Crystallization from Single-Phase Mixtures of Nylon 6 and Aromatic Polyamide

An aliphatic polyamide, nylon 6 (Tm=215°C, Tg=48°C), was found to be miscible with an aromatic polyamide, [CO (CH2) 4CONH-CH2-_??_-CH2-NH] n (MXD6; Tm=233°C, Tg=75°C), and crystallization from a single phase melt was studied by polarized light microscopy, light scattering, and wide angle X-ray diffraction. The crystallization did not yield co-crystals. At a high crystallization temperature (Tc=200°C) near the melting points, MXD6 cryatallized first and then nylon 6 followed. At a low Tc, close to Tg, the constituent polymers simultaneously crystallized, suggesting the diffusion-controlled kinetics.