Morphologies and mechanical properties of polyarylate liquid crystalline polymer blends compatibilized by a multifunctional epoxy resin

Full Paper: The tetrafunctional epoxy resin, tetraglycidyl-4',4'-diaminodip henyl methane (TGDDM), has been investigated as an efficient reactive compa tibilizer for the blends of polyarylate (PAr) with a liquid crystalline pol ymer (LCP). TGDDM can react with PAr and LCP at the interface simultaneousl y to produce the PAr-co-TGDDM-co-LCP mixed copolymers during melt blending. These copolymers tend to anchor along the interface as the result of the i nterfacial reaction and thus serve as effective compatibilizers to reduce t he interfacial tension and to enhance the interfacial adhesion in the solid state. The morphologies of the PAr/LCP blends were inspected by means of s canning electron microscopy (SEM). It is observed that the dispersed LCP ph ase domains reduce,obviously after compatibilization. Furthermore, it is al so found that the reduced interfacial tension caused by the addition of TGD DM plays a vital role in affecting the deformation of the LCP phase domains in the compatibilized PAr/LCP blends. The LCP phase tends to,deform into g reater numbers and finer fibrils with high aspect ratio after the addition of TGDDM in those blends containing adequate LCP content (>10 %). In the bl end containing low amount of LCP (Par / LCP = 95/5) with high TGDDM content (0.3 phr or higher), however, the LCP phase can only exist as fine but sho rt fibrils or even ellipsoids, The overall mechanical properties of the PAr /LCP blends are substantially improved after compatibilization by this coup ling-type reactive compatibilizer. The generation of LCP fibrils with high aspect ratio and improved interfacial adhesion are the two hinges to enhanc e the performance of the compatibilized PAr/LCP blends.