Ionic transient species in irradiated poly(vinyl chloride) film |
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| Institution: | 1. Department of Fundamental Chemistry, Federal University of Pernambuco, Recife 50740-560, Brazil;2. Department of Chemistry, Gdansk University of Technology, Gdansk 80233, Poland;1. Integrated Science Education and Research Centre, Siksha-Bhavana, Visva-Bharati, Santiniketan 731 235, India;2. Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India;3. Department of Chemistry, Siksha-Bhavana, Visva-Bharati, Santiniketan 731 235, India;1. Normal College, Shenyang University, Shenyang 110044, China;2. School of Equipment Engineering, Shenyang Ligong University, Shenyang 110159, China;1. Materials Science Program, VU Station B 351826, Nashville, TN 37235-1826, United States;2. Chemical and Biomolecular Engineering, VU Station B 351604, Nashville, TN 37235-1604, United States;3. Mechanical Engineering, VU Station B 351592, Nashville, TN 37235-1592, United States |
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| Abstract: | The studies of transient species in irradiated poly(vinyl chloride) (PVC) film have been carried out with the main aim of investigating the charge trapping in a pure system. In PVC, pulse radiolysis gives electron-positive hole pairs. The electron can generate a matrix anion due to the presence of chlorine atom in the PVC macromolecules followed by Cl? detachment. The positive hole may be stabilized as a short-lived matrix cation characterized by visible absorption band with wide maximum in the 350–650 nm range. The positive holes can be scavenged by additives like pyrene, Py and respective radical-ions of Py can be detected. The rate of Py radical cations decay at ～450 nm was found to be temperature dependent. Two linear parts of the Arrhenius plot were observed which intersected in the 200–240 K range, which is close to the mechanical loss peak connected with the β relaxation in PVC matrix. The activation energies calculated for two parts of Arrhenius plot were equal to 0.40 kJ mol?1 for T < 200 K and 52.6 kJ mol?1 for T > 240 K. The novel mechanism of the ionic and radical reactions in PVC is proposed and discussed. |
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