Home Development of β and α isotactic polypropylene polymorphs in injection molded structural foams
Article
Licensed
Unlicensed Requires Authentication

Development of β and α isotactic polypropylene polymorphs in injection molded structural foams

  • Strashimir Djoumaliisky EMAIL logo , Maria Cerrada , Tatyana Dobreva and Peter Zipper
Published/Copyright: February 5, 2010
Become an author with De Gruyter Brill
Author Information
Chemical Papers
From the journal Chemical Papers Volume 64 Issue 2

Abstract

Structural foam moldings, composed of three co-axial cylinders differing in diameter (10 mm, 20 mm, and 30 mm) and length, were produced from isotactic polypropylene (PP) and 0.5 mass % 1,1′-azobisformamide on an in-line injection molding machine in a mould cavity pre-pressurized with nitrogen by the classical low-pressure process combined with egression of foamed melt from the core. Injection-molding conditions were as follows: melt temperature, 220°C, mold temperature, 20°C, cooling time, 5 min, gas-counter pressure, 0.5 MPa. The sprue gate was at the end of the smallest cylinder and its diameter was varied from 4 mm to 7 mm. To investigate the development of β-PP modification in terms of phenomena due to the phase change in the mould cavity (expansion), appropriate specimens (cross-sections) were cut from the middle of each cylinder in parallel and perpendicular orientation to the flow direction and were investigated by WAXS, DSC, and POM. As revealed by WAXS, β-PP is present in all cylinders, always concentrated in certain regions of the cross-section — mainly in the surface layers of the smallest cylinder (D1) and in the foamed core of the other two cylinders (D2 and D3). Its concentration was found to change with the sprue dimensions. High β-PP concentration is associated with a preferred orientation in the skin of the smallest cylinder and with better expansion conditions in larger cylinders. Presence of the β-phase in the surface layers and in the core of the moldings was proved by DSC and POM.

Keywords: polypropylene; foams; beta; phase; WAXS; DSC

[1] Arranz-Andrés, J., Peña, B., Benavente, R., Pérez, E., & Cerrada, M. L. (2007). Influence of isotacticity and molecular weight on the properties of metallocenic isotactic polypropylene. European Polymer Journal, 43, 2357–2370. DOI: 10.1016/j.eurpolymj.2007.03.034. http://dx.doi.org/10.1016/j.eurpolymj.2007.03.03410.1016/j.eurpolymj.2007.03.034Search in Google Scholar

[2] Chu, F., Yamaoka, T., Ide, H., & Kimura, Y. (1994). Microvoid formation process during the plastic deformation of β-form polypropylene. Polymer, 35, 3442–3448. DOI: 10.1016/0032-3861(94)90906-7. http://dx.doi.org/10.1016/0032-3861(94)90906-710.1016/0032-3861(94)90906-7Search in Google Scholar

[3] Dimeska, A., & Phillips, P. J. (2006). High pressure crystallization of random propylene-ethylene copolymers: α-γ phase diagram. Polymer, 47, 5445–5456. DOI: 10.1016/j.polymer.2005.11.097. http://dx.doi.org/10.1016/j.polymer.2005.11.09710.1016/j.polymer.2005.11.097Search in Google Scholar

[4] Djoumaliisky, S., & Touleshkov, N. (1996). A modification of the low pressure foam moulding process. Journal of Material Science and Technology, 4, 32–41. Search in Google Scholar

[5] Fillon, B., Thierry, A., Wittmann, J. C., & Lotz, B. (1993). Self-nucleation and recrystallization of polymers. Isotactic polypropylene, β phase: β-α conversion and β-α growth transitions. Journal of Polymer Science Part B: Polymer Physics, 31, 1407–1424. DOI: 10.1002/polb.1993.090311015. http://dx.doi.org/10.1002/polb.1993.09031101510.1002/polb.1993.090311015Search in Google Scholar

[6] Fleischmann, E., Zipper, P., Jánosi, A., Geymayer, W., Koppelmann, J., & Schurz, J. (1989). Investigations of the layered structure of injection-molded polypropylene discs and of its behavior in tensile tests. Dedicated to Prof. H. Janeschitz-Kriegl on the occasion of his 65th birthday. Polymer Engineering and Science, 29, 835–843. DOI: 10.1002/pen.760291212. http://dx.doi.org/10.1002/pen.76029121210.1002/pen.760291212Search in Google Scholar

[7] Fujiyama, M. (1995). Higher order structure of injection-molded polypropylene. In J. Karger-Kocsis, J. (ed.), Polypropylene: Structure, blends and composites (pp. 167–204). London, UK: Chapmann & Hall. Search in Google Scholar

