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The morphology and rheology of polymer blends containing a liquid crystalline copolyester
Author(s) -
Blizard Kent G.,
Baird Donald G.
Publication year - 1987
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.760270909
Subject(s) - copolyester , materials science , rheology , extrusion , polycarbonate , composite material , shear rate , polymer blend , rheometer , polymer , scanning electron microscope , hydroxybenzoic acid , capillary action , morphology (biology) , liquid crystal , copolymer , polyester , organic chemistry , chemistry , optoelectronics , biology , genetics
The morphology of blends of polycarbonate and nylon 6,6 with a copolyester of 60 mole percent p‐hydroxybenzoic acid/40 mole percent poly(ethylene terephthalate) was characterized under different processing conditions. In particular, single‐screw extrusion, steady simple shear flow, and flow through a capillary were studied to determine what conditions were necessary for the development of a fibrillar morphology of the liquid crystalline polymer (LCP). Results indicate that some extensional flow is required for the coalescence and extension of the particulate LCP phase. The viscosity of the blends was determined both in a cone‐and‐plate geometry of a Rheometrics Mechanical Spectrometer at low shear rates and in the Instron Capillary Rheometer at higher rates. In general, only a small (10 or 30 percent) weight fraction of LCP was required to reduce the viscosity of the thermoplastics to that of the polymeric liquid crystal. An attempt was made to correlate the structure of the blends seen under the scanning electron microscope with the observed rheology. Not all aspects of the morphology were possible to explain in terms of the viscous properties of the blends.