A new kind of nonionic active waterborne epoxy resin emulsifier (PEGF51) containing hydrophilic polyether segment was synthesized by using novolac epoxy resin (F51) and α-methoxy-ω-N-isopropanol-para-phenylmethylamino polyethylene glycol. PEGF51/F51 emulsions were prepared via F51 emulsified by the PEGF51 with a phase inversion technique. The structure of the PEGF51 was characterized by IR spectroscopy and gel permeation chromatography (GPC). The average diameter of PEGF51/F51 emulsions, the mechanical properties, impact fractured surfaces and water absorption of the D230-PEGF51/F51 cured products were investigated as function of PEGF51 concentration. The results show that the active epoxy resin emulsifier is available by incorporating the poly(ethylene glycol) segments into the epoxy molecular structure via the chemical linkage with F51, beneficial for increasing hydrophilicity and strain relax rates. When increasing the concentration of PEGF51, the average diameter of dispersed phase particles decreased from 197.0 to 20.9 nm. The glass transition temperature, the room-temperature Young's modulus and tensile strength of the cured products decreased while toughness and elongation increased. Consequently, the D230-PEGF51/F51 cured product with excellent tensile strength, modulus, impact strength and low water absorption at room temperature was obtained when the mole ratio of PEGF51 to F51 was 1∶3.

Key words: waterborne epoxy resin, nonionic type, chemical modification, phase inversion emulsification, active emulsifier