کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1484817 1510531 2007 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Molecular dynamics of poly (oxybutylene)s confined in pores of Vycor glass
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
Molecular dynamics of poly (oxybutylene)s confined in pores of Vycor glass
چکیده انگلیسی
We have investigated the relaxation dynamics of poly (oxybutylene), POB, chains of various lengths, with different end groups (OH and CH3) in bulk and in confinement using dielectric relaxation spectroscopy. It is known that POB chains exhibit, apart from the segmental (main) relaxation process, the dielectric normal mode process which reflects the global chain motions. The comparative study of OH- and methyl-ended POB chains in bulk reveals the marked effect of association of hydroxyl end groups and indicates that the decrease in the density of the methylated specimens results in the acceleration of both relaxation processes, main and normal mode relaxations. For the confined POB chains the data indicate that the segmental relaxation process becomes faster (the effect being more pronounced for the methylated POB chains). A decrease in Tg of about 8 K for the methyl- and 2 K for OH-ended POB chains is estimated. Regarding the average relaxation rates of the normal mode process our data indicate that global chain mobility is not affected by the confinement.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Non-Crystalline Solids - Volume 353, Issues 47–51, 1 December 2007, Pages 4318-4323
نویسندگان
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