Fourteen MC nylons (polycaprolactam) modified by three aromatic compounds containing quinoxaline ring were prepared. Their morphology

impact strength

water absorbency and melting behaviour were characterized. The introduction of the mono-model compound of poly-phenylquinoxaline(PPQ) has little effect on the crystallization of MC nylon. The addition of small amounts of phenazine (0.005-5.0%) induced a great change of color

morphology and properties of MC nylon. The modification effect was considered to result from the bydrogen bond between nylon-6 and phenazine. The effect of the di-model compund of PPQ on MC nylon is between that of he mono-model compound and phenazine.