The effect of high-energy electron beam on drawn and undrawn high density polyethylene fibers

Document Type: Original research

Authors

1 Faculty of Processing, Iran Polymer and Petrochemical Institute, P.O. Box 14975/112, Tehran, Iran

2 Islamic Azad University of Tehran

3 Tehran University

Abstract

HDPE monofilaments were obtained using different extruders and drawn by post-extruder equipments. After solidification, drawn and undrawn monofilaments (draw ratio 7:1) were irradiated with 10 MeV electron beams in air at room temperature at 25, 50, 75, 100 and 125 kGy dose ranges to induce a network structure. HDPE crosslinking was studied on the basis of gel content measurements. The fibers were examined by differential scanning calorimetry (DSC) and measurements of mechanical properties.
It was noted that gel fraction increased with irradiation dose up to 75 kGy and showed a significant increase with draw ratio, but at higher doses remained without considerable change. Melting temperature of drawn fiber increased with raising irradiation dose but decreased in undrawn sample. Also a bimodal endotherm peak was observed for drawn polyethylene irradiated in air.
The changes in melting temperature and appearance of bimodal endotherm were related to the radiation chemistry of polyethylene in the presence of oxygen and interlamellar interactions. Heat of fusion and degree of crystallinity slightly increased for undrawn and drawn samples but, heat of crystallization was reduced by increasing irradiation dose due to increase the degree of crosslinking. Results of mechanical properties reveal that no significant changes seen in Young’s modulus by increasing irradiation dose. As a result of oxidative degradation happened by presence the oxygen molecules during the irradiation process, tensile properties of irradiated fibers decreased but elongation at yield for undrawn and elongation at break for drawn fibers boosted by increasing irradiation dose up to 125 kGy.

