Skip to main content
SpringerLink
Log in

Effect of crystallization temperature and propylene sequence length on the crystalline structure of propylene-ethylene random copolymers

  • Articles
  • Polymer Physics
  • Published:
Chinese Science Bulletin

Abstract

Crystallization behavior and resultant crystalline structure of a series of temperature-rising elution-fractionated specimen of a Ziegler-Natta catalyst-synthesized propylene-ethylene random copolymer were studied by DSC, WAXD and AFM. The experimental results indicate that both crystallization temperature and propylene sequence length exhibit great influence on the crystallization behavior and crystalline structure of the copolymer. It was found that the ethylene co-monomers acting as point defects inserted into the polypropylene chains play an important role in the formation of γ-iPP. As the co-monomer content increases, the crystallizable sequence length of iPP decreases, which produces an appropriate condition for its γ crystallization. At the same time, the existence of chain defects leads to a lower crystallinity of the copolymer and imperfection of the resultant crystals. For each individual sample with certain propylene sequence length or ethylene content, the increment of γ-iPP crystal content with increasing crystallization temperature demonstrates that higher crystallization temperature is in favor of the γ-iPP crystallization. Pure γ-iPP crystals have been got in samples with propylene sequence length lower than 21 under suitable crystallization conditions.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. Natta G, Corradini P, Ganis P. Prediction of the conformation of the chain in the crystalline state of tactic polymers. J Polym Sci, 1962, 58: 1191–1199

    Article  Google Scholar 

  2. Turner-Jones A. Cocrystallization in copolymers of alpha olefins II-butene-copolymers and polybutene type II/I crystal phase transition. Polymer, 1966, 7: 23–59

    Article  Google Scholar 

  3. Turner-Jones A. Development of the γ-crystal form in random ccopolymers of propylene and their analysis by DSC and X-ray methods. Polymer, 1971, 12: 487–507

    Article  CAS  Google Scholar 

  4. Bruckner S, Meille S V. Non-parallel chains in crystalline γ-isotactic polypropylene. Nature, 1989, 340: 455–457

    Article  CAS  Google Scholar 

  5. Bruckner S, Meille S V, Petraccone V, et al. Polymorphism in isotactic polypropylene. Prog Polym Sci, 1991, 16: 361–404

    Article  CAS  Google Scholar 

  6. Ferro D R, Bruckner S, Meille S V, et al. Energy calculations for isotactic polypropylene: A comparison between models of the α and γ crystalline structures. Macromolecules, 1992, 25: 5231–5235

    Article  CAS  Google Scholar 

  7. Ferro D R, Bruckner S, Meille S V. Energy calculations for isotactic polypropylene: A contribution to clarify the beta crystalline structure. Macromolecules, 1998, 31: 6926–6934

    Article  CAS  Google Scholar 

  8. Anderson Campbell R, Phillips P J, Lin J S. The gamma phase of high-molecular-weight polypropylene: 1. Morphological aspects. Polymer, 1993, 34: 4809–4816

    Article  Google Scholar 

  9. Lotz B, Wittmann J C, Lovinger A J. Structure and morphology of poly(propylenes): A molecular analysis. Polymer, 1996, 37: 4979–4992

    Article  CAS  Google Scholar 

  10. Mezghani K, Phillips P J. The γ-phase of high molecular weight isotactic polypropylene. II: The morphology of the γ-form crystallized at 200 Mpa. Polymer, 1997, 38: 5725–5733

    Article  CAS  Google Scholar 

  11. Mezghani K, Phillips P J. The γ-phase of high molecular weight isotactic polypropylene: III. The equilibrium melting point and the phase diagram. Polymer, 1998, 39: 3735–3744

    Article  CAS  Google Scholar 

  12. Nogales A, Hsiao B S, Somani R H, et al. Shear-induced crystallization of isotactic polypropylene with different molecular weight distributions: in situ small-and wide-angle X-ray scattering studies. Polymer, 2001, 42: 5247–5256

    Article  CAS  Google Scholar 

  13. Foresta T, Piccarolo S, Goldbeck-Wood G. Competition between α and γ phases in isotactic polypropylene: Effects of ethylene content and nucleating agents at different cooling rates. Polymer, 2001, 42: 1167–1176

    Article  CAS  Google Scholar 

  14. Rosa C D, Auriemma F, Circelli T, et al. Crystallization of the α and γ forms of isotactic polypropylene as a tool to test the degree of segregation of defects in the polymer chains. Macromolecules, 2002, 35: 3622–3629

