Ring opening copolymerization of succinic anhydride (SA) with ethylene oxide (EO)was successfully carried out by using a series of aluminum-based catalyst in 1

4-dioxane at62±2℃. The results showed that in-situ AlR3-H2O (R=ethyl

iso-butyl) catalysts gavehigher molecular weight (Mw～104)

while Al(OR)3 catalysts gave the higher alternatingcopolymer structure with slightly lower molecular weight. The in-situ AlR3-H2O systems have been evaluated in more detail for the reaction which showed the optimum H2O/Al molar ratio to be 0.5.The copolymers with different composition (FSA/FEO=36/64 to 45/55 mol/mol) were synthesized by using different monomer feed ratio.The melting point(Tm)

glass transition temperature(Tg) and enthalpy of fusion (△Hf) of these copolymers are depended on the copolymer composition and in the range of 87～102℃

-12～-18℃

and 37～66J/g

respectively.The second heating scan of DSC also indicated that the higher alternating copolymer was more easily recrystallized.The onset decomposition temperature was more than 300℃ under nitrogen and influenced by the copolymer composition.