کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5191936 1381243 2005 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Polymer class specificity of the glass temperature
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Polymer class specificity of the glass temperature
چکیده انگلیسی
It is shown that assuming linearity of the polymer class specific correlation between the glass transition temperature and the ratio mass to effective number of 'flexible' bonds of monomeric (repeat) unit, μ/ρ, it is possible to evaluate by least square fit the 'flexibility' factor, ρ, characterizing the share of those simple bonds within the repeat unit responsible for conformational rearrangements of the polymer. The evaluated effective number of simple bonds accounts for the influence of polymer class specific interactions and steric hindrances on the 'free rotation' of the simple bonds comprised in the repeat unit. It is shown that the well-known increase of the glass transition temperature of polymers bearing longer n-alkylic side chains may be the result of preferred 'crankshaft' like motions of neighboring methylenes, hindering the 'free rotation' of the simple bonds between the methylenes involved in the 'crankshaft'. It is also possible to quantify steric hindrances of bulky substituents.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 46, Issue 7, 10 March 2005, Pages 2230-2237
نویسندگان
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