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Cai M, He X, Liu B. Revealing the Effect of the Molecular Weight Distribution on the Chain Diffusion and Crystallization Process under a Branched Trimodal Polyethylene System. Polymers (Basel) 2024; 16:265. [PMID: 38257063 PMCID: PMC10818820 DOI: 10.3390/polym16020265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/15/2024] [Accepted: 01/15/2024] [Indexed: 01/24/2024] Open
Abstract
With the increasing demand for high-end materials, trimodal polyethylene (PE) has become a research hotspot in recent years due to its superior performance compared with bimodal PE. By means of molecular dynamics (MD) simulations, we aim to expound the effect of the molecular weight distribution (MWD) on the mechanism of nucleation and crystallization of trimodal PE. The crystallization rate is faster when short-chain branching is distributed on a single backbone compared to that on two backbones. In addition, as the content of high molecular weight backbone decreases, the time required for nucleation decreases, but the crystallization rate slows down. This is because low molecular weight backbones undergo intra-chain nucleation and crystallize earlier due to the high diffusion capacity, which leads to entanglement that prevents the movement of medium or high molecular weight backbones. Furthermore, crystallized short backbones hinder the movement and crystallization of other backbones. What is more, a small increase in the high molecular weight branched backbone of trimodal PE can make the crystallinity greater than that of bimodal PE, but when the content of high molecular weight backbone is too high, the crystallinity decreases instead, because the contribution of short and medium backbones to high crystallinity is greater than that of long backbones.
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Affiliation(s)
- Min Cai
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Meilong Road 130, Shanghai 200237, China;
| | - Xuelian He
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Meilong Road 130, Shanghai 200237, China;
| | - Boping Liu
- College of Materials and Energy, South China Agricultural University, Guangzhou 510642, China
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2
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Wu Z, Wu JW, Michaudel Q, Jayaraman A. Investigating the Hydrogen Bond-Induced Self-Assembly of Polysulfamides Using Molecular Simulations and Experiments. Macromolecules 2023; 56:5033-5049. [PMID: 38362140 PMCID: PMC10865372 DOI: 10.1021/acs.macromol.3c01093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 06/08/2023] [Indexed: 02/17/2024]
Abstract
In this paper, we present a synergistic, experimental, and computational study of the self-assembly of N,N'-disubstituted polysulfamides driven by hydrogen bonds (H-bonds) between the H-bonding donor and acceptor groups present in repeating sulfamides as a function of the structural design of the polysulfamide backbone. We developed a coarse-grained (CG) polysulfamide model that captures the directionality of H-bonds between the sulfamide groups and used this model in molecular dynamics (MD) simulations to study the self-assembly of these polymers in implicit solvent. The CGMD approach was validated by reproducing experimentally observed trends in the extent of crystallinity for three polysulfamides synthesized with aliphatic and/or aromatic repeating units. After validation of our CGMD approach, we computationally predicted the effect of repeat unit bulkiness, length, and uniformity of segment lengths in the polymers on the extent of orientational and positional order among the self-assembled polysulfamide chains, providing key design principles for tuning the extent of crystallinity in polysulfamides in experiments. Those computational predictions were then experimentally tested through the synthesis and characterization of polysulfamide architectures.
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Affiliation(s)
- Zijie Wu
- Department
of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy St., Newark, Delaware 19716, United States
| | - Jiun Wei Wu
- Department
of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Quentin Michaudel
- Department
of Chemistry, Texas A&M University, College Station, Texas 77843, United States
- Department
of Materials Science & Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Arthi Jayaraman
- Department
of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy St., Newark, Delaware 19716, United States
- Department
of Materials Science and Engineering, University
of Delaware, 201 DuPont Hall, Newark, Delaware 19716, United States
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3
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Cooling-Rate Computer Simulations for the Description of Crystallization of Organic Phase-Change Materials. Int J Mol Sci 2022; 23:ijms232314576. [PMID: 36498903 PMCID: PMC9737975 DOI: 10.3390/ijms232314576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 11/17/2022] [Accepted: 11/20/2022] [Indexed: 11/24/2022] Open
Abstract
A molecular-level insight into phase transformations is in great demand for many molecular systems. It can be gained through computer simulations in which cooling is applied to a system at a constant rate. However, the impact of the cooling rate on the crystallization process is largely unknown. To this end, here we performed atomic-scale molecular dynamics simulations of organic phase-change materials (paraffins), in which the cooling rate was varied over four orders of magnitude. Our computational results clearly show that a certain threshold (1.2 × 1011 K/min) in the values of cooling rates exists. When cooling is slower than the threshold, the simulations qualitatively reproduce an experimentally observed abrupt change in the temperature dependence of the density, enthalpy, and thermal conductivity of paraffins upon crystallization. Beyond this threshold, when cooling is too fast, the paraffin's properties in simulations start to deviate considerably from experimental data: the faster the cooling, the larger part of the system is trapped in the supercooled liquid state. Thus, a proper choice of a cooling rate is of tremendous importance in computer simulations of organic phase-change materials, which are of great promise for use in domestic heat storage devices.
