کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5184155 1381040 2011 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Structural characterization of poly(ε-caprolactone)-grafted cellulose acetate and butyrate by solid-state 13C NMR, dynamic mechanical, and dielectric relaxation analyses
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Structural characterization of poly(ε-caprolactone)-grafted cellulose acetate and butyrate by solid-state 13C NMR, dynamic mechanical, and dielectric relaxation analyses
چکیده انگلیسی

Investigations were made into the molecular dynamics and intercomponent mixing state in solid films of two series of cellulosic graft copolymers, cellulose acetate-g-poly(ε-caprolactone) (CA-g-PCL) and cellulose butyrate-g-PCL (CB-g-PCL), both series being prepared over a wide range of compositions with CAs or CBs of acyl DS ≈ 2.1, 2.5, and 2.95. It was shown by T1ρH measurements in solid-state 13C NMR spectroscopy that all the copolymer samples, except ones using CA of DS = 2.98, formed an amorphous monophase in which the trunk and graft components were mixed homogeneously at least in a scale of a few nanometers. However, those copolymer samples gave, more or less, a response of dynamic heterogeneity, when examined under mechanical oscillation. Through dielectric relaxation measurements, a clear comparison was made between the CA-g-PCL and CB-g-PCL series, regarding the cooperativeness in segmental motions of the trunk and graft chains, directly associated with the extent of the dynamic heterogeneity. The cooperativeness was generally higher in the CB-based copolymer series, probably due to working of the butyryl substituent as an internal compatibilizer.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 52, Issue 25, 28 November 2011, Pages 5912-5921
نویسندگان
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