Comparison of the Properties of Thermotropic Liquid Crystalline Polymer Nanocomposites with Organically Modified Montmorillonites

A thermotropic liquid crystalline polymer (TLCP) nanocomposite was synthesized via in-situ intercalation polymerization of 4-(4-acetoxy-1,4-phenyleneoxytetramethyleneoxy)benzoic acid, which was newly synthesized in the presence of organoclay. Organoclay was prepared by the cation exchange reaction of sodium-montmorillonite (Na+- MMT) with a solution of the ammonium salt of ethyl-4-aminobenzoate (EAB). Ethyl-4-aminobenzoate-montmorillonite (EAB-MMT) and Cloisite (R) 30B were used in the formation of TLCP hybrids. The thermal properties, morphologies, and liquid crystalline phases of TLCP hybrids with two different organoclays were compared. The addition of only a small amount of organoclay was sufficient to improve the thermal properties of the TLCP hybrids. Even polymers with low organoclay content (1-9 wt%) were found to exhibit much higher glass transition temperature (TO, melt transition temperature (T-m), and initial decomposition temperature (T-D(i)) values than those of pure TLCP. The addition of EAB-MMT was more effective than that of Cloisite (R) 30B in improving the thermal properties. The intercalation of the polymer chains in the clays was examined by wide-angle X-ray diffraction (XRD) and transmission electron microscopy (IEM).