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An in‐process ultrasonic approach to investigating the relaxation of orientation and disorientation of polymer melts
Author(s) -
Li Jiang,
Sun Zhigang,
Tatibouët Jacques,
Jen ChengKuei
Publication year - 2008
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.21023
Subject(s) - materials science , polypropylene , melt flow index , ultrasound , polymer , composite material , shear rate , ultrasonic sensor , capillary action , relaxation (psychology) , shear (geology) , rheometer , rheology , acoustics , psychology , social psychology , physics , copolymer
The orientation and relaxation behaviors of a low‐density polyethylene melt and polypropylene melts with different melt indices undergoing a shear flow in a restricted channel were investigated by using ultrasound. A capillary rheometer was used to force the polymer melt through a slit die equipped with pressure, temperature, and ultrasound sensors, and the variation of ultrasound velocity traversing the melt was measured. Experimental results revealed that due to different mechanisms involved, the relaxations of orientation and disorientation processes show different dependences of ultrasound velocity on shear rate, temperature, and melt index. POLYM. ENG. SCI., 2008. Published 2008 Society of Plastics Engineers