| Epoxy resins(EP)are the most important class of thermosetting matrices used in engineering because of their outstanding adhesion to most surfaces,high mechanical strength,and chemical resistance.They have been used as adhesives,coatings and resin matrices for advanced composites. However,their brittle behavior with low elongation and impact strength restrict the utility for high performance applications.The major concern of this paper is to study the preparation of the EP/PU IPNs on improving mechanical and thermal properties of pure EP were investigated by mechanical test,SEM,TEM,DSC,TGA.And EP/PU IPNs' curing dynamics is researched by using Non-uniform temperature DSC methard.Reaction time and reaction temperature of the PU prepolymer are researched,and obtained the preparation matters concerned temperature for 70℃,the reaction time is 70～90min.Indicated to the polyurethane prepolymer's infrared analysis that the various functional groups are complete reacted,obtained the anticipated product,and discussed the water's influence to the prepolymer.Mechanics test indicated that the mechanical properties of the epoxy resin with polyurethane modificated was strengthened while its toughness improved highly.For the epoxy resin with wt15%-NCO terminated polyurethane modificated,the tensile strength of EP/PU IPNs could increase by 48.1%,the impact strength could increase by 14.9%,which compared with pure epoxy resin.For the epoxy resin with 12%-OH terminated polyurethane modificated,the tensile strength of EP/PU IPNs could increase by23.7%,the impact strength could increase by 78.9%.TG-DSC showed the thermostability of hybrid materials were greatly improved,because the IPNs were formed mutually by polyurethane and epoxy resin,which improved its thermostabilit'y in a wide range.Non-uniform temperature DSC test indicated that,compared with pure epoxy resin,the apparent activation e.nergy of the modified epoxy resin with polyurethane decreased and its activity of curing reaction increased.
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