Properties of E-51/DDS epoxy resin toughened by alkaline EP_b-POSS

The bisphenol A epoxy resin (E-51) / 4,4'- diaminodiphenyl sulfone (DDS) was modified by the epoxy silsesquioxane (EP_b-POSS), which was synthesized by hydrolytic condensation of (γ-glycidoxypropyl)trimethoxysilane under basic condition, to prepare EP_b-POSS/E-51/DDS modified resin systems. The curing process and the influence of EP_b-POSS with different contents on the mechanical properties and thermal stability of the modified resin systems was studied. The results show that although the EP_b-POSS have little effect on the curing process and the stiffness of the modified resin, it can significantly improve the toughness; when the mass fraction of EP_b-POSS is 1.0%, the impact strength of the modified resin can reach 49.2kJ·m², is increased by 90.0%, and shows obvious toughness fracture; the bending strength is 132.8MPa, is slightly increased; and the initial decomposition temperature is 378.0℃, is increased by 26.0℃.