| Abstract: | In this research, the anionic polymerization of ?‐caprolactam was carried out in the presence of small amounts of several different polyimides to generate polyimide‐g‐nylon 6 copolymers. The polyimides, which were prepared from 2,2′‐bis[4‐(3,4‐dicarboxyphenoxy)phenyl]propane dianhydride and commercially available diamines with a one‐step method, were first dissolved in molten ?‐caprolactam. Phenylmagnesium bromide was then added at 120°C. Under these conditions, caprolactam anions were formed that attacked the five‐membered imide rings to form N‐acyllactam moieties, which activated the anionic polymerization of caprolactam. In essence, nylon 6 chains grew from the polyimide backbones. Probably because of a high activation energy, the process was relatively slow, requiring 1 h at 120°C. The introduction of 5 wt % polyimide into the graft copolymers produced significant increases in the tensile modulus and tensile strength in comparison with those of low‐ and high‐molecular‐weight nylon 6. The elongation to break, however, was reduced. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 292–299, 2006 |
