عوامل مؤثر بر فشردگی مولکولی و اثر آن بر خواص مکانیکی اپوکسی

نوع مقاله: گزارش

نویسندگان

1 دانشجو ارشد

2 مرکز تحقیقات علوم و تکنولوژی کامپوزیت

چکیده

اپوکسی پخت‌شده پلیمری گرماسخت با ساختار بی‌شکل است. ساختار فاز بی‌شکل، بازتابی از تاریخچه گرمایی مکانیکی پلیمر است. پارامترهای بسیاری در ساختار فاز بی‌شکل بر خواص فیزیکی و مکانیکی اثرگذارند. از پارامترهایی که کمتر مورد توجه قرار گرفته، فشردگی مولکولی است. هدف این مقاله، بررسی عوامل اثرگذار بر فشردگی مولکولی است که به تغییر خواص مکانیکی منجر می‌شود. اندازه‌گیری فشردگی مولکولی با پراش پرتو ایکس و تخمین تقریبی آن با استفاده از چگالی ماکروسکوپی و محاسبه جدایش بین‌زنجیری با استفاده از معادله براگ انجام می‌شود. همچنین، معادلات دیگری برای محاسبه میانگین جدایش بین‌زنجیری و اندازه بلور در سامانه‌های نیمه‌بلوری در این مقاله معرفی می‌شود. مطالعات نشان می‌دهند، وجود ساختارهای صلب در پیکره باعث افزایش تمایل به آرایش‌یافتگی می‌شود. افزون بر این، وجود شاخه کوچک‌تر از فضای آزاد بین‌زنجیری، افزایش فشردگی و خواص مکانیکی را به‌دنبال دارد. به‌طور کلی در اضافه‌کردن افزودنی به سامانه، با کاهش مقیاس اندازه ذره فشردگی سامانه بیشتر می‌شود. همچنین، وجود اصلاح‌کننده‌های سطحی روی ذرات، به‌ویژه نانوذرات، سبب آرایش ماتریس موجود در اطراف ذره می‌شود که افزایش فشردگی مولکولی و خواص مکانیکی را به‌دنبال دارد. افزودن نرم‌کننده به سامانه نیز در صورت جدایی فاز با بزرگ‌ترشدن مقدار فاز ناپیوسته، باعث کاهش فشردگی مولکولی می‌شود و پیک هاله بی‌شکل را به‌سمت زوایای کوچک‌تر جابه‌جا می‌کند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Effective Factors on Molecular Packing and Its Effect on Mechanical Properties of Epoxy

نویسندگان [English]

  • Mehran Jahani 1
  • Mehrzad Mortezaei 2
1 master Student
2 Composite Science and Technology Research Center
چکیده [English]

Cured epoxy is a thermosetting polymer with amorphous structure. The amorphous
phase structure reflects the mechanical thermal history of a polymer. Many parameters
in the structure of the amorphous phase affect physical and mechanical properties. One of
the rarely considered parameters is molecular packing. The purpose of this study is to
investigate the factors affecting molecular packing, which leads to changes in mechanical
properties. The measurement of molecular packing by x-ray diffraction is carried out
using the Bragg equation and its approximate estimation is acquired using macroscopic
density. Other equations for calculating chain diffraction and crystal size are introduced
in semi-crystalline systems. Studies have shown that the presence of rigid structures in
the backbone increases the tendency for arrangement. In addition, the branch tends to
increased packing and mechanical properties when it is smaller than the free space between
the chains. Generally in adding additive, the effect increases on molecular packing by
reducing the particle scale. Also, the presence of surface modifiers on particles, especially
in nanoscale particles, results in a matrix arrangement around the particle, an increase in
molecular packing and mechanical properties. The addition of a plasticizer in the system in
the case of fuzzy separation, as the bubble phase becomes larger, there is a reduction in the amount of packing in the chain and displaces the amorphous halo towards smaller angles.