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4
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Stretching-induced Nucleation and Crystallization of Cyclic Polyethylene: Insights from Molecular Dynamics Simulation. Eur Polym J 2022. [DOI: 10.1016/j.eurpolymj.2022.111232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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5
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Sheng J, Chen W, Cui K, Li L. Polymer crystallization under external flow. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:036601. [PMID: 35060493 DOI: 10.1088/1361-6633/ac4d92] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 01/20/2022] [Indexed: 06/14/2023]
Abstract
The general aspects of polymer crystallization under external flow, i.e., flow-induced crystallization (FIC) from fundamental theoretical background to multi-scale characterization and modeling results are presented. FIC is crucial for modern polymer processing, such as blowing, casting, and injection modeling, as two-third of daily-used polymers is crystalline, and nearly all of them need to be processed before final applications. For academics, the FIC is intrinsically far from equilibrium, where the polymer crystallization behavior is different from that in quiescent conditions. The continuous investigation of crystallization contributes to a better understanding on the general non-equilibrium ordering in condensed physics. In the current review, the general theories related to polymer nucleation under flow (FIN) were summarized first as a preliminary knowledge. Various theories and models, i.e., coil-stretch transition and entropy reduction model, are briefly presented together with the modified versions. Subsequently, the multi-step ordering process of FIC is discussed in detail, including chain extension, conformational ordering, density fluctuation, and final perfection of the polymer crystalline. These achievements for a thorough understanding of the fundamental basis of FIC benefit from the development of various hyphenated rheometer, i.e., rheo-optical spectroscopy, rheo-IR, and rheo-x-ray scattering. The selected experimental results are introduced to present efforts on elucidating the multi-step and hierarchical structure transition during FIC. Then, the multi-scale modeling methods are summarized, including micro/meso scale simulation and macroscopic continuum modeling. At last, we briefly describe our personal opinions related to the future directions of this field, aiming to ultimately establish the unified theory of FIC and promote building of the more applicable models in the polymer processing.
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Affiliation(s)
- Junfang Sheng
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Wei Chen
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Kunpeng Cui
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Liangbin Li
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, People's Republic of China
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6
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Cao Y, Zhao L, Wang J, Shao Y, He X. Molecular dynamics simulation of extension-induced crystallization of branched bimodal HDPE: Unraveling the effects of short-chain branches. Phys Chem Chem Phys 2021; 23:19862-19871. [PMID: 34525133 DOI: 10.1039/d1cp01067k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bimodal HDPE models were designed for extension-induced crystallization imitating the architecture of industrial bimodal HDPE copolymerized with ethylene and 1-butene, 1-hexene, or 1-octene. Crystallites of bimodal HDPE experienced the emergence of precursors, shish nuclei, and lamellae. The compact conformation of branched polymers impeded the rolling-over, deposition, and folding of chains on the substrate, and thus the formation of nuclei and lamella. Moreover, this retardation was intensified with the rising branch density and length, causing a depression of crystallinity and an increment of tie-chains concentration. Besides, when branches were all located on long chains, the compact conformation enlarged the resistance to the disentanglement of main chains, thus relatively fewer branched long chains were involved in the precursors or nuclei, resulting in the attenuation of lamella formation. Furthermore, for ethyl branched polymers, the coexistent orthorhombic and monoclinic crystallites were built up, and a few expanded monoclinic cells occurred for butyl branches because of the larger butyl reeling into lamella, while hexagonal crystals were created for ethyl/1-hexyl copolymers because of cocrystallization. Additionally, relative to ethyl, larger butyl and hexyl were preferential to be repelled outside crystals to form tie-chains, and hexyl branched polymers acquired relatively fewer tie-chains because of hexagonal eutectoid.
