کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
28675 | 44085 | 2006 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Ionic transient species in irradiated poly(vinyl chloride) film
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
بیو مهندسی (مهندسی زیستی)
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چکیده انگلیسی
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 Clâ 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 â¼450 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 molâ1 for T < 200 K and 52.6 kJ molâ1 for T > 240 K. The novel mechanism of the ionic and radical reactions in PVC is proposed and discussed.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 177, Issues 2â3, 25 January 2006, Pages 185-190
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 177, Issues 2â3, 25 January 2006, Pages 185-190
نویسندگان
J. Mayer, M. Szadkowska-Nicze,