کلیدواژه‌ها [English]

  • X-ray diffraction
  • molecular packing
  • epoxy
  • mechanical properties
  • reinforcement
1. Yang T., Zhang C., Hou X., Cheng J., and Zhang J., The Network Structure and Properties of Multifunctional Epoxy/Anhydride Systems, High Perform. Polym., 28, 854-860, 2016.
2. Park S.J., Jin F.L., and Shin J.S., Physicochemical and Mechanical Interfacial Properties of Trifluorometryl Groups Containing Epoxy Resin Cured with Amine, Mater. Sci. Eng., A, 390, 240-245, 2005.
3. Ochi M., Tsuyuno N., Sakaca K., Nakanishi Y., and Murata Y., Effect of Network Structure on Thermal and Mechanical Properties of Biphenol-Type Epoxy Resins Cured with Phenols, J. Appl. Polym. Sci., 56, 1161-1167, 1995.
4. Vera Graziano R., Hernandez Sanchez F., and Cauich Rodriguez J., Study of Crosslinking Density in Polydimethylsiloxane Networks by DSC, J. Appl. Polym. Sci., 55, 1317-1327, 1995.
5. Vakil U. and Martin G., Crosslinked Epoxies: Network Structure Characterization and Physical–Mechanical Properties, J. Appl. Polym. Sci., 46, 2089-2099, 1992.
6. Vanlandingham M., Eduljee R., and Gillespie J. (Jr), Relationships Between Stoichiometry, Microstructure, and Propertiesfor Amine-Cured Epoxies, J. Appl. Polym. Sci., 71, 699-712, 1999.
7. Chow T.S., Free Volume Distributions in Amorphous Polymers, Macromol. Theory Simul., 4, 397-404, 1995.
8. Murthy N., Correale S., and Minor H., Structure of the Amorphous Phase in Crystallizable Polymers: Poly(ethylene terephthalate), Macromolecules, 24, 1185-1189, 1991.
9. Ronova I. and Pavlova S., The Effect of Conformational Rigidity on Several Physical Properties of Polymers, High Perform. Polym., 10, 309-329, 1998.
10. Hamciuc C., Hamciuc E., Bruma M., and Ronova I.A., Effect of Conformational Rigidity on Physical Properties of Some Poly(imide–amide) Containing Dimethylsilane Units, J. Macromol. Sci., Part A, 42, 61-69, 2005.
11. Ronova I., Structural Aspects in Polymers: Interconnections Between Conformational Parameters of the Polymers with their Physical Properties, Struct. Chem., 21, 541-553, 2010.
12. Yampolskii Y.P., Methods for Investigation of the Free Volume in Polymers, Russ. Chem. Rev., 76, 59-78, 2007.
13. Ronova I.A., Rozhkov E.M., Alentiev A.Y., and Yampolskii Y.P., Occupied and Accessible Volumes in Glassy Polymers and Their Relationship with Gas Permeation Parameters, Macromol. Theory Simul., 12, 425-439, 2003.
14. Ronova I.A., Sokolova E.A., and Bruma M., Influence of Chemical Structure of the Repeating Unit on Physical Properties of Aromatic Polymers Containing Phenylquinoxaline Rings, J. Polym. Sci., Part B: Polym. Phys., 46, 1868-1877, 2008.
15. Bondi A., Van Der Waals Volumes and Radii, J. Phys. Chem., 68, 441-451, 1964.
16. Kozlov G.V. and Novikov V.U., A Cluster Model for the Polymer Amorphous State, Phys. Usp., 44, 681-724, 2001.
17. Choi J.H., Song H.J., Jung J., Yu J.W., You N.H., and Goh M., Effect of Crosslink Density on Thermal Conductivity of Epoxy/ Carbon Nanotube Nanocomposites, J. Appl. Polym. Sci., 134, 44253, 2017.
18. Kumar S., Krishnan S., Samal S.K., Mohanty S., and Nayak S.K., Toughening of Petroleum Based (DGEBA) Epoxy Resins with Various Renewable Resources Based Flexible Chains for High Performance Applications: A Review, Ind. Eng. Chem. Res., 57, 2711-2726, 2018.
19. Hussain R. and Mohammad D., X-ray Diffraction Study of the Changes Induced During the Thermal Degradation of Poly(methyl methacrylate) and Poly(methacryloyl chloride), Turk. J. Chem., 28, 725-730, 2004.
