کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
231904 1427463 2007 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Solid–fluid phase behaviour of linear polyethylene solutions in propane, ethane and ethylene at high pressures
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
Solid–fluid phase behaviour of linear polyethylene solutions in propane, ethane and ethylene at high pressures
چکیده انگلیسی

The solid–fluid phase transitions for a series of linear polyethylene fractions (Mw: 800, 7000, 23 625, 52 000, 59 300 g/mol) in propane, ethane and ethylene were measured in the temperature range from 360 to 423 K and at pressures up to 2000 bar. Conditions of precipitation of the solid polyethylene from supercritical solutions seem to have minor influence on dissolution of the solid polymer in supercritical solvents. In general, an increase of pressure results in a shift of the solid–fluid phase transition to higher temperatures, i.e. solubility of polyethylene decreases. The solid–fluid phase boundaries for systems composed of low-molecular weight polyethylene and propane show temperature minima. The effect is not observed in the high-molecular weight polyethylene + propane systems and systems with ethane or ethylene as solvents. It was observed that the temperature of the solid–fluid phase transition measured at a constant pressure and a constant composition is not a monotonic function of molecular weight of the polymer. The order of the dissolution temperatures depends on pressure.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: The Journal of Supercritical Fluids - Volume 43, Issue 2, December 2007, Pages 357–366
نویسندگان
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