| The objective of this research was to improve the mechanical properties of nylon 6 through the preparation of poly(imide-g-nylon 6) copolymers. The work was begun with the syntheses of 3,5-bis(4-aminophenoxy)benzoyl caprolactam (DAPBC) and 3,5-diaminobenzoyl caprolactam (DABC). The hydrogenation of the dinitro-substituted precursors to these diamines was carried out at 0;The series of poly(imide-g-nylon 6) copolymers and the polyimide/nylon 6 in-situ blends were characterized with regard to their thermal properties, chemical resistance, moisture resistance, mechanical properties in "dry" and "wet" states, toughness, morphology, and rheology. FTIR, DSC and TEM studies showed that the components in some of the graft copolymers were miscible down to at least 0.5 nm. As the compatibility of the polyimide with nylon 6 increased the copolymer yield strength, tensile strength, modulus, and elongation increased. The moisture resistance of nylon 6 was dramatically increased by the incorporation of only 5 wt% polyimide in the copolymer. The poly(imide-g-nylon 6) copolymers had 5 times the impact strength and 2 times the modulus of nylon 6. Their tensile strengths were 80% higher than that of nylon 6, while their elongations to break were slightly lower. |
