Synthesis and Biodegradation of the Copolymers of Ethylene Oxide with Various Acid Anhydrides

Ethylene oxide (EO) was copolymerized with two kinds of acid anhydrides, succinic anhydride (SA), and maleic anhydride (MA) or SA and phthalic anhydride (PHA) by ring-opening reaction. MA and PHA were used as the third component, and the changes in biodegradability and physical properties were compared with those of copoly (SA/EO). Molecular weights (Mn) of copolymers were between 24000 and 36000. Biodegradation of the copolymers was evaluated by an enzymatic hydrolysis method. Introduction of a small amount of MA to copoly (SA/EO) increased the biodegradability of the copolymers, in contrast to PHA which decreased the biodegradability slightly. Introduction of the PHA comonomer unit at higher than 10% resulted in the formation of nonbiodegrdable copolymers. In the copoly- (SA/MA/EO) s containing more than 10% of MA, the difference between their non-enzymatic hydrolizability and enzymatic one was insignificant because of their high water solubility.