کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5187321 1381126 2017 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
A near-infrared study of thermally induced structural changes in polyethylene crystal
ترجمه فارسی عنوان
مطالعه ای نزدیک به مادون قرمز از تغییرات ساختاری ایجاد شده در دما در بلورهای پلی اتیلن
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
چکیده انگلیسی

Thermally induced structural changes of polyethylene (PE) have been studied by means of near-infrared (NIR) spectroscopy in the course of heating up to the melting temperature. NIR bands characteristic of the regular orthorhombic phase, the conformationally disordered hexagonal phase, and the amorphous phase have been successfully identified. It has been found that for the unoriented PE sample, the disordering process of orthorhombic lattice starts above room temperature and that it mostly occurs above 100 °C for the uniaxially oriented PE sample. In the latter case, the enhancement of crystallinity has clearly been detected just below Tm due to the reorganization of crystalline lattice. For the geometrically constrained ultradrawn PE sample, the phase transition from orthorhombic to hexagonal phase has been detected immediately below the melting point. The NIR bands characteristic of the hexagonal phase have been confirmed definitely. Usefulness of NIR spectroscopy has been demonstrated successfully in such a study of thermally induced phase transition behavior of PE samples with appreciable thickness, for which mid-IR spectroscopy is difficult to apply because of the intensity saturation of various key bands.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 47, Issue 6, 8 March 2006, Pages 2010-2017
نویسندگان
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