Modification of nylon-6 with wholly rigid poly(m-phenylene isophthalamide)

In this study, the flexible nylon-6 was reinforced by the wholly rigid aromatic polyamide poly(m-phenylene isophthalamide) (PmIA) (Nomex) by physical polyblending and chemical copolymerization using p-aminophenylacetic acid (P-APA) as a coupling agent. From DSC measurements, it was shown that T_g of the polyblends increased with the increase of Nomex content. The T_g and T_m of multiblock copolyamides were found to be higher than those of polyblends and triblock copolyamides. Scanning electron microscopy revealed that the polyblends were a dispersed phase structure, although the multiblock copolyamides exhibited a homogeneous texture rather than an aggregated one. From the wide-angle X-ray diffraction pattern, it was found that the triblock copolyamides and polyblends had two diffraction peaks, i.e., 2 θ = 20.5 and 24°. However, the multiblock had only one at 2 θ = 20°, indicating a different crystal structure for multiblock copolyamides. For the mechanical properties, it was found that the multiblock copolyamides had a more significant reinforcing effect than those of polyblends and triblock copolyamides.