کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5189187 1381179 2006 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Small-angle X-ray scattering and linear melt rheologyof poly(tert-butyl acrylate-g-styrene) graft copolymers
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Small-angle X-ray scattering and linear melt rheologyof poly(tert-butyl acrylate-g-styrene) graft copolymers
چکیده انگلیسی
The morphology and rheological properties have been studied for poly(tert-butyl acrylate-g-styrene), PtBA-g-S, graft copolymers through the analysis of different samples that varied in the number of grafted repeat units. Small-angle X-ray scattering (SAXS) measurements confirmed phase separation in these samples, and showed the presence of disordered microdomains on those copolymers with a grafting number higher than 7. SAXS results have also shown a significant improvement of microdomain segregation with temperature manifesting considerable changes in both intensity, position and full-width half-maximum of the peak q*, which is attributed to the graft-like nature of these systems. The frequency dependence of the dynamic moduli revealed three relaxation mechanisms. The low-frequency (long time) relaxation was identified with the movement of the whole molecule, the relaxation at intermediate time is related to movement of the grafts, and the high-frequency relaxation is like that found in the transition zone of main chain of poly(tert-butyl acrylate), PtBA. The rheological measurements indicated that the introduction of a small amount of polystyrene, PS, grafts in the PtBA backbone is sufficient to modify mechanical behaviour at low frequencies. Comparison of the rheological properties of the graft copolymers with higher PS content showed that the observed changes in the viscoelastic behaviour under shear seems to be related to both the microphase separated microstructure and the number of grafts present in the copolymers.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 47, Issue 5, 22 February 2006, Pages 1487-1495
نویسندگان
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