05 مهر 1400
علي يادگاري

علی یادگاری

مرتبه علمی: استادیار
نشانی: دانشکده مهندسی نفت، گاز و پتروشیمی - گروه مهندسی شیمی
تحصیلات: دکترای تخصصی / مهندسی پلیمر
تلفن: 07731222634
دانشکده: دانشکده مهندسی نفت، گاز و پتروشیمی

مشخصات پژوهش

عنوان
Effects of cast extrusion line speed on the crystallinity of LLDPE stretch films
نوع پژوهش مقالات در همایش ها
کلیدواژه‌ها
LLDPE; cast film; Crystallinity; DSC; WAXD
پژوهشگران علی یادگاری (نفر اول) ، هدی بیاضیان (نفر دوم) ، Volker Schöppner (نفر سوم)

چکیده

Influence of line speed on the crystallinity of linear low density polyethylene (LLDPE) stretch films manufactured in a cast extrusion line was examined using differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WAXD). The multilayer LLDPE films were prepared at wide range of line speeds from 200 to 1000 m/min. The DSC results showed that there is an increase in the crystallinity of films at higher line speeds. Furthermore, evaluating melting endotherms indicated that the size of crystals was more uniform as the line speed increased. Crystallinity of films obtained from WAXD analysis also exhibited the similar trend of DSC results, though their values were different. In addition, there was a reduction in crystal size calculated from WAXD data upon increasing the line speed. The observed increase in crystallinity and decrease in crystal size was due to enhanced flow induced crystallization (FIC) as a result of greater shear stresses the polymer melt encountered at higher line speeds.