Slit die flow measurements of a liquid crystalline polyesteramide and its blends with polyarylate
作者:
Ane Zaldua,
Eudenia Muñoz,
Juan J. Peña,
Anton Santamaria,
期刊:
Polymer Engineering&Science
(WILEY Available online 1992)
卷期:
Volume 32,
issue 1
页码: 43-48
ISSN:0032-3888
年代: 1992
DOI:10.1002/pen.760320108
出版商: Society of Plastics Engineers
数据来源: WILEY
摘要:
AbstractA commercial thermotropic polyesteramide and its blends with polyarylate are the object of a slit die flow rheological study. The measurements are carried out at 280°C, a temperature slightly above the melting temperature of the thermotropic, covering a shear rate range 10−1s−1to 102s−1. Except in the case of the thermotropic polymer, the pressure profiles are upward parabolic which is attributed to the dependence of the viscosity on pressure. The most striking result is the observed downward curvature in pressure profiles obtained for the liquid crystalline polyesteramide: no explanation is given for this phenomenon, for the present. The elasticity of the polymer melts is expressed in terms of the exit pressure and the extrudate swell. The thermotropic polyesteramide presents negative values of both parameters (e.g. samples shrink instead of swell). Viscosity and elasticity present negative deviation from linearity when plotted against composition; this reduction in the rheological functions, caused by the addition of liquid crystal, is more pronounced at high shear
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