Morphology of liquid crystalline epoxy composite matrices based on the diglycidyl ether of 4,4′-dihydroxy-α-methylstilbene

Abstract The morphologies of various diglycidyl ethers of 4,4′-dihydroxy-α-methylstilbene-based liquid crystalline epoxy (LCE) formulations have been studied as matrices for high performance composites. Reflected light optical microscopy, selected area electron diffraction, micro-Raman spectroscopy and transmission electron microscopy of thin sections and replicas of etched surfaces were employed to probe both the micrometer-scale and nanometer-scale LCE morphology in infusion moulded, uni-weave graphite fibre composites. The results suggest that various sizes and shapes of LCE domains can be formed in the matrix resin, depending on the cure schedule and the LCE curative composition. Preferred molecular orientation along the graphite fibres can be achieved if the LCE resin is cured so as to promote extensive linear chain extension, thus 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.