کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
675389 1459597 2009 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Glass transition in thermosetting clay-nanocomposite polyurethanes
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
Glass transition in thermosetting clay-nanocomposite polyurethanes
چکیده انگلیسی

In this work nanocomposite in a polyurethane (PU) matrix, using an organically modified montmorillonite (OMM), were studied. An amount of organoclay ranging from 2% up to 6% by volume was added to the polyol component of the resin before mixing with isocyanate.The basal distance of OMM before and after mixing with the polyol and after curing was characterized by X-ray diffraction. The glass transition temperature (Tg) of PU nanocomposites, measured using differential scanning calorimeter, increases with increasing the volume fraction of OMM. On the other hand, the heat capacity increment, ΔCp, decreases from that the unfilled PU to that of the sample with 5.7 vol.% of OMM. Therefore the rigid amorphous fraction of the PU nanocomposites increases with increasing volume fraction of OMM. Finally, a three-phase model similar to that applied to study semi-crystalline polymers, was used to analyze the intercalation of the PU chains between OMM lamellae. The definition of molecular cooperativity was discussed for these systems and the characteristic length of the cooperative region was determined, using Donth equation.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Thermochimica Acta - Volume 485, Issues 1–2, 10 March 2009, Pages 43–48
نویسندگان
, ,