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Synthesis, processing sand properties of thermotropic liquid‐crystal polymers
Author(s) -
Yoon Hyun N.,
Charbonneau Larry F.,
Calundann Gordon W.
Publication year - 1992
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.19920040311
Subject(s) - thermotropic crystal , materials science , liquid crystal , polymer , composite material , polyester , polyamide , ultimate tensile strength , liquid crystalline , optoelectronics
Thermotropic liquid‐crystal polymers for high‐performance applications are typically based on wholly aromatic polyester and polyamide architectures. The linear character of the aromtic monomers produces polymer chains with stiff, extended conformations. As a result, the chains organize themselves into a nematic melt and readily orient in response to processing flow fields. The close coupling between chain orientation and flow fields produces both a rich variety of materials and a high degree of controllability of their structure and properties (such as the tensile strength, elastic modulus and coefficient of thermal expansion). In this paper, we describe synthetic efforts to develop liquid‐crystal polymer structures and the relationships between chain molecular structure, processing, and properties of this class of polymers in two distinct processing situations: Injection molding and fiber formation. The special importance of the orientational flow field in developing high orientation and excellent mechanical properties will be highlighted.