[8] Fujiyama, M., Wakino, T., & Kawasaki, Y. (1988). Structure of skin layer in injection-molded polypropylene. Journal of Applied Polymer Science, 35, 29–49. DOI: 10.1002/app.1988.070350104. http://dx.doi.org/10.1002/app.1988.07035010410.1002/app.1988.070350104Search in Google Scholar

[9] Kantz, M. R., Newman, H. D., & Stigale, F. H. (1972). The skin-core morphology and structure-property relationships in injection-molded polypropylene. Journal of Applied Polymer Science, 16, 1249–1260. DOI: 10.1002/app.1972.070160516. http://dx.doi.org/10.1002/app.1972.07016051610.1002/app.1972.070160516Search in Google Scholar

[10] Kotzev, G., Djoumaliisky, S., Krasteva, M., Iliev, M., Pérez, E., & Cerrada, M. L. (2007). Effect of sample configuration on the morphology of foamed LDPE/PP blends injection molded by a gas counterpressure process. Macromolecular Materials and Engineering, 292, 769–779. DOI: 10.1002/mame.200700030. http://dx.doi.org/10.1002/mame.20070003010.1002/mame.200700030Search in Google Scholar

[11] Krache, R., Benavente, R., López-Majada, J. M., Pereña, J. M., Cerrada, M. L., & Pérez, E. (2007). Competition between α, β, and γ polymorphs in a β-nucleated metallocenic isotactic polypropylene. Macromolecules, 40, 6871–6878. DOI: 10.1021/ma0710636. http://dx.doi.org/10.1021/ma071063610.1021/ma0710636Search in Google Scholar

[12] Lotz, B., Kopp, S., & Dorset, D. (1994) Sur une structure cristalline originale de polymères en conformation hélicoidale 31 ou 32. Comptes Rendus de l’Academie des Sciences (Paris), Serie IIb, 319, 187–192. Search in Google Scholar

[13] Meille, S. V., Ferro, D. R., Brueckner, S., Lovinger, A. J., & Padden, F. J. (1994). Structure of β-isotactic polypropylene: a long-standing structural puzzle. Macromolecules, 27, 2615–2622. DOI: 10.1021/ma00087a034. http://dx.doi.org/10.1021/ma00087a03410.1021/ma00087a034Search in Google Scholar

[14] Menyhárd, A., Varga, J., & Molnár, G. (2006). Comparison of different β-nucleators for isotactic polypropylene, characterisation by DSC and temperature-modulated DSC measurements. Journal of Thermal Analysis and Calorimetry, 83, 625–630. DOI: 10.1007/s10973-005-7498-6. http://dx.doi.org/10.1007/s10973-005-7498-610.1007/s10973-005-7498-6Search in Google Scholar

[15] Mezghani, K., & Phillips, P. J. (1998). The γ-phase of high molecular weight isotactic polypropylene: III. The equilibrium melting point and the phase diagram. Polymer, 39, 3735–3744. DOI: 10.1016/S0032-3861(97)10121-5. http://dx.doi.org/10.1016/S0032-3861(97)10121-510.1016/S0032-3861(97)10121-5Search in Google Scholar

[16] Moitzi, J., & Skalicky, P. (1993). Shear-induced crystallization of isotactic polypropylene melts: isothermal WAXS experiments with synchrotron radiation. Polymer, 34, 3168–3172. DOI: 10.1016/0032-3861(93)90385-N. http://dx.doi.org/10.1016/0032-3861(93)90385-N10.1016/0032-3861(93)90385-NSearch in Google Scholar

[17] Obadal, M., Čermák, R., Baran, N., Stoklasa, K., & Šimoník, J. (2004). Impact strength of β-nucleated polypropylene. International Polymer Processing, 1, 35–39. 10.3139/217.1802Search in Google Scholar

[18] Pérez, E., Zucchi, D., Sacchi, M. C., Forlini, F., & Bello, A. (1999). Obtaining the γ phase in isotactic polypropylene: effect of catalyst system and crystallization conditions. Polymer, 40, 675–681. DOI: 10.1016/S0032-3861(98)00291-2. http://dx.doi.org/10.1016/S0032-3861(98)00291-210.1016/S0032-3861(98)00291-2Search in Google Scholar

[19] Rybnikář, F. (1991). Transition of β to α phase in isotactic polypropylene. Journal of Macromolecular Science, Part B Physics, 30, 201–223. DOI: 10.1080/00222349108215449. http://dx.doi.org/10.1080/0022234910821544910.1080/00222349108215449Search in Google Scholar

