Morphology and Tensile Properties of Polycarbonate-Polyethylene Alloy in Phase Inversion Region

Abstract

The phase inversion region of polycarbonate-polyethylene (PC-PE) alloy was experimentally a range between about 45 and 55% PC concentration by weight, quite different from theoretical prediction. The morphological structures were very different between the alloy with PC particles dispersed in PE matrix and that with PE domains in PC continuous phase. The PC particles in PE matrix were sphere and ellipsoid shaped particles, which were embedded tightly by the matrix. However, the PE domains in PC matrix were mainly ellipsoids and rods, and there were voids between the particles and the matrix. Moreover, the PC particles in PE held their original shape, whereas the PE particles were split into two halves when the PC-PE alloy was brittlely fractured in liquid nitrogen. In the curves of the tensile properties of the alloy as a function of PC concentration, a sharp increase was found from 40 to 55 wt.% of PC content. However, the tensile strength and modulus of the alloy with lower or higher than PC content in inversion region were increased slightly with PC concentration in the entire PC composition range tested. Moreover, the experimental data of the tensile modulus are generally in agreement with the result from the Tagayanagi equation for the polymer alloy with perfect interfacial adhesion, where the rule of additivity average based on the Tagayanagi equation was used to calculate the modulus values of the alloy in cocontinuous structure which can not be calculated from the Takayanagi equation.