20. Nigam V., Setua D.K., and Mathur G.N., Characterization of Liquid Carboxy Terminated Copolymer of Butadiene Acrylonitrile Modified Epoxy Resin, Polym. Eng. Sci., 39, 1425- 1432, 1999.
21. Liu Y., Chen J., Zhang Y., Gao S., Lu Z., and Xue Q., Highly Thermal Conductive Benzoxazine-Epoxy Interpenetrating Polymer Networks Containing Liquid Crystalline Structures, J. Polym. Sci., Part B: Polym. Phys., 55, 1813-1821, 2017.
22. Kumar S. and Adams W.W., Structural Studies of Epoxy Resins, Acetylene Terminated Resins and Polycarbonate, Polymer, 28, 1497-1504, 1987.
23. Pan G., Du Z., Zhang C., Li C., Yang X., and Li H., Effect of Structure of Bridging Group on Curing and Properties of Bisphenol-A Based Novolac Epoxy Resins, Polym. J., 39, 478-487, 2007.
24. Guo H., Li Y., Zheng J., Gan J., Liang L., Wu K., and Lu M., Reinforcement in the Mechanical Properties of Shape Memory Liquid Crystalline Epoxy Composites, J. Appl. Polym. Sci., 132, 42616, 2015.
25. Welsh W., Bhaumik D., and Mark J., The Flexibility of Various Molecular Swivels Used to Control The Rigidity and Tractability of Aromatic Heterocyclic Polymers, J. Macromol. Sci., Part B: Polym. Phys., 20, 59-84, 1981.
26. Xu K., Chen M., Zhang K., and Hu J., Synthesis and Characterization of Novel Epoxy Resin Bearing Naphthyl and Limonene Moieties, and its Cured Polymer, Polymer, 45, 1133- 1140, 2004.
27. Dai Z., Li Y., Yang S., Zong C., Lu X., and Xu J., Preparation, Curing Kinetics, and Thermal Properties of Bisphenol Fluorene Epoxy Resin, J. Appl. Polym. Sci., 106, 1476-1481, 2007.
28. Sindt O., Perez J., and Gerard J., Molecular Architecture-Mechanical Behaviour Relationships in Epoxy Networks, Polymer, 37, 2989-2997, 1996.
29. Giang T. and Kim J., Effect of Liquid-Crystalline Epoxy Backbone Structure on Thermal Conductivity of Epoxy–Alumina Composites, J. Electron. Mater., 46, 627-636, 2017.
30. Zheng Y., Zou B., and Yuan L., Structure and Properties of Novel Epoxy Resins Containing Naphthalene Units and Aliphatic Chains, Iran. Polym. J., 22, 325-334, 2013.
31. Detwiler A.T. and Lesser A.J., Characterization of Double Network Epoxies with Tunable Compositions, J. Mater. Sci.,47, 3493-3503, 2012.
32. Grishchuk S., Schmitt S., Vorster O., and Karger-Kocsis J., Structure and Properties of Amine-Hardened Epoxy/Benzoxazine Hybrids: Effect of Epoxy Resin Functionality, J. Appl. Polym. Sci., 124, 2824-2837, 2012.
33. Su W.F., Chen K., and Tseng S., Effects of Chemical Structure Changes on Thermal, Mechanical, and Crystalline Properties of Rigid Rod Epoxy Resins, J. Appl. Polym. Sci., 78, 446-451,
2000.
34. Piscitelli F., Lavorgna M., Buonocore G.G., Verdolotti L., Galy J., and Mascia L., Plasticizing and Reinforcing Features of Siloxane Domains in Amine-Cured Epoxy/Silica Hybrids, Macromol. Mater. Eng., 298, 896-909, 2013.
35. Kwon S.C., Adachi T., Araki W., and Yamaji A., Thermo- Viscoelastic Properties of Silica Particulate- Reinforced EpoxyComposites: Considered in Terms of the Particle Packing
Model, Acta Mater., 54, 3369-3374, 2006.
36. Lin K.-F. and Chung U.-L., Phase-Inversion Investigations of Rubber-Modified Epoxies by Electron Microscopy and X-Ray Diffraction, J. Mater. Sci., 29, 1198-1202, 1994.
37. Shiota A. and Ober C.K., Rigid Rod and Liquid Crystalline Thermosets, Prog. Polym. Sci., 22, 975-1000, 1997.
38. Mossety-Leszczak B., Wlodarska M., Galina H., and Bak G., Comparing Liquid Crystalline Properties of Two Epoxy Compounds Based on the Same Azoxy Group, Mol. Cryst. Liq. Cryst., 490, 52-66, 2008.