[20] Ščudla, J., Raab M., Eichhorn, K.-J., & Strachota, A. (2003). Formation and transformation of hierarchical structure of β-nucleated polypropylene characterized by X-ray diffraction, differential scanning calorimetry and scanning electron microscopy. Polymer, 44, 4655–4664. DOI: 10.1016/S0032-3861(03)00287-8. http://dx.doi.org/10.1016/S0032-3861(03)00287-810.1016/S0032-3861(03)00287-8Search in Google Scholar

[21] Shi, G.-y., Zhang, X.-d., Cao, Y.-h., & Hong, J. (1993). Melting behavior and crystalline order of β-crystalline phase poly(propylene). Die Makromolekulare Chemie, 194, 269–277. DOI: 10.1002/macp.1993.021940123. http://dx.doi.org/10.1002/macp.1993.02194012310.1002/macp.1993.021940123Search in Google Scholar

[22] Turner Jones, A., Aizlewood, J. M., & Beckett, D. R. (1964). Crystalline forms of isotactic polypropylene. Macromolecular Chemistry and Physics, 75, 134–158. DOI: 10.1002/macp.-1964.020750113. http://dx.doi.org/10.1002/macp.1964.020750113Search in Google Scholar

[23] Varga, J. (2002). β-modification of isotactic polypropylene: preparation, structure, processing, properties, and application. Journal of Macromolecular Science, Part B Physics, 41, 1121–1171. DOI: 10.1081/MB-120013089. http://dx.doi.org/10.1081/MB-12001308910.1081/MB-120013089Search in Google Scholar

[24] Varga, J. (1992). Supermolecular structure of isotactic polypropylene. Journal of Materials Science, 27, 2557–2579. DOI: 10.1007/BF00540671. http://dx.doi.org/10.1007/BF0054067110.1007/BF00540671Search in Google Scholar

[25] Varga, J., & Menyhárd, A. (2007). Effect of solubility and nucleating duality of N,N′-dicyclohexyl-2,6-naphthalenedicarboxamide on the supermolecular structure of isotactic polypropylene. Macromolecules, 40, 2422–2431. DOI: 10.1021/ma062815j. http://dx.doi.org/10.1021/ma062815j10.1021/ma062815jSearch in Google Scholar

[26] Varga, J., Tóth-Schulek, F., & Ille, A. (1991). Effect of fusion conditions of β-polypropylene on the new crystallization. Colloid & Polymer Science. 269, 655–664. DOI: 10.1007/BF00657402. http://dx.doi.org/10.1007/BF0065740210.1007/BF00657402Search in Google Scholar

[27] Yamaguchi, M., Fukui, T., Okamoto, K., Sasaki, S., Uchiyama, Y., & Ueoka, C. (2009), Anomalous molecular orientation of isotactic polypropylene sheet containing N,N′-dicyclohexyl-2,6-naphthalenedicarboxamide. Polymer, 50, 1497–1504. DOI: 10.1016/j.polymer.2009.01.033. http://dx.doi.org/10.1016/j.polymer.2009.01.03310.1016/j.polymer.2009.01.033Search in Google Scholar

[28] Zhang, X., & Shi, G. (1994). Effect of converting the crystalline form from α to β on the mechanical properties of ethylene/propylene random and block copolymers. Polymer, 35, 5067–5072. DOI: 10.1016/0032-3861(94)90666-1. http://dx.doi.org/10.1016/0032-3861(94)90666-110.1016/0032-3861(94)90666-1Search in Google Scholar

[29] Zipper, P., Abuja, P. M., Jánosi, A., Wrentschur, E., Geymayer, W., Ingolic, E., & Friesenbichler, W. (1995). Comparative wide-angle X-ray and microscopical studies on the layered structure in injection molded polypropylene disks. International Polymer Processing, 4, 341–350. 10.3139/217.950341Search in Google Scholar

[30] Zipper, P., & Djoumaliisky, S. (2002a). Site-resolved wide-angle X-ray studies on structural PP foams injection-molded by the low-pressure process. Journal of Macromolecular Science, Part B Physics, 41, 725–743. DOI: 10.1081/MB-120013061. http://dx.doi.org/10.1081/MB-12001306110.1081/MB-120013061Search in Google Scholar

[31] Zipper, P., & Djoumaliisky, S. (2002b). Site-resolved X-ray scattering studies, II the morphology in injection-molded PP foams. Macromolecular Symposia, 181, 421–426. DOI: 10.1002/1521-3900(200205)181:1<421::AID-MASY421>3.0.CO;2-6. http://dx.doi.org/10.1002/1521-3900(200205)181:1<421::AID-MASY421>3.0.CO;2-610.1002/1521-3900(200205)181:1<421::AID-MASY421>3.0.CO;2-6Search in Google Scholar

