To obtain the subject copolymer comprising a cyclic ketene acetal and a conjugate type monomer and having excellent mechanical properties, water solubility, biocompatibility, biodegradability, etc.
This copolymer comprises a cyclic ketene acetal and a conjugate type monomer, has ester bonds originated from the cyclic ketene acetal in the main chain, having a number-average mol.wt. of ≥20,000, leaves a polymer having a number-average mol.wt. of ≤10,000, when the ester bonds are hydrolyzed, and has a dispersion index of 1.0-5. The cyclic ketene acetal is preferably expressed by formula I [R is CR1R1CR1R1 (R1 is H, a 1-3C alkyl, phenyl or the like), CR1R1CR1R1CR1R1 or the like], and the ester bond is expressed by formula II. The conjugate type monomer is preferably a hydrophobic monomer, and the residual polymer obtained by the hydrolysis preferably has a number- average mol.wt. of 1,000-10,000.
OTA TOSHIHIKO
TANAKA HITOSHI
