کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5188981 1381174 2006 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
NMR study of temperature-induced phase separation and polymer-solvent interactions in poly(vinyl methyl ether)/D2O/ethanol solutions
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
NMR study of temperature-induced phase separation and polymer-solvent interactions in poly(vinyl methyl ether)/D2O/ethanol solutions
چکیده انگلیسی
The changes in the dynamic structure during temperature-induced phase transition in D2O/ethanol solutions of poly(vinyl methyl ether) (PVME) were studied using NMR methods. The effect of polymer concentration and ethanol (EtOH) content in D2O/EtOH mixtures on the appearance and extent of the phase separation was determined. Measurements of 1H and 13C spin-spin and spin-lattice relaxations showed the presence of two kinds of EtOH molecules: besides the free EtOH expelled from the PVME mesoglobules there are also EtOH molecules bound in PVME mesoglobules. The existence of two different types of EtOH molecules at temperatures above the phase transition was in solutions with polymer concentration 20 wt% manifested by two well-resolved NMR signals (corresponding to free and bound EtOH) in 13C and 1H NMR spectra. With time the originally bound EtOH is slowly released from globular-like structures. From the point of view of polymer-solvent interactions in the phase-separated PVME solutions both EtOH and water (HDO) molecules show a similar behaviour so indicating that the decisive factor in this behaviour is a polar character of these molecules and hydrogen bonding.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 47, Issue 17, 9 August 2006, Pages 6107-6116
نویسندگان
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