کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5184468 1381048 2011 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Electron diffraction and molecular modelling investigation of the crystal structure of poly (para-phenylene terephthalamide) form II
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Electron diffraction and molecular modelling investigation of the crystal structure of poly (para-phenylene terephthalamide) form II
چکیده انگلیسی

Microsingle crystals of poly(para-phenylene terephthalamide), abbreviated PPTA, were obtained by water-vapor induced precipitation of PPTA rigid-flexible copolymers in sulfuric acid solution. Electron diffraction was performed and yielded hk0 patterns. The crystal structure of a model compound, N, N′ para (4-methoxycarbonyl) phenylene dibenzamide, abbreviated 3ARB-COOMe, is also reported. Its structure is compatible with that of the polymer, in which aromatic rings are all coplanar and form a 30° angle with amide groups. A reinvestigation of form II, based on electron diffraction data and molecular modeling simulations, is reported. The proposed space group is P112, and corresponds to a parallel chain arrangement, with terephthaloyl groups facing one another, and carbonyl groups pointing in opposite directions along the b-axis in adjacent hydrogen-bonded sheets. Chain conformation is the same as in form I, as previously established. The 3ARB-COOMe conformation is suggested as a possible polymorph or as defects in the crystal phase.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 52, Issue 18, 18 August 2011, Pages 4083-4092
نویسندگان
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