    Article  Google Scholar 

  15. Auriemma F, Rosa C D. Crystallization of metallocene-made isotactic polypropylene: Disordered modifications intermediate between the α and γ forms. Macromolecules, 2002, 35: 9057–9068

    Article  CAS  Google Scholar 

  16. Auriemma F, Rosa C D. Stretching isotactic polypropylene: From “cross-β” to crosshatches, from α form to α form. Macromolecules, 2006, 39: 7635–7647

    Article  CAS  Google Scholar 

  17. Alamo R G, Ghosal A, Chatterjee J, et al. Linear growth rates of random propylene ethylene copolymers. The changeover from γ dominated growth to mixed (α+γ) polymorphic growth. Polymer, 2005, 46: 8774–8789

    CAS  Google Scholar 

  18. Alamo R G, Man-Ho Kim, Galante M J, et al. Structural and kinetic factors governing the formation of the γ polymorph of isotactic polypropylene. Macromolecules, 1999, 32: 4050–4064

    Article  CAS  Google Scholar 

  19. Hosier IL, Alamo R G, Esteso P, et al. Formation of the α and γ polymorphs in random metallocene-propylene copolymers. Effect of concentration and type of comonomer. Macromolecules, 2003, 36: 5623–5636

    Article  CAS  Google Scholar 

  20. Hosier IL, Alamo R G, Lin J S. Lamellar morphology of random metallocene propylene copolymers studied by atomic force microscopy. Polymer, 2004, 45: 3441–3455

    Article  CAS  Google Scholar 

  21. Alamo R G, Ghosal A, Chatterjee J, et al. Linear growth rates of random propylene ethylene copolymers. The changeover from γ dominated growth to mixed (α+γ) polymorphic growth. Polymer, 2005, 46: 8774–8789

    CAS  Google Scholar 

  22. Feng Y, Jin X, Hay J N. Evaluation of multiple melting peaks of propylene-ethylene copolymers. Polymer J, 1998, 30: 215–221

    Article  CAS  Google Scholar 

  23. Harding G W, Van Reenen A J. Fractionation and characterisation of propylene-ethylene random copolymers: Effect of the comonomer on crystallisation of poly(propylene) in the γ-phase. Macromol Chem Phys, 2006, 207: 1680–1690

    Article  CAS  Google Scholar 

  24. Hong S M, Seo Y. Crystallization of a polypropylene terpolymer made by a ziegler-natta catalyst: Formation of γ-phase. J Phys Chem B, 2007, 111: 3571–3575

    Article  PubMed  CAS  Google Scholar 

  25. Mezghani K, Phillips P J. γ-Phase in propylene copolymers at atmospheric pressure. Polymer, 1995, 36: 2407–2411

    Article  CAS  Google Scholar 

  26. Lotz B, Graff S, Wittmann J C. Crystal morphology of the gamma (triclinic) phase of isotactic polypropylene and its relation to the alpha phase. J Polym Sci Part B Polym Phys, 1986, 24: 2017–2032

    Article  CAS  Google Scholar 

  27. Laihonen S, Gedde U W, Werner P E, et al. Crystallization kinetics and morphology of poly(propylene-stat-ethylene) fractions. Polymer, 1997, 38: 361–369

    Article  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Beijing National Laboratory for Molecular Sciences, and State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100080, China

    QingQiang Gou, Li HuiHui & ShouKe Yan

  2. Department of Polymer Science, School of Chemistry, Peking University, Beijing, 100871, China

    ZhenQiang Yu & ErQiang Chen

  3. Beijing Research Institute of Chemical Industry, SINOPEC, Beijing, 100013, China

    YuDong Zhang

Authors
  1. QingQiang Gou
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Li HuiHui
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. ZhenQiang Yu
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. ErQiang Chen
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. YuDong Zhang
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. ShouKe Yan
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to ShouKe Yan.

Additional information

Ph. D. candidate of Graduate University of Chinese Academy of Sciences, Beijing 100039, China

Supported by the Outstanding Youth Fund of the National Natural Science Foundation of China (Grant No 20425414), National Natural Science Foundations of China (Grant Nos. 50521302, 20423003, 20574079, and 20604031), and State “973” Programs from the Ministry of Science and Technology of China (Grant No. 2003CB615602)

About this article

Cite this article

Gou, Q., HuiHui, L., Yu, Z. et al. Effect of crystallization temperature and propylene sequence length on the crystalline structure of propylene-ethylene random copolymers. Chin. Sci. Bull. 53, 1804–1812 (2008). https://doi.org/10.1007/s11434-008-0252-2

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11434-008-0252-2

Keywords

Search

Navigation