The relationship among changes in microstructure, active sites behavior and properties in the propylene polymerization with a 4th generation Ziegler-Natta catalyst

Document Type: Original research

Authors

Department of Polymerization Engineering, Iran Polymer and Petrochemical Institute, P.O. Box: 14965/115, Tehran, Iran

Abstract

Three polypropylene samples (1-3) were synthesized with a 4th generation Ziegler-Natta catalyst in the presence of cyclohexyldimethoxymethylsilane (donor c), dicyclopenthyldimethoxysilane (donor d) and diisopropyldimethoxysilane (donor p), respectively, as external electron donors. The physical properties of the synthesized polypropylenes were determined. For samples 1 to 3, Successive self-nucleation and annealing (SSA) and Fourier transform infrared spectroscopy (FT-IR) analyses indicated that the relative content of the fraction with high isotacticity and regularity in conformational structure decreased in contrast with the fraction of low isotacticity and low uniformity in stereo-defect distribution from sample 1 to 3. The results demonstrated that the longer the isotactic sequence length and the less uniform the stereo-defect distribution, the greater the conformational order. Deconvolution of the molecular weight distribution curves indicated that the stability of the active centers increased from samples 1 to 3, but the participation of stereo-specefic active centers in the polymerization decreased. DMA tests showed that samples 3 and 1 had the highest damping ability and storage modulus, respectively.

