کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5185775 1381087 2007 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Temperature dependence of polymorphism in electrospun nanofibres of PA6 and PA6/clay nanocomposite
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Temperature dependence of polymorphism in electrospun nanofibres of PA6 and PA6/clay nanocomposite
چکیده انگلیسی

Polymorphism found in nanofibres of polyamide 6 (PA6) and PA6/clay nanocomposite (PA6-NC), prepared by an electrospinning process, was studied by transmission electron microscopy (TEM) and variable-temperature wide angle X-ray scattering (WAXS), and compared with the polymorphic changes occurring in the pre-electrospun bulk materials. TEM results, concerning morphology and dispersion of the nanoclays, reveal that the produced electrospun nanofibres have an average diameter of 50 nm, and nanoclays are much more uniformly dispersed in the electrospun PA6-NC fibres than in the pristine PA6-NC. According to WAXS measurements, both types of electrospun nanofibres predominantly consist of γ-form crystals of PA6. Upon heating, from room temperature to the melting point, a number of successive transitions are observed for both systems, namely, crystalline γ to α′, α′ to α and α to the “amorphous” δ-form due to breakage of hydrogen bonds. On subsequent cooling, it has been observed, for the first time, that the development of crystalline forms for both systems is quite different from each other. The molten electrospun pure PA6 fibres first crystallize in the high temperature α′-form, and then they show the room temperature α-form. For these nanofibres, during a temperature cycle of heating and cooling, the initial γ-form crystals completely turn into the α-form crystals as in bulk PA6. In contrast, for the electrospun nanofibres of the PA6-NC, the γ-form crystals are preserved after completing a thermal cycle down to room temperature. The present findings on the evolution of polymorphism in the electrospun nanofibres of both systems provide useful information regarding their use as reinforcing elements in polymer composites.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 48, Issue 16, 27 July 2007, Pages 4814-4823
نویسندگان
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