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Phase Separation under Shear in Liquid Crystalline Polymer/Polycarbonate Blends

K.-W. Lee, M. R. Kamal and P. K. Chan

Abstract

The effect of low steady shear rates on the phase diagram and phase-separated morphology of liquid crystalline polymer (LCP)/polycarbonate (PC) blends was studied. Experiments were carried out with polarized light microscopy in conjunction with a shear stage for directly monitoring the phase separation behavior of the blends. Phase separation temperatures under shear flow were lower than those observed under quiescent conditions. Consequently, the phase diagram of the blend was shifted to a lower position, relative to the phase diagram obtained under quiescent conditions. The temporal morphological development of phase separation in the blends was also affected by the shear. Phase-separated structures were monitored, with and without shear, in blends containing 50 wt.% LCP. Results showed that the speed and amount of phase separation increased when shear was applied. The results indicate that these blends undergo shear-enhanced phase separation at low steady shear rates.


Mail address: Musa R. Kamal, Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, Quebec, Canada, H3A 2B2 E-mail:

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Received: 2008-10-10
Accepted: 2008-12-05
Published Online: 2013-03-01
Published in Print: 2009-03-01

© 2009, Carl Hanser Verlag, Munich