Keywords

Main Subjects


  1. Genis AV (2015) Analysis of the global and Russian markets of polypropylene and of its main consumption area. Russ J Electrochem 87: 2137- 2150
  2. Shen X, Fu Z, Hu J, Wang Q, Fan Z (2013) Mechanism of propylene polymerization with Mg-Cl2 supported Ziegler-Natta catalysts based on counting of active centers: The role of external electron donor. J Phys Chem C 117: 15174-15182
  3. Piryanshu B, Sukhdeep K, (2011) Synthesis of polypropylene with varied microstructure and molecular weights characteristics using supported titanium supported catalyst system. J Polym Res 18: 235-239
  4. Zohouri G, Kasaeian A, Angagi M, Jamjah R, Mousavian A, Emami M, Ahmadjo S (2005) Polymerization of propylene using MgCl2 (ethoxide type)/TiCl4/diether heterogenous Ziegler-Natta catalyst. Polym Int 54: 882-885
  5. Zohouri G, Azimfar F, Jamjah R, Ahmadjo S, (2002) Polymerization of propylene using the high activity Ziegler_Natta catalyst system SiO2/MgCl2 (Ethoxide type) /TiCl4/Di-n-buthyl phthalate/Triethylaluminium/Dimethoxy Methyl Cyclohexyl Silane. J Appl Polym Sci 89: 1177- 1181
  6. Maddipati SV, Delgass WN, Caruthers JM, (2011) Determination of the catalytic sites for Ziegler Natta homo-polymerization from GPC data. Macromol Theory Simul 20: 31-45
  7. Kim SY, Hiraoka Y, Taniike T, Terano M, (2009) External donor induced direct contact effects on Mg(OC2H5)2 – Based Z-N catalysts for propylene polymerization. Macromol Symp 285: 115-120
  8. Matsouka H, Liu B, Nakatani H, Nishiyama I, Terano M (2002) Active sites deterioration of MgCl2 supported catalyst induced by the electron donor extraction by alkylaluminum. Polym Int 51: 781-784
  9. Potapov A.G, Bukatov G.D, Zakharov V.A (2010) DRIFTS study of the interaction of the Internal donor in TiCl4 di-n-butyl phthalate/MgCl2 catalysts with AlEt3 cocatalyst. J. Mol. Catal A: Chem 316: 95-99.
  10. Piryanshu B, Sukhdeep K (2011) Synthesis of polypropylene with varied microstructure and molecular weights characteristics using supported titanium supported catalyst system. J Polym Res 18: 235-239
  11. Hakim S, Nekoomanesh M, Shahrokhinia A (2015) The effect of mixed and individual silane external donors on the stereo-defect distribution, active sites and properties of polypropylene synthesized with fourth generation Ziegler-Natta catalyst. Polym Sci-A 25: 573-580
  12. Vestberg T, Denifl P, Parkinson M (2010) Effects of external donors and hydrogen concentration on oligomer formation and chain end distribution in propylene polymerization with Z-N catalysts. J Polym Sci Pol Chem 48: 351-358
  13. Chadwick J, Morini G, Balbontin G (2001) Effects of Internal and External donors on regio and stereoselectivity of active species in MgCl2 supported catalysts for propene polymerization. Macromol Chem Phys 202: 1995-2002
  14. Lou J, Tu S, Fan Z, (2010) Polypropylene chain structure regulation by alkoxy silane and ether type external donors in TiCl4/DIBP/MgCl2-AlEt3 Ziegler-Natta catalyst. Iran Polym J 19: 927-936
  15. Kang J, Feng Y, Tong W, Huilin L, Ya C, Ming X (2012) Polymerization control and fast characterization of the stereo-defect distribution of heterogeneous Ziegler-Natta isotactic polypropylene. Eur Polym J 48: 425-434
  16. Xu J, Feng L, Yang S, Yang Y, Kong X (1998) Temperature rising elution fractionation of polypropylene produced by heterogeneous Ziegler-Natta catalysts. Eur Polym J 34: 431-434
  17. Monrabal B, Sancho-Tello J, Mayo N, Romero L, (2007) Crystallization elution fractionation. A new separation process for polyolefin resins. Macromol Symp 257: 71-79
  18. Zhao J, Peng Z, Zhang J, Li J (2011) In situ FT-IR spectroscopy study on the conformational changes of quenched isotactic polypropylene during stepwise heating. Polym Bull 67: 1649- 1659
  19. Li B, Li L, Zhao L, Yuan W (2008) In-situ FT-IR spectroscopic study on the conformational changes of isotactic polypropylene in the presence of supercritical CO2. Eur Polym J 44: 2619-2624
  20. Zhu X, Yan D, Yao H, Zhu P (2000) In situ FT-IR spectroscopic study of the regularity bands and partial-order melts of isotactic poly(propylene). Macromol Rapid Commun 21: 354-357
  21. Kang J, Yang F, Wu T, Li H, Liu D, Cao Y, Xiang M (2012) Investigation of the stereo-defect distribution and conformational behavior of isotactic polypropylene polymerized with different Ziegler-Natta catalysts. J Appl Polym Sci 125: 3076-3083
  22. Zhu X, Yan D, Fang Y (2001) In situ FT-IR spectroscopic study of the conformational change of isotactic polypropylene during the crystallization process. J Phys Chem B 105: 12461-12463
  23. Brandrup J (1989) Polymer Handbook. Wiely, 90- 95
  24. Fillon B, Wittmann J.C, Lotz B, Thierry A (1993) Self nucleation and enhanced nucleation of polymers. Definition of a convenient calorimetric efficiency scale and evaluation of nucleating additives in isotactic polypropylene. J Polym Sci Pol Phys 31: 1383-1393
  25. Wlochowitcz A, Eder M (1984) Distribution of lamella thicknesses in isothermally crystallized polypropylene by differential scaning calorimetry. Polymer 25: 1268-1270
  26. Garoff T, Virkkunene V, Jaaskelainen P, Vestberg T (2004) qualitative model for polymerization of propylene with a Z-N catalyst. Eur Polym J 39: 1679-1685
  27. Paolini Y, Ronca G, Feijoo J, Silva E, Ramirez J, Muller A (2001) Application of SSA calorimetric technique to characterize an XLPE insulator aged under multiple stresses. Macromol Chem Phys 202: 1539-1547
  28. Fan Z, Feng L, Yang S (1996) Distribution of active centers on TiCl4/MgCl2 catalyst for olefin polymerization. J Polym Sci Pol Chem 34: 3329- 3335
  29. Kissin YV, (1995) Molecular weight distribution of linear polymers: Detailed analysis from GPC data. J Polym Sci Pol Chem 33: 227-237
  30. Kioka M, Makio H, Mizuno A, Kashiwa N (1994) Tacticity distribution of polypropylene prepared by MgCl2- supported titanium catalyst. Polymer 35: 580-583