生物降解高分子——聚己内酯/聚氧乙烯/聚丙交酯三元共聚物水解行为的研究

以异辛酸亚锡为催化剂 ,通过聚乙二醇醚 (PEG)引发ε 己内酯和L 丙交酯开环聚合 ,制备了PCL/PEO/PLA三元共聚物 .研究了聚合物在 pH7 4磷酸缓冲溶液、37℃条件下的体外降解行为 .采用GPC、1H NMR、DSC和XRD技术研究了聚合物在水解降解过程中分子量、分子量分布、组成、吸水率、结晶性等的变化 .结果表明共聚物的吸水率随聚醚组分含量而增大 ;随水解材料的失重率增大 ,聚醚组分含量下降程度也加大 .此外研究还表明 :聚合物中丙交酯组分含量高时 ,聚合物的结晶结构主要由PLLA形成 .由于聚合物的水解降解首先发生在无定形区和结晶区边缘 ,随着共聚物的降解、结晶性的PLLA低聚物的生成 ,导致了共聚物的分子量呈双峰分布

STUDY ON BIODEGRADATION BEHAVIOR OF PCL/PEO/PLA TRI-COMPONENT COPOLYMER

Two kinds of PCL/PEO/PLA tri\|component copolymers(PCEL) with different composition were synthesized by direct copolymerization of ε caprolactone, L lactide and PEG(6000) in the presence of stannous octoacte at 130℃ for 56h.The biodegradation behavior of these copolymers was investigated in a pH7 4 phosphate buffer solution at 37±1℃ in vitro .The changes of water sorption,loss weight,molecular weight,molecular weight distribution,thermal properties and composition of the copolymer were monitored by GPC,DSC,XRD and 1H\|HMR techniques.The results showed that the hydrophilicity of the copolymer was enhanced with increasing PEO content,which lead to decrease of the PEO component and increase of the loss weight of the copolymer with degradation time.It was considered that the obtained bi\|modal chromatogram of the GPC profile was attributed to the degradation of the partial crystalline polymer.Since degradation has taken in priorty in amorphous zones and at the edges of crystalline of the polymer,bi\|modal molecular weight distribution of GPC spectrum was formed.This interpretation was supported by DSC and X\|ray diffraction data.