Morphology and properties of compatibilized ternary blends (nylon 6/a thermotropic liquid crystalline polymer/a functionalized polypropylene) processed under different conditions

Relationships between the properties of ternary blends of nylon 6, a thermo tropic liquid crystalline polymer (TLCP, poly(ester amide), 20 wt%) and a c ompatibilizer (maleic-anhydride-grafted polypropylene, MA-PP, 2 wt%) are st udied under various processing conditions. The immiscible binary blend can be compatibilized by the addition of MA-PP. The compatibilizer provides ext rudate surface stability, thus enabling high drawing. Strong elongational f low, which was not possible when maleic-anhydride-grafted ethylene-propylen e-diene terpolymer was used as a compatibilizer, favors fibril development. The shear viscosity of the ternary blend is slightly lower than that of th e binary blend. The morphology of the dispersed TLCP phase varies between d roplets and oriented fibrils when the drawing is weak and is highly correla ted with changes in tensile properties. The optimum die exit temperature (2 80 degrees C) provides a more uniform morphology and more fibril shapes whi ch are associated with the increased tensile properties. The die exit tempe rature effect still exists when the draw ratio is high. In all cases, it is manifest that, whenever applicable, extension is a decisive factor in the deformation of the dispersed TLCP droplets, which is necessary for signific ant improvements in the mechanical properties. (C) 1999 Published by Elsevi er Science Ltd. All rights reserved.