Dimeric Liquid Crystalline Epoxy Resins Containing Azo Group: Mesogenic Behavior and Curing with Anhydride
A series of dimeric liquid crystalline (LC) epoxy monomers containing azo groups with different length of central spacers were synthesized. The mesogenic behavior of these monomers was characterized by differential scanning calorimetry(DSC), polarized optical microscopy (POM) and wide-angle X-Ray diffraction(WAXS). Like other dimeric LC epoxy monomers, the melting points, clear points and mesophase of these compounds were influenced by the carbon numbers of the central spacers. Cure kinetics of these monomers with anhydride was studied by non-isothermal DSC at different heating rates. With the increasing of conversion, the values of activation energy show a tendency to decrease. The formation and development of LC phase during curing were also studied by POM. Finally LC thermosets with nematic phase were obtained.
Joong Hee Lee
D. W. Zhou et al., "Dimeric Liquid Crystalline Epoxy Resins Containing Azo Group: Mesogenic Behavior and Curing with Anhydride", Advanced Materials Research, Vols. 123-125, pp. 955-958, 2010