| In recovery experiments after melt elongation, binary blends of immiscible polymers display large values of the recovered stretch that strongly exceed the recovery of the pure components. This unusual behavior is caused by the interfacial tension: It attempts to minimize the interfacial area between the two phases and thus predominantly promotes the macroscopic retraction of the sample. In this article, the transient recovery of binary blends of immiscible polymers is studied theoretically by applying an effective medium approximation. Numerical solutions of the time evolution equations for the stretch ratio of the sample and of the disperse phase allow quantitative prediction of the recovery of the sample. Our analysis shows that matrix and disperse phase deform with different Hencky strain rates during recovery. The equilibrium value of the recovered stretch and the characteristic time scale of the recovery are functions of the volume concentration Phi of the disperse phase. The equilibrium value of the recovered stretch increases with Phi and with the maximum elongational strain of the sample. Finally we consider the breakup of single droplets and show that Rayleigh instabilities can frequently occur during recovery if the volume concentration Phi remains below an upper limit.
for LaTeX users @article{UAHandge2003-47,
author = {U. A. Handge},
title = {Modeling recovery of polymer blends after melt elongation},
journal = {J. Rheol.},
volume = {47},
pages = {969-978},
year = {2003}
}
\bibitem{UAHandge2003-47} U.A. Handge,
Modeling recovery of polymer blends after melt elongation,
J. Rheol. {\bf 47} (2003) 969-978.UAHandge2003-47
U.A. Handge
Modeling recovery of polymer blends after melt elongation
J. Rheol.,47,2003,969-978 |
mk@mat.ethz.ch
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