生物可降解聚磷腈接枝聚酯共聚物的合成和表征

初步探索了利用酯交换方法制备聚磷腈接枝聚酯共聚物的可能性 .实验发现 ,利用聚酯的端羟基与甘氨酸乙酯全取代的聚磷腈进行酯交换反应 ,是可以获得聚磷腈接枝聚酯共聚物的 .但这种制备过程 ,不仅要求聚酯材料的热稳定性相对较好 ,以及融体粘度较低 ,还要求氨基酸酯取代聚磷腈的热稳定性较好 ,才能获得比较满意的结果 .因此此法更适宜于制备聚磷腈接枝聚己内酯共聚物 ,而且聚己内酯的分子量不宜超过 80 0 0 .

SYNTHESIS OF BIODEGRADABLE POLYLACTONE-GRAFTED POLYPHOSPHAZENE COPOLYMERS

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 obtained via transesterification of hydroxyl ended polylactone,such as polycaprolactone (PCL) and polylactide (PLA),with poly\bis(glycine 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℃),which facilitated the mixing of the two polymers. Moreover,the transesterification 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 transesterification.