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
Stretching Poly (lactic acid) extruded films at different drawing speeds and temperatures
نوع پژوهش مقالات در همایش ها
کلیدواژه‌ها
PLA; cast film; tensile properties; surface morphology
پژوهشگران علی یادگاری (نفر اول) ، هدی بیاضیان (نفر دوم) ، Volker Schöppner (نفر سوم)

چکیده

Poly (lactic acid), PLA, is a commercially available biodegradable and bio-based polymer which is accepted as a potential to replace conventional polymers in packaging applications. Oriented PLA films are obtained through stretching at temperatures above its glass transition. The present study evaluates the effects of temperature and drawing speed during stretching on the tensile behavior and surface morphology of PLA films. Increasing the drawing speed (from 1 to 30 mm/s) enhances the strain hardening behavior. Conversely, there is a noticeable reduction in strain hardening as stretching temperature increases from 70 °C to 80 °C. However, stretching at 90 °C eliminates, thoroughly, the strain hardening behavior. The surface morphology of PLA films observed by scanning electron microscopy (SEM) reveals no crystalline structures on the film surface of PLA films stretched at lower temperature (70 °C). The SEM image of PLA film stretched at higher temperature (90 °C) indicates formation of crystalline lamellae which is attributed to cold crystallization during stretching.