MORPHOLOGY OF LIQUID-CRYSTALLINE EPOXY COMPOSITE MATRICES BASED ON THE DIGLYCIDYL ETHER OF 4,4'-DIHYDROXY-ALPHA-METHYLSTILBENE

The morphologies of various diglycidyl ethers of 4,4'-dihydroxy-alpha- methylstilbene-based liquid crystalline epoxy (LCE) formulations have been studied as matrices for high performance composites. Reflected li ght optical microscopy, selected area electron diffraction, micro-Rama n spectroscopy and transmission electron microscopy of thin sections a nd replicas of etched surfaces were employed to probe both the microme ter-scale and nanometer-scale LCE morphology in infusion moulded, uni- weave graphite fibre composites. The results suggest that various size s and shapes of LCE domains can be formed in the matrix resin, dependi ng on the cure schedule and the LCE curative composition. Preferred mo lecular orientation along the graphite fibres can be achieved if the L CE resin is cured so as to promote extensive linear chain extension, t hus giving a high concentration of mesogenic segments. Approaches for aligning mesogenic segments in the composite are discussed as well as the potential benefits of doing so. (C) 1998 Elsevier Science Ltd. All rights reserved.