Development of Thermotropic Polyesters

A history of the industrial development of thermotropic polymers would not be complete without a brief review of preceding technology, that is, the discoveries and developments made in lyotropic polymers. Thus, the timeline of milestones in liquid crystalline polymers proceeds from the initial observation of small molecule liquid crystallinity to the discovery of lyotropic and thermotropic high performance polymers and on through to the recent commercialization of thermotropic polyesters with the introduction of the Vectra (Celanese Corporation) and Xydar (Dartco Manufacturing) families of engineering resins. 

Shown in the table below, the earliest recognition of liquid crystalline behavior, observed on a thermotropic cholesteric small molecule, is attributed to Reinitzer in 1888. In the Forties and Fifties, polymeric liquid crystallinity was noted and widely researched. The systems studied were mostly natural and synthetic lyotropic biopolymers such as 

Copyright 1986 by Elsevier Science Publishing Co., Inc. High Performance Polymers Their Origin and Development R.B. Seymour and G.S. Kirshenbeum, Editors 

LIQUID CRYSTAL RECOGNITION LYOTROPIC BIOPOLYMERS TOBACCO MOSAIC VIRUS -COLLAGEN 

MELT PRXESSABLE WHOLLY AROMATIC POLYESTER -EKKCEL 1-2000 (CARBORUNDUM) 

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This method is attractive, since polymers with good thermal stability are obtained, especially with aryl or halogeno substituents.165 174 Moreover, a number of substituted polyester LCPs exhibit solubility in common organic solvents, thus facilitating their structural characterization. However, the cost of starting monomers has hampered the commercial development of thermotropic polyesters based on substituted monomers. 

In conclusion, the industrial development of thermotropic polyesters was traced through its theoretical origins, the identification of useful compositions, and ultimately to full commercialization of Xydar and Vectra, Commercialization of other thermotropic resins will, in all likelihood, be announced soon, as will high performance fibers made from variants of polymers described herein. 

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