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Polymer Engineering and Science,
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Society of
Plastics Engineers, Inc. on September 1, 1995. The length of the article is 4478 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available in your Amazon.com Digital Locker immediately after purchase. You can view it with any web browser.
From the author: Blends of a poly(ethylene 2,6-naphthalate) (PEN) and a liquid crystalline copolyester (LCP), poly(benzoate-naphthoate) were prepared in a twin-screw extruder. Specimens for thermal properties were prepared by injection molding. Rheological properties and morphology were investigated by means of an Instron capillary rheometer (ICR) and scanning electron microscopy (SEM). The blend viscosity showed a minimum at 10 wt% of LCP and increased with increasing LCP content above 10 wt% of LCP. Above 50 wt% of LCP and at higher shear rate, phase inversion occurred and the blend morphology was fibrous and similar to pure LCP. The ultimate fibrillar structure of LCP phase appeared to be closely related to the extrusion temperature. By employing a suitable deformation history, the LCP phase may be elongated and oriented such that a microfibrillar morphology can be retained in the solid state. Thermal properties of the LCP/PEN blends were studied using DSC and a Rheovibron viscoelastometer. These blends were shown to be incompatible in the entire range of the LCP content. For the blends, the [T.sub.g] and Tm were unchanged. The half time of crystallization for the LCP/PEN blends decreased with increasing LCP content. Therefore, the LCP acted as a nucleating agent for the crystallization of PEN. The dimensional and thermal stability of the blends were increased with increasing LCP content. In studies of dynamic mechanical properties, the storage modulus (E[prime]) was improved with increasing LCP content and synergistic effects were observed at 70 wt% of LCP content. The storage modulus for the LCP/PEN 70/30 blend is twice that of PEN matrix and exceeded pure LCP.
Citation DetailsTitle: Rheology and thermal properties of liquid crystalline copolyester and poly(ethylene 2,6-naphthalate) blends.
Author: Bong Shik Kim
Publication:Polymer Engineering and Science (Refereed)
Date: September 1, 1995
Publisher: Society of Plastics Engineers, Inc.
Volume: v35
Issue: n18
Page: p1421(12)
Distributed by Thomson Gale.
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