BLENDS OF POLYAMIDE 6 WITH BISPHENOL-A POLYCARBONATE .2. MORPHOLOGY-MECHANICAL PROPERTIES RELATIONSHIPS

The relationships between morphology and mechanical properties in polyamide 6/bisphenol‐A polycarbonate blends have been investigated by means of Scanning Electron Microscopy and tensile tests. The immiscibility of the two polymers gives rise to biphasic blends in which the polycarbonate constitutes the matrix when its concentration is higher than 35 wt %. The morphology of the blends is controlled by the thermal and rheological characteristics, as well as by the mixing conditions. In general, the adhesion at the interface between the phases is absent. Moreover, polycarbonate‐rich blends can be considered as polycarbonate matrix with holes. As a consequence, the blends are mechanically much weaker than the pure components both in terms of Young's modulus and strength, at break. Blends very rich in polyamide, more than 90% by weight, behave differently, probably because of chemical, interchain interactions. This is reflected positively in the impact behavior, which was improved in this composition range. Copyright © 1990 John Wiley & Sons, Inc.