[32] Zipper, P., Jánosi, A., Geymayer, W., Ingolic, E., & Fleischmann, E. (1996). Comparative X-ray scattering, microscopical, and mechanical studies on rectangular plates injection molded from different types of isotactic polypropylene. Polymer Engineering and Science, 36, 467–482. DOI: 10.1002/pen.10433. http://dx.doi.org/10.1002/pen.1043310.1002/pen.10433Search in Google Scholar

Published Online: 2010-2-5
Published in Print: 2010-4-1

© 2009 Institute of Chemistry, Slovak Academy of Sciences

Articles in the same Issue

  1. Co-digestion of agricultural and industrial wastes
  2. Comparison of anoxic granulation in USB reactors with various inocula
  3. A study of selected phytoestrogens retention by reverse osmosis and nanofiltration membranes - the role of fouling and scaling
  4. Displacement washing of kraft pulp cooked from a blend of hardwoods
  5. Solid suspension and gas dispersion in gas-solid-liquid agitated systems
  6. Implementation of marginal quantities in management of cogeneration units operating in liberal market environment
  7. Kinetic study of wood chips decomposition by TGA
  8. LES and URANS modelling of turbulent liquid-liquid flow in a static mixer: Turbulent kinetic energy and turbulence dissipation rate
  9. Steady state and dynamic simulation of a hybrid reactive separation process
  10. Prediction of liquid-liquid flow in an SMX static mixer using large eddy simulations
  11. Simulation of a hybrid fermentation-separation process for production of butyric acid
  12. Simulation of aerobic landfill in laboratory scale lysimeters — effect of aeration rate
  13. Application of anoxic fixed film and aerobic CSTR bioreactor in treatment of nanofiltration concentrate of real textile wastewater
  14. Pretreatment of landfill leachate by chemical oxidation processes
  15. Development of β and α isotactic polypropylene polymorphs in injection molded structural foams
  16. Effect of time on the metal-support (Fe-MgO) interaction in CVD synthesis of single-walled carbon nanotubes
  17. Unique role of water content in enzymatic synthesis of ethyl lactate using ionic liquid as solvent
  18. Autothermal biodrying of municipal solid waste with high moisture content
  19. Kinetics of nitric oxide oxidation
https://doi.org/10.2478/s11696-009-0107-6
Keywords for this article
polypropylene; foams; beta; phase; WAXS; DSC

Articles in the same Issue

  1. Co-digestion of agricultural and industrial wastes
  2. Comparison of anoxic granulation in USB reactors with various inocula
  3. A study of selected phytoestrogens retention by reverse osmosis and nanofiltration membranes - the role of fouling and scaling
  4. Displacement washing of kraft pulp cooked from a blend of hardwoods
  5. Solid suspension and gas dispersion in gas-solid-liquid agitated systems
  6. Implementation of marginal quantities in management of cogeneration units operating in liberal market environment
  7. Kinetic study of wood chips decomposition by TGA
  8. LES and URANS modelling of turbulent liquid-liquid flow in a static mixer: Turbulent kinetic energy and turbulence dissipation rate
  9. Steady state and dynamic simulation of a hybrid reactive separation process
  10. Prediction of liquid-liquid flow in an SMX static mixer using large eddy simulations
  11. Simulation of a hybrid fermentation-separation process for production of butyric acid
  12. Simulation of aerobic landfill in laboratory scale lysimeters — effect of aeration rate
  13. Application of anoxic fixed film and aerobic CSTR bioreactor in treatment of nanofiltration concentrate of real textile wastewater
  14. Pretreatment of landfill leachate by chemical oxidation processes
  15. Development of β and α isotactic polypropylene polymorphs in injection molded structural foams
  16. Effect of time on the metal-support (Fe-MgO) interaction in CVD synthesis of single-walled carbon nanotubes
  17. Unique role of water content in enzymatic synthesis of ethyl lactate using ionic liquid as solvent
  18. Autothermal biodrying of municipal solid waste with high moisture content
  19. Kinetics of nitric oxide oxidation
Sign up now to receive a 20% welcome discount
Institutional Access
How does access work?
Have an idea on how to improve our website?
Please write us.
© 2025 De Gruyter Brill
Downloaded on 27.11.2025 from https://www.degruyterbrill.com/document/doi/10.2478/s11696-009-0107-6/html
Scroll to top button