MODIFICATION OF NYLON-6 WITH SEMI-AROMATIC OR WHOLLY-AROMATIC POLYAMIDES

In this study, flexible Nylon-6 was reinforced by semi- or wholly-arom atic polyamides; poly(m-phenylene isophthalamide) (PmIA), poly(4,4'-di phenylmethane terephthalamide) (PMA), and poly(4,4'-diphenylsulfone te rephthalamide) (PSA). Various high molecular weight block copolyamides were synthesized by solution polymerization using p-aminophenylacetic acid (p-APA) as a coupling agent. Their thermal properties have shown that the block copolyamides exhibit higher T-g and T-m, and better th ermal stability than those of Nylon-6, especially PmIA modified Nylon- 6. The order of their thermal properties of aromatic modified Nylon-6 copolyamides is PmIA > PMA > PSA. Moreover, the T-g and T-m of multibl ock copolyamides are higher than those of triblock copolyamides. From the wide-angle X-ray diffraction pattern, it is found that the tribloc k copolyamides have two diffraction peaks, i.e., 2 theta = 20.5 degree s and 24 degrees. However, the multiblock has only one peak at 2 theta = 20 degrees, indicating a different crystal structure for multiblock copolyamides. For the mechanical properties, it is found that the mul tiblock copolyamides have a more significant reinforcing effect than t he triblock copolyamides. Also, the order of the physical properties o f aromatic modified Nylon-6 copolyamides, such as tensile strength, is PmIA > PMA > PSA, but for the elongation PSA > PMA > PmIA.