A primary study on the synthesis of polylactone-grafted polyphosphazene copolymers has been carried out for the purpose of using them as cell scaffold material in tissue engineering．It was found that the copolymer could be obtmned via transesterification of hydroxyl-ended polylactone

such as polycaprolactone (PCL) and polylactide (PLA)

with poly[bis(glyeine ethyl ester)phosphazene] (PGP)．However

it was needed to note that this process seemed more suitable for the preparation of PCL-grafted polyphosphazene copolymer than for other polylactone-grafted polyphosphazene copolymers

because the melting point of PCL(ca．60℃) was far below the reaction temperature (160℃)

whichfacilitated the mixing of the two polymers．Moreover

the transesterifieation of PCL with PGP could proceed satisfactorily only if the molecular weight of PCL was less than 8000

which was considered due to the weakened reactivity of hydroxyl end groups with molecular weight increase．Further detailed study is underway to optimize the reaction and it will be focused on the thermostability of poly[(amino acid alkyl ester)phosphazenes] influencing the transesterifieation．