کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1396374 | 984173 | 2009 | 6 صفحه PDF | دانلود رایگان |
In this work, the characteristics of the β and γ mechanical relaxations, i.e., temperature and relative intensity, of a series of metallocene iPP samples (MPP) are analysed. The hypothesis that the temperature and the intensity of the glass transition (β relaxation) and local sub-Tg motions (γ relaxation) are related mainly to chain parameters and morphology has been corroborated. On the one hand, it has been found a critical average isotactic length (n1) around 30 propylene units, under which the β and γ dynamics are promoted with respect to the α relaxation. On the other hand, it is apparent that the features which determine the degree of constraint within the inter-lamellar region, i.e., the fraction of low-Tm crystals, drive the relative intensities of the α, β and γ relaxation processes.
Journal: European Polymer Journal - Volume 45, Issue 4, April 2009, Pages 1322–1327