A series of phosphorus and silica-containing hybrids (DPS) with different molecular weight was synthesized by hydrolysis condensation of intermediate products and various amounts of water.The intermediate was formed by the reaction between 3-glycidyloxypropyltrimethaxysilane (KH-560) and diethyl phosphate (DEP) in different weight ratios.The structure of DPS was determined by Fourier transform infrared (FTIR)

nuclear magnetic spectrum (NMR) and element analysis

while molecular weight and distribution of DPS were measured by gel permeation chromatography (GPC).Then

a cured epoxy resin containing phosphorus and silica-containing hybrid was prepared by the in situ curing of the bisphenon A type epoxy resin and 4

4′-diaminodiphenylmethane with the phosphorus and silica-containing hybrid.The flame retardation was investigated by the limited oxygen index (LOI)

and the thermal properties of the cured epoxy resin were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).Studies on the characteristics of cured epoxy resin containing a phosphorus-and silica-containing hybrid showed that the flame retardant and the thermal properties were enhanced.The flame resistance was indicated by the limited oxygen index in the ranges of 23～29

which was higher than that of the pure epoxy resin (22).The glass translation temperature for E54-Si-3H-20 sample was 204℃ and the temperature of 5% weight loss was about 20℃ higher than that of the pure epoxy resins.Compared to the pure epoxy resin

not only the flame resistance of the cured epoxy resin containing phosphorus

silica-containing hybrid was enhanced

but also the thermal properties were improved.