Temperature‐dependent fluorescence from pyrenyl‐modified polyethylene films. A comparison of attachment methods and morphology changes by irradiation with eV‐range photons and bombardment with MeV‐range positive ions

摘要: 1-Pyrenyl groups were attached covalently to three polyethylene (Py–PE) films with different crystallinities by irradiating (eV-range photons–UV-photons) or bombarding (MeV-range ions–protons and alpha particles) pyrene-doped PE (Py/PE). Onset temperatures of relaxation processes (Tx) the Py–PE approximated from (1) Arrhenius-type plots normalized integrated intensities (2) temperature dependence full-width half-maximum (FWHM) position 0–0 fluorescence band. DSC thermograms native irradiated bombarded also compared independently assess morphological changes. The onset Tx in lower crystallinity more difficult locate when prepared bombardment high doses than low photons ions irradiation. ease locating higher was independent dose, suggesting little change mobility vicinity pyrenyl probes. Fluorescence particles indicated presence both singly- doubly-attached groups. singly-attached less sensitive doubly Tx. luminescence reporters Tγ segmental motions 9-anthryl same polymers. We discuss possible reasons why values activation energies for processes, as calculated Arrhenius plots, much smaller those based on dynamic mechanical methods. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Phys 42: 2957–2970,