Effects of convergent flow on in situ fibrillation of TLCP in PEN

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

Detail(s)

Original languageEnglish
Pages (from-to)1505-1513
Journal / PublicationJournal of Applied Polymer Science
Volume91
Issue number3
Publication statusPublished - 5 Feb 2004
Externally publishedYes

Abstract

A polymer melt entering a capillary die from a cylinder undergoes a convergent flow in which there is a complex combination of extensional and shear flows. The convergent flow plays an important role in controlling the in situ fibrillation of thermotropic liquid crystalline polymer (TLCP) in a thermoplastic matrix melt. This study examines effects of the convergent flow on development of TLCP fibrils in a TLCP/poly(ethylene naphthalate) (PEN) blend. A capillary rheometer was used and the extent of the convergent flow was varied by changing capillary dimension and shear rate. With a given capillary die, the TLCP fibrillation was found to increase with increasing shear rate because of the increased deformation of TLCP droplets. The establishment of a fully developed shear velocity profile by using a relatively long die is considered to be necessary to retain the TLCP fibrils initiated in the convergent flow region. At a given high shear rate TLCP fibrillation improves with increasing capillary diameter (≤2 mm) because of the increased difference in velocity between the capillary and the cylinder.

Research Area(s)

  • Blends, Liquid-crystalline polymers, Polyesters, Shear

Bibliographic Note

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Citation Format(s)

Effects of convergent flow on in situ fibrillation of TLCP in PEN. / Li, L.; Chan, C. L.; Yue, C. Y. et al.
In: Journal of Applied Polymer Science, Vol. 91, No. 3, 05.02.2004, p. 1505-1513.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review