LIQUID-CRYSTALLINE EPOXIDE THERMOSETS

Highly ordered networks were produced by copolymerization of a low molecular weight liquid crystalline (LC) diepoxide with an aromatic diamine. A series of aromatic diamines was synthesized and their Polymerization reaction with the LC-diepoxide was studied by means of differential scanning calorimetry. By adjusting the melting point of the crosslinking agents an eutectic LC mixture was found on which all the physical measurements were carried out. The degree of order of a certain dye guest in the polymer networks as determined by UV-dichroism was 0.76. Birefringence measurements have confirmed that about the same level of ordering can be maintained up to the thermal degradation point (i.e., 300 degrees C). Microscopy and X-ray studies have revealed that the epoxy-amine mixture is transformed from a nematic to a smectic phase, as a result of the polymerization reaction at 120 degrees C.