Structural characterization and related properties of EP/LCP blends

Blends of (ethylene-co-propylene) and a thermotropic liquid crystalline polymer (LCP) have been prepared by melt mixing technique. Microstructure of the blends has been studied by XRD and SEM. Thermal properties and dynamic behavior of the composites have been analyzed by DSC/TGA and DMTA respectively. The crystallinity decreases with the increase in LCP content. At lower level of LCP in composites (up to 20%), a growth in crystallinity is favored. From DMTA it has been observed that at higher loading of LCP, the relaxation peaks shift to a higher temperature. The changes of storage modulus, loss modulus and stiffness as a function of blend ratio have suggested the phase inversion at the 50% level of LCP in the blend. From DSC it has been shown that thermal stability increases with increasing LCP content in the composites. The decreasing heat of fusion supports the finding of a change in crystallinity of the blends. Under dynamic conditions the matrix flow was restricted with the increase of LCP content and hence cracks developed at the interface of the glass fibre and matrix.