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Affiliation(s)
- Yiran Cao
- Shanghai Key Laboratory of Multiphase Material Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Li Zhao
- Shanghai Key Laboratory of Multiphase Material Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Jieqi Wang
- Shanghai Key Laboratory of Multiphase Material Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Yunqi Shao
- Shanghai Key Laboratory of Multiphase Material Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Xuelian He
- Shanghai Key Laboratory of Multiphase Material Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
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7
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Chen W, Ren Y. Molecular dynamics simulations of polymerisation and crystallisation at constant chemical potential. MOLECULAR SIMULATION 2020. [DOI: 10.1080/08927022.2020.1776276] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Wei Chen
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Ying Ren
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, People's Republic of China
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8
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Hu Y, Shao Y, Liu Z, He X, Liu B. Dominant Effects of Short-Chain Branching on the Initial Stage of Nucleation and Formation of Tie Chains for Bimodal Polyethylene as Revealed by Molecular Dynamics Simulation. Polymers (Basel) 2019; 11:E1840. [PMID: 31717356 PMCID: PMC6918436 DOI: 10.3390/polym11111840] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/01/2019] [Accepted: 11/05/2019] [Indexed: 11/21/2022] Open
Abstract
The molecular mechanism of short-chain branching (SCB), especially the effects of methylene sequence length (MSL) and short-chain branching distribution (SCBD) on the initial stage of nucleation, the crystallization process, and particularly the tie chain formation process of bimodal polyethylene (BPE), were explored using molecular dynamics simulation. This work constructed two kinds of BPE models in accordance with commercial BPE pipe resins: SCB incorporated in the long chain or in the short chains. The initial stage of nucleation was determined by the MSL of the system, as the critical MSL for a branched chain to nucleate is about 60 CH2. SCB incorporated in the long chain led to a delay of the initial stage of nucleation relative to the case of SCB incorporated in the short chains. The increase of branch length could accelerate the delay to nucleation. The location of short chain relative to the long chain depended on the MSL of the short chain. As the MSL of the system decreased, the crystallinity decreased, while the tie chains concentration increased. The tie chains concentration of the BPE model with branches incorporated in the long chain was higher than that with branches incorporated in the short chain.
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Affiliation(s)
- Yanling Hu
- Shanghai Key Laboratory of Multiphase Material Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China; (Y.H.); (Y.S.); (Z.L.)
| | - Yunqi Shao
- Shanghai Key Laboratory of Multiphase Material Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China; (Y.H.); (Y.S.); (Z.L.)
| | - Zhen Liu
- Shanghai Key Laboratory of Multiphase Material Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China; (Y.H.); (Y.S.); (Z.L.)
| | - Xuelian He
- Shanghai Key Laboratory of Multiphase Material Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China; (Y.H.); (Y.S.); (Z.L.)
| | - Boping Liu
- College of Materials and Energy, South China Agricultural University, Guangzhou 510642, China
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9
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Anwar M, Graham RS. Molecular dynamics simulations of crystal nucleation in entangled polymer melts under start-up shear conditions. J Chem Phys 2019; 150:084905. [DOI: 10.1063/1.5082244] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Muhammad Anwar
- School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Richard S. Graham
- School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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10
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Hu Y, Shao Y, Liu Z, He X, Liu B. Effect of short-chain branching on the tie chains and dynamics of bimodal polyethylene: Molecular dynamics simulation. Eur Polym J 2018. [DOI: 10.1016/j.eurpolymj.2018.01.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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11
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12
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Luo C, Kröger M, Sommer JU. Entanglements and Crystallization of Concentrated Polymer Solutions: Molecular Dynamics Simulations. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b02124] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chuanfu Luo
- Leibniz-Institut
für Polymerforschung Dresden e.V., Hohe Strasse 6, 01069 Dresden, Germany
- Max Planck Institute
of Colloids and Interfaces, Am Mühlenberg
1, 14476 Potsdam, Germany
| | - Martin Kröger
- Polymer
Physics, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Jens-Uwe Sommer
- Leibniz-Institut
für Polymerforschung Dresden e.V., Hohe Strasse 6, 01069 Dresden, Germany
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13
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Yamamoto T. Molecular dynamics of crystallization in n-alkane mixtures; texture, compatibility, and diffusion in crystals. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.07.089] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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14
