Abstract:

This paper introduces a modification technology of 3238 mediumtemperature curing epoxy resin with aromatic diamine. The infection to epoxy resin curing cycle and forming process is avoided by the prereaction of aromatic diamine and epoxy resin bisphenol A. The difference of the differential scanning calorimetry(DSC) onset (Ti) and top (Tp) temperature is only 3℃. The difference of the final curing degree is 1%. The hygrothermal properties of resin 3238 are improved because of the introduction of the rigidity structure of aromatic diamine and its higher crosslinking density than that of dicyandiamide and epoxy resin.The moisture absorption of the resin is decreased by 0.34%,and the dry and wet glass transition temperature is increased by 29℃ and 46℃ respectively.Toughness is retained because of the forming of a high and low crosslinking density section.The tensile stress-strain curve exhibites clear plastic deformation and its elongation reaches 5.31%.The model II fracture toughness of the composite reaches 1 133 J/m².

Key words: composites,  , epoxy , resin,  , modification,  , hygrothermal , property,  , toughness