Abstract
Thermotropic liquid-crystalline polyesters are a new class of polymeric materials which have unique molecular and solid-state structures, flow characteristics and mechanical properties. Injection-moulded plaques were found to consist mainly of three highly anisotropic, flow-induced macrolayers: two skins with a core in between. By using fractographic methods, the internal solid-state structure of the macrolayers was elucidated. A hierarchical structure has been proposed describing the observed levels of organization. The skin macrolayer has a distinct structural gradient comprised of three subdivisions from the surface inward: a highly oriented top-layer, several oriented sublayers and a less oriented inner zone. The top layer is fibrillar in nature and the sublayers consist of stacks of interconnected microlayers. In the core, no well-defined substructure was observed, yet molecular orientation perpendicular to the injection direction represented the localized flow patterns.
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Weng, T., Hiltner, A. & Baer, E. Hierarchical structure in a thermotropic liquid-crystalline copolyester. J Mater Sci 21, 744–750 (1986). https://doi.org/10.1007/BF01117348
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DOI: https://doi.org/10.1007/BF01117348