Radiation crosslinking of LDPE and HDPE with 5 and 10 MeV electron beams

The radiation crosslinking of low density polyethylene (LDPE) and high density polyethylene (HDPE) irradiated with 5 and 10 MeV electron beams at dose range of 50 up to 250 kGy is investigated. The crosslinking of PE is studied on the basis of gel content measurement and Fourier transform infra-red (FTIR) spectroscopy. The yields of gel contents increase with increasing dose value in both LDPE and HDPE samples but this increase is slightly lower for 10 MeV electron compared with 5 MeV. The FTIR spectra show that the concentration of trans-vinylene double bonds in crosslinked LDPE and HDPE induced by 10 MeV electron beam, increases with increasing irradiation dose while the concentration of the vinyle double bonds in HDPE decreases. Dose-depth distribution for 10 MeV electron beams in polyethylene shows that 10 MeV electrons penetrate deep into polyethylene. It is observed that about 90% of the surface dose is left at 40 mm depth. (C) 2001 Elsevier Science Ltd. All rights reserved.