( 您好!臺灣時間:2023/09/29 11:38
字體大小: 字級放大   字級縮小   預設字形  
回查詢結果 :::


研究生(外文):Yung-Hong Yen
論文名稱(外文):Molecular Dynamics Simulation of the Orientation of Polymer Chains in Weld Line Region
指導教授(外文):Rong-Yeu Chang
外文關鍵詞:Molecular Dynamics Simulationweld linepolymer orientation
  • 被引用被引用:0
  • 點閱點閱:169
  • 評分評分:
  • 下載下載:0
  • 收藏至我的研究室書目清單書目收藏:0
本研究主要利用分子動力學模擬(Molecular Dynamics simulation)分析探討在高分子加工過程中,當兩流動波前相遇時所產生之縫合線(Weld-Line)介面間,高分子鏈流動排向的行為及相互融合的結果。以分子動力學模擬描述在不同溫度下,縫合線兩邊高分子鏈排列以及相互擴散之排向結果。
本論文首先比照文獻探討hexadecane流體分子(C16H34)於Couette shear flow系統下,壁面性質與剪切率對滑動程度的影響;結果發現當代表壁面與流體交互作用強度的εw增大時,流體與壁面間的滑動現象將會減低,然而壁面粗糙度的增加更能夠有效減少滑動的程度;另外,隨著剪切率增加,滑動的程度則是提昇的。

In this study, the orientation behavior of polymer chains in weld-line region, which usually occurs in polymer processing when two melt fronts combine together, is simulated by molecular dynamics. Simulation is carried out at different temperature to show polymer chains arrangement and their inter-diffusion in the weld interface.
The first part of this work is to simulate thin films of hexadecane (C16H34) fluid under Couette shear flow. The analysis results about slip boundary phenomena according to different wall properties and shear rates are demonstrated to be in good agreement with references. As the wall roughness or εw increase, the degree of slip will be reduced.On the other hand, larger shear rates cause more slip between fluids and wall. We also show that the fluid velocity profile is not affected by different lattice arrangement.
As to simulation of weld-line, the fluid molecule used is C25H52. Based on the results, the orientation in z-direction, which is perpendiculato the flow direction, is observed to concentrate in the weld-line region formed by two melt fronts. As temperature increases, polymer chains diffuse more into each other, and the z-direction orientation is eliminated.

中文摘要 I
Abstract II
目錄 III
圖目錄 VI
表目錄 X
符號表 XI
第一章、緒論 1
1-1研究目的與動機 1
1-2縫合線與分子鏈結構 3
1-3分子動力學模擬 7
1-3-1分子動力學模擬概論 7
1-3-2分子動力學模擬方法簡介 8
1-3-3 Lennard-Jones Potential 9
1-3-4 NVT系統簡介 10
1-3-5分子動力學與連續力學 13
第二章、文獻回顧 15
2-1簡單分子流動行為 15
2-2高分子鏈結晶排向行為 18
2-3 高分子流動系統 23
第三章、研究方法 28
3-1基本方法分析 28
3-1-1交互作用力形式 28
3-1-2壁面原子與晶格 29
3-1-3邊界條件 30
3-1-4起始條件 31
3-1-5 Orientation factor 32
3-1-6 Thermostat 33
3-2數值方法… 34
3-2-1 Cell link neighbor list 34
3-2-2運動方程式求解 35
3-3模擬流程… 38
3-3-1 Couette shear flow 38
3-3-2縫合線排向 41
第四章、結果與討論 43
4-1 Couette shear flow 43
4-1-1系統初始條件與參數設定 43
4-1-2壁面原子之kw對流速及滑動的影響 43
4-1-3εw對流速及滑動的影響 44
4-1-4剪切率對流速及滑動的影響 44
4-1-5壁面晶格排列對流速及滑動的影響 49
4-2縫合線排向及擴散行為(1) 51
4-2-1系統初始條件 51
4-2-2排向結果 51
4-2-4結果討論(1) 59
4-3縫合線排向及擴散行為(2) 60
4-3-1系統設定 60
4-3-2波前結合 61
4-3-3分子鏈擴散結果 63
4-3-4波前結合處排向性結果 68
4-3-5結果與討論(2) 72
第五章、結論與展望 73
參考文獻 74

