; Reduction; Segments; Stretching; Theoretical analysis; Polymer nanocomposites; Nucleation; Molecular dynamics simulations
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2021.124438

Based on molecular dynamics simulations, we focused on the stretch-induced precursor formation and nucleation process in carbon nanotube (CNT) filled polyethylene. During stretching, in addition to polymer segments, CNTs can also orient along the stretching direction. In this condition, the segments in interfacial regions are subject to two orientation effects: CNT-induced segment orientation and stretch-induced segment orientation, which then can exhibit higher degree of orientation and higher content of segments with trans-conformation, compared with the segments in non-interfacial regions. Finally, these interfacial segments are easier to evolve into precursors and oriented crystallites. Based on the theoretical analysis, it was demonstrated that the crystallization rate at the early stage of crystallization is codetermined by the difference in the nucleation modes (homogeneous nucleation or heterogeneous nucleation), the stretch-induced conformational entropy reduction and the orientation entropy reduction. [Display omitted] •Molecular simulations of stretch-induced crystallization of PE nanocomposites.•CNTs promote segment orientation, conformational change and precursor formation.•Nucleation was determined by nucleation modes, conformational entropy reduction and orientation entropy reduction.