Effect of nano-fillers on curing kinetics and thermal property of liquid crystalline epoxy resins with long chain substituents

A series of nanofillers/liquid crystalline epoxy composites with different nano-fillers were prepared. The curing reaction and phase behavior of 2,5-bis benzoic acid hexanol ester (EP-6)-4,4'-diaminodiphenyl methane (DDM) system were studied by non-isothermal DSC, POM and XRD. The thermal property of the nano-fillers/EP-6-DDM composites was characterized by TGA. It was found that in all the four nano-fillers catalyzed the curing of EP-6-DDM system. SiO₂ has the highest catalytic reactivity and organoclay cloisite 30B has the lowest. The XRD data indicated that only exfoliated nanocomposites formed when the mass fraction of 30B is below 1%, while both exfoliated and intercalated nanocomposites formed when the content of 30B is above 3%. Polarizing optical microscope observation showed that the nano-fillers did not change the nematic structure of resin matrix, but retarded the appearance of nematic texture. Thermogravimetric analysis indicated that the thermal stability of cured nano-fillers/EP-6-DDM decreased slightly.