Molecular dynamic simulations of deformation behaviour of blended polyethylene

Abstract

ABSTRACTThe tensile deformation behaviour of blended polyethylene (PE) was studied using molecular dynamic methods. The blended PE was modeled by blending linear chains with different molecular weights based on a united atom model. The mechanical response and microscopic conformational behaviours of blended PE were investigated at different strain rates and temperatures. The interatomic energy evolution displayed a similar trend to the stress–strain curve showing the stiffness of blended PE increase with a higher fraction of chain with high molecular weight. The microstructure metrics associated with free volume, orientation, entanglement and crystallisation were recorded as a function of strain in detail to obtain insight into the role of PE chains with different molecular weights for blended PE during deformation. The conformation evolution indicates that orientation and disentanglement are more noticeable in the short chain with low molecular weight in a blended PE system, while the long chain promotes the crystallisation of the initial chain structure. The chain entanglement evolution clearly shows some new flexion nodes created to entangle short chains again, implying that re-entanglement might exist during the tensile deformation.KEYWORDS: Molecular dynamic simulationsblended polyethylenedeformation behaviour AcknowledgementsThe present work is supported by the Advanced Research Project of Manned Spaceflight under Grant Nos. 040101, and Science Foundation of the National Key Laboratory of Science and Technology on Advanced Composites in Special Environments.Disclosure statementNo potential conflict of interest was reported by the author(s).CRediT authorship contribution statementJingfu Shi: Conceptualisation, Methodology, Software, Formal analysis, Investigation, Writing – original draft. Jia Zhou: Validation, Investigation, Writing – review & editing. Lei Liu: Visualisation, Writing – review & editing. Wenxiang Liu: Writing – review & editing. Changqing Miao: Writing – review & editing, Supervision, Project administration, Funding acquisition.Declaration of competing interestThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.