THERMAL AND MECHANICAL-BEHAVIOR OF POLYAMIDE-6 POLYAMIDE-61 6T BLENDS/

The thermal and mechanical properties of blends, obtained by mixing po lyamide 6 (PA6) and an amorphous aromatic copolyamide G21 (ISO nomencl ature PA 6I/6T), were investigated by differential scanning calorimetr y, dynamic mechanical analysis, and mechanical tensile tests. Quenched blends show a single glass transition temperature; the T-g-compositio n trend was interpreted by means of the Gordon-Taylor equation. The ha lf-time of crystallization decreases by increasing the G21 content and this indicates a depression of the overall crystallization rate. A sm all decrease in the equilibrium melting temperature of PA6 in the blen ds was observed; this finding suggests that the interaction parameter in PA6/G21 blends is probably very small. The dynamic mechanical analy sis of crystallized blends suggests the presence of a homogeneous amor phous phase even if the crystallization of PA6 occurred. The tensile m echanical properties reveal that G21 acts as stiffener of PA6. The col lected experimental data suggest that PA6 and G21 are miscible in the composition range investigated. (C) 1996 John Wiley & Sons, Inc.