کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7061331 | 1459018 | 2015 | 18 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Rheological behavior and structure development in thermoplastic polyurethanes under uniaxial extensional flow
ترجمه فارسی عنوان
رفتار رئولوژیکی و ساختار ساختاری در پلی اورتان های گرمانرم تحت جریان یکپارچه
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
جریان سیال و فرایندهای انتقال
چکیده انگلیسی
In this work, the rheological and structural changes induced by uniaxial extensional flows are studied for two aromatic TPUs: an elastomeric (soft) material composed both of hard and soft segments and an amorphous glass (hard) one composed almost exclusively by hard segments. The uniaxial extensional viscosity was measured on a Sentmanat fixture (SER) at single temperature of 175 °C, showing that at high strain rates both materials initially strain-soften before eventually strain-hardening at higher Hencky strains. This effect is smoother and occurs at lower strain rates for the soft TPU. Optical microscopy, atomic force microscopy and X-ray scattering show this behavior to be related with structural changes induced by the flow. Strain-softening is attributed to the orientation of hard domains in the flow direction. In the soft TPU strain-hardening is caused by the stretching of entangled soft segments but in the hard one it appears to be associated with microcracks and with the development of a hitherto unreported hierarchical structure in the molten material.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Non-Newtonian Fluid Mechanics - Volume 222, August 2015, Pages 96-103
Journal: Journal of Non-Newtonian Fluid Mechanics - Volume 222, August 2015, Pages 96-103
نویسندگان
Jorge Silva, Ricardo Andrade, Rongzhi Huang, Jia Liu, Mark Cox, João M. Maia,