Blends of Epoxy Resin with Amine-Terminated Polyoxypropylene Elastomer: Morphology and Propreties

摘要

A liquid diglycidyl ether of bisphenol A (DGEBA) epoxy resin is blended in various proportions with amine-terminated polyoxypropylene (POPTA) and cured using an aliphatic diamine hardener. The degree of crosslinking is varied by altering the ratio of diamine to epoxy molecules in the blend. The mixture undergoes almost complete phase separation during cure, forming spherical elastomer particles at POPTA concentraions up to 20 wt%, and a more co-continuous morphology at 25 wt%. In particulate blends, the highest toughness is achieved with nonstoichiomertic amine-to-epoxy ratios, which produce low degrees of crosslinking in the resin phase. In these blends, the correlation between G_IC and plateau modulus (above the resin T_g), over a wide range of amino-to-epoxy ratios, confirms the importance of resin ductility in determining the fracture resistance of rubber-modified thermosets.