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Gao R, He X, Shao Y, Hu Y, Zhang H, Liu Z, Liu B. Effects of Branch Content and Branch Length on Polyethylene Crystallization: Molecular Dynamics Simulation. MACROMOL THEOR SIMUL 2016. [DOI: 10.1002/mats.201500089] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Rui Gao
- State Key Laboratory of Chemical Engineering; East China University of Science and Technology; 130 Meilong Road Shanghai 200237 P. R. China
| | - Xuelian He
- State Key Laboratory of Chemical Engineering; East China University of Science and Technology; 130 Meilong Road Shanghai 200237 P. R. China
| | - Yunqi Shao
- State Key Laboratory of Chemical Engineering; East China University of Science and Technology; 130 Meilong Road Shanghai 200237 P. R. China
| | - Yanling Hu
- State Key Laboratory of Chemical Engineering; East China University of Science and Technology; 130 Meilong Road Shanghai 200237 P. R. China
| | - Haiyang Zhang
- State Key Laboratory of Chemical Engineering; East China University of Science and Technology; 130 Meilong Road Shanghai 200237 P. R. China
| | - Zhen Liu
- State Key Laboratory of Chemical Engineering; East China University of Science and Technology; 130 Meilong Road Shanghai 200237 P. R. China
| | - Boping Liu
- State Key Laboratory of Chemical Engineering; East China University of Science and Technology; 130 Meilong Road Shanghai 200237 P. R. China
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15
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Gao R, He X, Zhang H, Shao Y, Liu Z, Liu B. Molecular dynamics study of the isothermal crystallization mechanism of polyethylene chain: the combined effects of chain length and temperature. J Mol Model 2016; 22:67. [PMID: 26932477 DOI: 10.1007/s00894-016-2931-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 02/04/2016] [Indexed: 10/22/2022]
Abstract
A molecular level understanding of the polyethylene (PE) crystallization process was elucidated by molecular dynamics simulation of three states, with varying chain length and temperature. The process can be classified into the following three states: (1) nucleation controlled state, (2) competitive state of crystal growth process and new nuclei formation, and (3) crystal growth controlled state, which could be quantified by the evolution of nuclei number. With increasing chain length, two phenomena occur: the single crystallization mechanism changes from state (1) to (3), and the crystal size increases while the b/a axial ratio in the lateral surface decreases. These changes can be explained from a thermodynamic point of view, in that the van der Waals (vdW) interaction per CH2 unit is strengthened and more nucleation sites are generated for longer chain. Size effect (meaning different surface fractions when the chain collapses into a globule) was an important factor determining vdW energy per unit and the crystallization states of a single PE chain. On the other hand, the crystallization states were independent of chain length for short chains systems with the same size effect. In both conditions, a long chain generates multi-crystal domains, and a short chain prefers a single crystal domain. Our results not only provide molecular level evidence for crystallization states but also clarify the influence of chain length on the crystallization process.
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Affiliation(s)
- Rui Gao
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China.
| | - Xuelian He
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China.
| | - Haiyang Zhang
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China.
| | - Yunqi Shao
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China.
| | - Zhen Liu
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China.
| | - Boping Liu
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China.
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16
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Anwar M, Schilling T. Crystallization of polyethylene: A molecular dynamics simulation study of the nucleation and growth mechanisms. POLYMER 2015. [DOI: 10.1016/j.polymer.2015.08.041] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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17
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Wang J, Zhu X, Lu X, Zhou Z, Wang G. On structures and properties of polyethylene during heating and cooling processes based on molecular dynamics simulations. COMPUT THEOR CHEM 2015. [DOI: 10.1016/j.comptc.2014.11.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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18
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Anwar M, Berryman JT, Schilling T. Crystal nucleation mechanism in melts of short polymer chains under quiescent conditions and under shear flow. J Chem Phys 2014; 141:124910. [DOI: 10.1063/1.4896568] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Muhammad Anwar
- Theory of Soft Condensed Matter Physics, Physics and Materials Research Unit, Université du Luxembourg, L-1511 Luxembourg, Luxembourg
| | - Joshua T. Berryman
- Theory of Soft Condensed Matter Physics, Physics and Materials Research Unit, Université du Luxembourg, L-1511 Luxembourg, Luxembourg
| | - Tanja Schilling
- Theory of Soft Condensed Matter Physics, Physics and Materials Research Unit, Université du Luxembourg, L-1511 Luxembourg, Luxembourg
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