The facile Mannich reaction of phenol, formaldehyde, and polyoxyalkylene polyamines at various molar ratios afforded a family of polyetheramines containing functionalities of phenol, primary amines, secondary amines, and polyoxyethylene or polyoxypropylene block copolymers in the same molecule. The synthesis can be generalized by using various polyoxyethylene or polyoxypropylene diamines (and triamines) of molecular weights ranging from 104 to 430 to prepare a family of Mannich amines, with exception of certain gel products such as phenol/formaldehyde/bis (aminoethyl)ether adduct at 1 : 3 : 3 molar ratio. The series of Mannich amines were evaluated for their epoxy curing reactivities by comparing their gel time and drying time. The Mannich amines prepared from polyoxyethylene amines exhibited higher reactivities than those of polyoxypropylene amine derivatives. The trend of their relative reactivities is explained by the molecular size, the multiplicity of amines in the molecule, and the steric hindrance of amine structure. The physical properties of cured epoxy materials, such as impact, tensile, flexural strength, and hardness properties were also measured and correlated with the amine molecular weight, crosslinking density, and the presence of phenol group. The structure-property relationship is discussed.