Morphology of a thermotropic random terpolymer liquid crystal polymer crystallized in the bulk: compression mouldings, extrudates and fibres

Abstract

The morphology of extruded pellets, compression and injection moulded articles, and melt spun fibres of a random liquid crystal terpolymer has been investigated. Etching and self-decoration techniques have been used, which reveal a lamellar morphology in bulk samples. The lamellae, ranging from 50 to 1800 Å in thickness depending on the preparation technique, are oriented perpendicular to the fibre or extrusion direction in melt spun fibres and extruded pellets. Extruded pellets are analogous to a composite material with 0.2–1.8 μm diameter ‘fibres’ of the liquid crystal being embedded in a less oriented matrix; greater alignment of the lamellae is observed in the ‘fibres’. The thickness of the lamellae observed in melt spun fibres ranged from 500 to 800 A. Thinner lamellae (50–130 Ǎ) are observed on the surface of compression moulded specimens with thicker (200–1800 Å), presumably extended chain lamellae in the interior. The thickness and degree of alignment, or order, of the lamellae is dependent on the cooling rate. Selected area electron diffraction confirms that the chain axes are perpendicular to the lamellae.