کد مقاله کد نشریه سال انتشار مقاله انگلیسی ترجمه فارسی نسخه تمام متن
5197788 1381439 1990 16 صفحه PDF سفارش دهید دانلود کنید
عنوان انگلیسی مقاله ISI
Motional heterogeneity and the nature of the interphase in block copolymers: a2H nuclear magnetic resonance study
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Motional heterogeneity and the nature of the interphase in block copolymers: a2H nuclear magnetic resonance study
چکیده انگلیسی
Poly(styrene-b-isoprene) block copolymers with 50 wt% styrene andMn = 10 000 and 20 000 g mol−1 labelled by deuterated styrene (isoprene) segments at the block boundary have been studied by2H nuclear magnetic resonance spectroscopy andCp measurements. In both the styrene- and isoprene-deuterated block copolymer spectra, two kinds of thermal transitions are observed, the main glass transition and an interphase transition. By simulation of the spectra and byT1 measurements, the upper and lower limits for the correlation times of the motion of styrene and isoprene segments on both sides of the interface have been determined. The equivalent dynamical interphase width of isoprene units with restricted mobility in the interphase having mean correlation times of the order of 10−6 s at 300 K was evaluated to be 7A˚and 5A˚forMn = 10 000 andMn = 20 000 of the block copolymers, respectively. The analysis of the motional heterogeneity presents evidence of an asymmetric segmental density and motional profile characterized by a styrene-rich interphase, mixing of some isoprene segments into the glassy phase and negligible mixing of styrene segments into the elastomer phase.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 31, Issue 10, October 1990, Pages 1838-1853
نویسندگان
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