Radiation grafting of vinyl monomers onto poly(tetrafluoroethylene) powder produced by gamma irradiation and properties of grafted poly(tetrafluoroethylene) filled low density polyethylene

Akinay E., Tincer T.

JOURNAL OF APPLIED POLYMER SCIENCE, cilt.79, sa.5, ss.816-826, 2001 (SCI İndekslerine Giren Dergi) identifier


Scrap poly(tetrafluoroethylene) (PTFE) was gamma irradiated under an ambient atmosphere in order to produce extensive chain scission and oxidative degradation. After irradiation the PTFE was ground into a fine powder (2 degrees -PTFE) and graft;ed with styrene (St), vinyl acetate (VAc), and 4-vinylpyridine (4-VP) by using the direct irradiation technique. The grafted PTFE were then blended with low density polyethylene (LDPE). The study covered the characterization of irradiated PTFE and grafted 2 degrees -PTFE powder with various methods. Mechanical grinding was found to reduce trapped radicals formed during the irradiation process faster than the annealing process. Grafting on 2 degrees -PTFE was followed by gravimetric analysis, TGA, and the change in the particle size of the samples. Although we reached almost 20% grafting by weight in the St and 4-VP monomers, VAc grafting was found to be maximum at around 8% by weight at the maximum absorbed dose. The addition of VAc grafted 2 degrees -PTFE into LDPE produced better final mechanical properties with a fine dispersion. However, as may be expected, the incorporation of the other two 2 degrees -PTFEs into LDPE showed low film quality and poor mechanical properties. (C) 2000 John Wiley & Sons, Inc.