Electron beam irradiation method to change polypropylene application: Rheology and thermomechanical properties

Document Type : Original research


Department of Chemical and Polymer Engineering, Faculty of Engineering, Yazd University, 891581–8411, Iran.


Irradiation of polymers is one of the most effective and economical methods for modifying their properties and for changing their applications. In this study, an extrusion grade polypropylene (PP) was treated by electron beam irradiation to produce a PP suitable for injection molding. Irradiation was carried out at different doses (0-80 kGy) under atmosphere air and at ambient temperature. Melt flow index (MFI) measurements showed PP samples irradiated in the range of 10 to 40 kGy are suitable to use in injection molding. Electron beam irradiation decreased the viscosity and the shear thinning rheological behavior of PP. The differential scanning calorimetry (DSC) analysis revealed that electron beam irradiation increased the crystallinity percentage and temperature of PP, but decreased the melting temperature. Among all treated samples, the PP20, irradiated at the dose of 20 kGy, showed the highest impact resistance. It had higher Young’s modulus and tensile strength, but lower elongation-at-break in comparison with untreated PP.


Main Subjects

  1. Yoshiga A, Otaguro H, Parra DF, Lima LFCP, Lugao AB (2009) Controlled degradation and crosslinking of polypropylene induced by gamma radiation and acetylene. Polymer bull 63: 397- 409
  2. Shin SH, Petrov S (2004) Crosslinking and degradation of polypropylene by electron beam irradiation in the presence of trifunctional monomers. Radiat Phys Chem 69: 239-244
  3. Singh A (1999), Irradiation of polyethylene: Some aspects of crosslinking and oxidative deg-radation. Radiat Phys Chem 56: 375-380
  4. Tabb D, Sevcik J, Koenig J (1975) Fourier transform infrared study of the effects of irradiation on polyethylene. J Polym Sci Pol Phys 13: 815-824
  5. Truica-Marasescu F, Jedrzejowski P, Wertheimer MR (2004) Hydrophobic recovery of vacuum ultraviolet irradiated polyolefin surfaces. Plasma Proc Polym 1: 153-163
  6. Chapiro A (1988), Chemical modifications in irradiated polymers. Nucl Ins Methods Phys Res B 32: 111-114
  7. Lagendijk R, Hogt AH, Buijtenhuijs A, Gotsis AD (2001) Peroxydicarbonate modification of polypropylene and extensional flow properties. Polymer 42: 10035-10043
  8. Gotsis A, Zeevenhoven B, Tsenoglou C (2004) Effect of long branches on the rheology of polypropylene. J Rheol 48: 895-914
  9. Abiona AA, Osinkolu AG (2010) Gamma-irradiation induced property modification of polypropylene. Int J Phys Sci 5: 960-967
  10. Sugimoto M, Tanaka T, Masubuchi Y, Takimoto JI, Koyama K (1999) Effect of chain structure on the melt rheology of modified polypropylene. J Appl Polym Sci 73: 1493-1500
  11. Clough R (2001) High-energy radiation and polymers: A review of commercial processes and emerging applications. Nucl Ins Methods Phys Res B 185: 8-33
  12. Lugão AB, Hutzler B, Ojeda T, Tokumoto S, Siemens R, Makuuchi K, Villavicencio ALCH (2000) Reaction mechanism and rheological properties of polypropylene irradiated under various atmospheres. Radiat Phys Chem 57: 389-392
  13. Auhl D, Stange J, Münstedt H (2004) Long-chain branched polypropylenes by electron beam irradiation and their rheological properties. Macromolecules 37: 9465-9472
  14. Krause B, Voigt D, Häuβler L, Auhl D, Münstedt H (2006) Characterization of electron beam irradiated polypropylene: influence of irradiation temperature on molecular and rheological properties. J Appl Polym Sci 100: 2770-2780
  15. Auhl D, Stadler FJ, Münstedt H (2012) Rheological properties of electron beam-irradiated poly-propylenes with different molar masses. Rheol acta 51: 979-989
  16. Van Gisbergen J, Meijer H, Lemstra P (1989) Structured polymer blends: 2. Processing of poly-propylene/EDPM blends: Controlled rheology and morphology fixation via electron beam irradiation. Polymer 30: 2153-2157
  17. Van Gisbergen J, Hoeben W, Meijer H (1991) Melt rheology of electron-beam-irradiated blends, of polypropylene and ethylene-propylene-diene monomer (EPDM) rubber. Polym Eng Sci 31: 1539-1544
  18. Naskar K, Gohs U, Heinrich G (2009) PP-EPDM thermoplastic vulcanisates (TPVs) by electron induced reactive processing. eXPRESS Polym Lett 3: 677-683
  19. Rooj S, Thakur V, Gohs U, Wagenknecht U, Bhowmick AK, Heinrich G (2011) In situ reactive compatibilization of polypropylene/epoxidized natural rubber blends by electron induced reactive processing: Novel in-line mixing technology. Polym Adv Technol 22: 2257-2263
  20. Thakur V, Gohs U, Wagenknecht U, Heinrich G (2012) Electron-induced reactive processing of thermoplastic vulcanizate based on polypropylene and ethylene propylene diene terpolymer rubber. Polym J 44: 439-448
  21. Mondal M, Gohs U, Wagenknecht U, Heinrich G (2013) Polypropylene/natural rubber thermoplastic vulcanizates by eco-friendly and sustainable electron induced reactive processing. Radiat Phys Chem 88: 74–81
  22. Razavi Aghjeh M, Khonakdar HA, Jafari SH, Zschech C, Gohs U, Heinrich G (2016) Rheological, morphological and mechanical investigations on ethylene octene copolymer toughened polypropylene prepared by continuous electron induced reactive processing. RSC Adv 6: 24651-24660
  23. Naskar K, Gohs U, Heinrich G (2016) Influence of molecular structure of blend components on the performance of thermoplastic vulcanisates prepared by electron induced reactive processing. Polymer 91: 203-210
  24. Arroyo M, Zitzumbo R, Avalos F (2000) Composites based on PP/EPDM blends and aramid short fibers. Morphology/behavior relationship. Polymer 41: 6351-6359
  25. Auhl D, Stadler FJ, Münstedt H (2012) Comparison of molecular structure and rheological properties of electron-beam-and gamma-irradiated polypropylene. Macromolecules 45: 2057-2065
  26. Reyes J, Albano C, Davidson E, Poleo R, González J, Ichazo M, Chipara M (2001) Effects of gamma irradiation on polypropylene, polypropylene+ high density polyethylene and polypropylene+ high density polyethylene+ wood flour. Mater Res Innov 4: 294-300
  27. Yan D, Wang WJ, Zhu S (1999) Effect of long chain branching on rheological properties of metallocene polyethylene. Polymer 40: 1737- 1744
  28. Lohse DJ, Milner ST, Fetters LJ, Xenidou M (2002) Well-defined, model long chain branched polyethylene. 2. Melt rheological behavior. Macromolecules 35: 3066-3075
  29. Kagiya T, Nishimoto S (1985) Importance of the amorphous fraction of polypropylene in the resistance to radiation-induced oxidative degradation, Polym Degrad Stabil 12: 261-275