کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5191853 1381242 2005 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Fluorescence response from anthracene labeled polystyrene to study its thermal transitions
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Fluorescence response from anthracene labeled polystyrene to study its thermal transitions
چکیده انگلیسی

In this work, thermal transitions of polystyrene, PS, were studied as a function of molecular weight (Mw) and thermal history using the fluorescence response of anthracene chemically bonded to the polymer chain ends. For each PS sample the fluorescence spectra of the anthracene were collected as a function of temperature in cycles of heating and cooling. Two photophysical parameters were selected in order to study thermal transitions of the PS samples: (i) the first moment of the fluorescence band, 〈ν〉; and (ii) the integrated fluorescence intensity, I. In every case, a sharp change in the photophysical parameter was observed at a certain temperature that was assigned to the α relaxation temperature and which was clearly different depending on the PS molecular weight and the thermal history. In fact, the relaxation temperature increased with Mw during a heating scan, decreased with Mw during a cooling scan and was clearly lower in the cooling scans. These results were interpreted in terms of a reorientation of the anthryl groups to the surface of the polymer.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 46, Issue 12, 26 May 2005, Pages 4023-4031
نویسندگان
, , , ,