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  1. Ladizesky NH (1986) The drawing behavior of linear polyethylene: Effect of electron irradiation on drawing and subsequent mechanical behavior of drawn products. J Macromol Sci: Part B 25: 185-213
  2. Woods DW, Busfield WK, Ward IM (1988) Improved mechanical-behavior in ultra high modulus polyethylene by controlled crosslinking. Polym Commun 29: 250-252
  3. Galiatatos V, Eichinger BE (1988), Simulations on radiation-cured polyethylene. J Polym Sci: Part B 26: 595-602
  4. Khonakdar HA (2006) Effect of electron-irradiation on cross-link density and crystalline structure of low- and high-density polyethylene. Rad Phys Chem 75: 78–86
  5. Meola C (2003) Experimental evaluation of properties of cross-linked polyethylene. Mater Manuf Process 18: 135–144
  6. Meola C (2004) Chemical and irradiation cross-linking of polyethylene. Technological performance over costs. Polym Plast Technol Eng 43: 631–648
  7. Wünsche P (1984) Generation of free radicals by increasing the temperature after γ- irradiation of polyethylene. J Macromol Sci B 23: 65 – 84
  8. Dole M (1981) History of the Irradiation Cross- Linking of Polyethylene. J Macromol Sci A 15: 1403-1409
  9. Hikmet R, Keller A (1987) Crystallinity dependent free radical formation and decay in irradiated polyethylene in the presence of oxygen. Int J Rad Appl Instrum C 29: 15-19
  10. Perez CJ, Vallés EM, Failla MD (2010) The effect of post-irradiation annealing on the crosslinking of high-density polyethylene induced by gamma-radiation. Rad Phys Chem 49: 710-715
  11. Zaydouri A, Grivet M (2009) The effect of electron irradiation on high-density polyethylene: Positron annihilation lifetime spectroscopy, differential scanning calorimetry and X-ray scattering studies. Rad Phys Chem 78: 750-755
  12. Dawes K (2007) The effects of electron beam and g-irradiation on polymeric materials In: Physical properties of polymers handbook, Mark JE (ed), 2nd ed., Springer Science
  13.  Adler G (1963) Cross-linking of polymer by radiation. Science 141: 321-329
  14. Gheysari D (2001) The effect of high-energy electron beam on mechanical and thermal properties of LDPE and HDPE. Eur Polym J 37: 295-302
  15. Perkins WG (1978) Effect of gamma radiation and annealing on ultra-oriented polyethylene. Polym Eng Sci 18: 527-532
  16. Hu J (1999) Degradation of interpenetrating polymer networks based on PE and polymethacrylates by electron beam irradiation. Polymer 40: 5279–5284
  17. Pearson RW (1957) Mechanism of the radiation crosslinking of polyethylene. J Polym Sci 25: 189-200
  18. Zoepfl FJ (1984) Differential scanning calorimetry studies of irradiated polyethylene: I. Melting temperatures and fusion endotherms. J Polym Sci: Polym Chem 22: 2017–2032
  19. Okada Y, Awemiya A (1961) Effect of atmosphere on radiation-induced crosslinking of polyethylene. J Polym Sci 50: 22-24
  20. Okada Y (1963) Effect of atmosphere on radiation-induced crosslinking of polyethylene: III. Effect of various gases and effect of electric field. J Appl Polym Sci 7: 1153-1163
  21. Carpentieri I (2011) Post-irradiation oxidation of different polyethylene. Polym Degrad Stabil 96: 624-629
  22. Hama Y (2011) Long-term oxidative degradation in polyethylene irradiated with ion beams. Rad Phys Chem 62: 133-139
  23. Seguchi T (1983) Radiation induced oxidative degradation of polymers: III. Effect of radiation on mechanical properties. Rad Phys Chem 21: 495-501
  24. Black RM, Charlesby A (1959) The oxidation of irradiated polyethylene I radio-oxidation. Int J Appl Rad Isotope 7: 127-133
  25. Narkis M (1987) Structure and tensile behavior of irradiation- and peroxide- crosslinked polyethylenes. J Macromol Sci B 26: 37- 58
  26. Seguchi T (1983) Radiation induced oxidative degradation of polymers II. Effects of radiation on swelling and gel fraction of polymers. Rad Phys Chem 19: 495-501
  27. Basfar AA, Ali KMI (2004) Effect of various additives on tensile properties of polyethylene films irradiated in air, water, N2, and vacuum. Polym Plast Technol Eng 43: 389–405
  28. Klein PG (1987) The effect of electron irradiation on the structure and mechanical properties of highly drawn polyethylene fibers. J Polym Sci: Polym Phys 25: 1359-137
  29. QU B, Ranby B (1995) Radiation crosslinking of polyethylene with electron beam at different temperatures. Polym Eng Sci 35: 1161-1166
  30. Tillet G (2011) Chemical reactions of polymer crosslinking and post-crosslinking at room and medium temperature. Prog Polym Sci 36: 191-217
  31. Gheysari D, Behjat A (2001) Radiation crosslinking of LDPE and HDPE with 5 and 10 MeV electron beams. Eur Polym J 37: 2011-2016
  32. Akay G (1990) The effect of molecular orientation on gamma-radiation induced crosslinking in high density polyethylene. Rad Phys Chem 36: 337-343
  33. Akay G (1980) The effect of orientation on the radiation induced degradation of polymers. Eur Polym J 16: 597-600
  34. Kawai T (1965) The effect of crystallization conditions on radiation- induced crosslink formation in polyethylene. Philosoph Mag 12: 657-671
  35. Zoepfl FJ (1984) Differential scanning calorimetry studies of irradiated polyethylene: II. The effect of oxygen. J Polym Sci: Polym Chem 22: 2033-2045
  36. Southern JH Porter RS (1972) Melting behavior of polyethylene crystallized in a pressure capillary viscometer. J Polym Sci A 10: 1135-1143
  37. Geetha R (1988) Radiation-induced degradation of polyethylene effect of processing and density on the chemical changes and mechanical properties. Polym Degrad Stabil 23: 91-98