Cellulose diacetate grafting poly(caprolactone monoacrylate) copolymers (CDA-g-PCLA) were synthesized by a two-step reaction of cellulose diacetate (CDA) with poly(caprolactone monoacrylate) (PCLA). The isocyanate-terminated intermediate (NCOPCLA) was prepared and grafted onto cellulose diacetate chains. The results of the structure analysis indicated that PCLA was connected to CDA by chemical bonding. The flow temperature of graft copolymers was lower than that of the pure CDA and decreased with increasing the grafting percentage. Outdoor soil burial tests and active sludge tests indicated that the graft copolymers have good biodegradability in natural conditions. (C) 2003 Wiley Periodicals, Inc.