Evolution of Polymer Melt Conformation and Entanglement under High-Rate Elongational Flow  

作　　者：Jia-Peng Zhang Li-Cheng Ma Yong-Jin Ruan Yu-Yuan Lu Li-Jia An 

机构地区：[1]State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun,130022,China [2]School of Applied Chemistry and Engineering,University of Science and Technology of China,Hefei,230026,China

出　　处：《Chinese Journal of Polymer Science》2024年第12期2021-2029,I0012,共10页高分子科学（英文版）

基　　金：supported by the National Key R&D Program of China(Nos.2020YFA0713601 and 2023YFA1008800);the National Natural Science Foundation of China(Nos.22341304,22341303,22103079 and 22073092);the Cooperation Project between Jilin Province and CAS(No.2023SYHZ0003).

摘　　要：Using molecular dynamics(MD)simulations,this study explores the fluid properties of three polymer melts with the same number of entanglements,Z,achieved by adjusting the entanglement length Ne,while investigating the evolution of polymer melt conformation and entanglement under high-rate elongational flow.The identification of a master curve indicates consistent normalized linear viscoelastic behavior.Surprising findings regarding the steady-state viscosity at various elongational rates(Wi_(R)>4.7)for polymer melts with the same Z have been uncovered,challenging existing tube models.Nevertheless,the study demonstrates the potential for normalizing the steady-state elongational viscosity at high rates(Wi_(R)>4.7)by scaling with the square of the chain contour length.Additionally,the observed independence of viscosity on the elongational rate at high rates suggests that higher rates lead to a more significant alignment of polymer chains,a decrease in entanglement,and a stretching in contour length of polymer chains.Molecular-level tracking of tagged chains further supports the assumption of no entanglement under rapid elongation,emphasizing the need for further research on disentanglement in polymer melts subjected to high-rate elongational flow.These results carry significant implications for understanding and predicting the behavior of polymer melts under high-rate elongational flow conditions.

关 键 词：Polymer rheology High-rate elongational flow Entangled polymer melts Molecular dynamics simulations DISENTANGLEMENT 

分 类 号：TQ317[化学工程—高聚物工业]