1. 張榮語,“射出成型模具設計-操作實務”,高立圖書有限公司,1995.
2. 周彥博,“以分子動力學探討孔穴流之行為”,碩士論文,中原大學,2000.
3. Kevin R. Quinn. James A. Duffy, Chris S. Ellis,“understanding weld-line integrity”, LNP ENGINEERING PLASTICS.
4. “Injection Molding”, ME495 LaboratoryⅡ-IM-1, Michigan Engineering.
5. Maxwell A.,“Practical Guide for Designers and Manufacturers of Mouldings to Reduce the Risk of Environment Stress Cracking”, Moulders Guide v3.doc, NPL Report MATC(A) 05, March 2001.
6. Barkhudarov M.R. and Hirt C.W.,“TRACKING DEFECTS”, Flow Science, Inc.,1998.
7. Hrishikesh Kharbas, Lih-Sheng Turng, Rick Spindler, and Brian Burhop,“STUDY OF WELD-LINE STRENGTH AND MICROSTRUCTURE OF INJECTION MOLDED MICROCELLULAR PARTS”, Paper Draft for SPE ANTEC 2002.
8. Welp K.A.,“Determining the Correct Polymer Dynamics Model for Thermoplastic Welding”, Center for Composite Materials, University of Delaware, Research of Poster, 1998.
9. Jarrod J. Schemenauer“Investigation of Weld-Line Performance in Injection-Molded Natural Fiber-Thermoplastic Composites”, BIOGRAPHIES AND ABSTRACTS, 1999.
10. HAILE J.M.,“MOLECULAR DYNAMICS SIMULATION-Elementary Methods”, 1997.
11. Nosé, S.,“A unified formulation of the constant temperature molecular dynamics methods”, J. Chem. Phy., 81, pp.511-519, 1984.
12. William G. Hoover,“Canonical dynamics: Equilibrium phase-space distributions”, Physical Review A. 31, pp.1695-1697, 1985.
13. Andersen, H. C.,“Molecular dynamics at constant pressure and/or temperature”, Journal of Chemical Physics, 81, pp.2384-2393, 1980.
14. Thompson Peter A. and Robbins M.O.,“Simulation of Contact-Line Motion: Slip and the Dynamics Contact Angle”, Physical Review Letters 63, p.766, 1989.
15. Thompson Peter A. and Robbins M.O.,“Shear flow near solids: Epitaxial order and flow boundary conditions”, Physical Review E. 41, pp.6830-6837, June 1999.
16. Ju LI, Donguy Liao, and Sidney Yip,“Coupling continuum to molecular-dynamics simulation: Reflecting particle method and the field estimator”, Physical Review E. 57, pp.7359-7367, June 1999.
17. Susumu Fujiwara and Tetsuya Sato,“Molecular dynamics simulations of structural formation of a single polymer chain: Bond-orientational order and conformational defects”, Journal of Chemical Physics, 107, pp.613-622, July 1997.
18. Mayo S.L., Olafson B.D., and Goddard Ⅲ W.A., Journal of Physical Chemistry 94, p.8897, 1990.
19. Susumu Fujiwara and Tetsuya Sato,“Molecular Dynamics Simulation of Structural Formation of Short Polymer Chains”, Physical Reivew Letters 80, pp.991-994, February 1998.
20. Susumu Fujiwara and Tetsuya Sato,“Molecular Dynamics Simulation of Structural Formation of Short Polymer Chains”, Journal of Chemical Physics, 110, pp.9757-9764, May 1999.
21. Moore J.D., Cui S.T., Cochran H.D., Cummings P.T.,“A molecular dynamics study of a short-chain polyethylene melt. Ⅰ. Steady-state shear”, Journal of Non-Newtonian Fluid Mechanics, 93, pp.83-99, 2000.
22. Moore J.D., Cui S.T., Cochran H.D., Cummings P.T.,“A molecular dynamics study of a short-chain polyethylene melt. Ⅱ. Transient response upon onset of shear”, Journal of Non-Newtonian Fluid Mechanics. 93, pp.101-116, 2000.
23. Hiroyasu Tasaki, Jun-ichi Takimoto, Masao Doi,“Prediction of the rheological properties of polymers using a stochastic simulation”, Computer Physics Communications 142, pp.136-139, 2001.
24. Jabbazadeh A., Atkinson J.D., Tanner R.I., “Nanorheology of molecularly thin films of n-hexadecane in Couette shear flow by molecular dynamics”, Journal of Non-Newtonian Fluid Mechanics, 77, pp. 53-78, 1998.
25. Jabbazadeh A., Atkinson J.D., Tanner R.I.,“Wall slip in the molecular dynamics simulation of thin films of hexadecane ”, Journal of Chemical Physics, 110, pp. 2612-2620, 1999.
26. Gupta S.A., Cochran H.D., Cumming P.T.,“Shear behavior of squalane and tetracosane under extreme confinement.1: Model, simulation method, and interfacial slip”, Journal of Chemical Physics., 107, pp.10316-10326, 1999.
27. Gear C.W.,“Numerical Initial Value Problems in Ordinary Differential Equations”, Prentice-Hall, Englewood Cliffs, NJ, Chap. 9, 1971.
28. Broughton, J., W. Krakow, and S.T. Pantelides, Eds.,“A Theoretical Perspective of Dynamics, Structure, and Thermodynamics”, 71 of Adv. Chem. Phys.,Wiley, New York, 1988.
29. Susumu Fujiwara and Tetsuya Sato, “Molecular dynamics simulation of a single polymer chain in vacuum and in solution”, Computer Physics Communication, 147, pp.342-345, 2002.
30. Marc S. Lavin, Numan Waheed, Gregory C. Rutledge, “Molecular dynamics simulation of orientation and crystallization of polyethylene during uniaxial extension”, Polymer 44, pp. 1771-1779, 2002.
31. Jae Youn Lee, Arlette R.C. Baljon, and Roger F. Loring, “Simulation of polymer melt interaction in layered nonocomposites”, Journal of Chemical Physics, 23, pp. 10321-10330, 1998.
32. Rajesh Khare, Juan de Pablo, Arun Yethiraj, “Molecular simulation and continuum mechanics study of simple fluid in non-isothermal planar couette flows”, Journal of Chemical Physics, 107, pp. 2589-2596, 1997.

第一頁 上一頁 下一頁 最後一頁 top