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 Influence of precursor film microstructure on properties of HDPE microporous membranes prepared by stretching
نوع پژوهش مقالات در نشریات
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مجله JOURNAL OF APPLIED POLYMER SCIENCE
شناسه DOI
پژوهشگران علی یادگاری (نفر اول) ، جلیل مرشدیان (نفر دوم) ، حسین علی خنکدار (نفر سوم) ، Udo Wagenknecht (نفر چهارم) ، Gert Heinrich (نفر پنجم)

چکیده

Oriented HDPE films having a stacked lamellar morphology were prepared to develop microporous membranes through cast film extrusion followed by stretching. Applying higher draw ratios (DR) and annealing the cast films improved crystal alignments remarkably. It was shown the improvement in c-axis orientation upon annealing was more significant for the films prepared with lower DR. Furthermore, applying Raman spectroscopy, the amorphous mass fraction of the films was obtained. Subsequently, considering a three-phase structure (i.e., crystal, amorphous and interphase), the interphase content of the films was also determined. A distinct DR dependence of the interphase content was noticed. It was observed that in addition to crystal perfection upon annealing, the amorphous phase fraction was also decreased due to possibly increase in free volume, promoting lamellar separation and cavitation during the subsequent stretching step. SEM images of the membranes surfaces as well as their normalized water vapor transmission rate (WVTR) values indicated a more uniform pore formation and increased permeability with DR. Furthermore, it was found that lower interphase content in the films with higher DR favors lamellar separation. However, permeability in the stretched precursor films with DR higher than a certain level (DR593) was not improved significantly. Moreover, crystallinity and crystal orientation of produced membranes were investigated.