PCL-b-PHEAA两亲性嵌段共聚物的制备与表征

Synthesis and Characterization of Amphiphilic Block Copolymer of PCL-b-PHEAA

两亲性嵌段共聚物分子链中含有亲水链段和疏水链段,在组织工程、药物缓释、基因输送等领域有潜在的应用价值,常被用作生物医用材料。通过原子转移自由基聚合(ATRP)在聚己内酯(PCL)分子链中引入亲水性基团,以改善其疏水性能。文中首先制备了聚己内酯大分子引发剂,PCL与2-溴异丁酰溴(BIBB)反应,得到聚己内酯引发剂;再以溴化亚铜为催化剂,2,2-联吡啶为配体,ATRP法引发羟乙基丙烯酰胺(HEAA)聚合,得到两亲性嵌段共聚物。通过核磁共振、红外光谱、凝胶渗透色谱、差示扫描量热分析、扫描电镜、热重分析等方法对共聚物进行表征。结果表明成功合成了PCL-b-PHEAA共聚物,嵌段共聚物在50℃附近发生熔融转变,为致密的层状结构。两亲性嵌段共聚物在选择性溶剂中自组装成胶束,在药物缓释方面有潜在的应用价值。

Amphiphilic block copolymer molecular chains contain hydrophilic segments and hydrophobic segments,in the tissue engineering,drug release,gene delivery and other fields have potential application,which was often used as biomedical materials. The hydrophobic group was introduced into the polycaprolactone（ PCL） molecular chain by atom transfer radical polymerization（ ATRP） to improve its hydrophobic properties. In this paper,PCL and 2-bromoisobutyryl bromide（ BIBB） were prepared to obtain polycaprolactone initiator. The amphiphilic block copolymer was obtained by the polymerization of hydroxyethyl acrylamide（ HEAA） with copper bromide as catalyst and 2,2-bipyridine as ligand. The copolymers were characterized by NMR,IR,GPC,DSC,SEM and TG. The results show that the copolymers PCL-b-PHEAA are successfully synthesized,The block copolymer undergoes a melt transition near 50 ℃,which is a dense layered structure. Amphiphilic block copolymers are self-assembled into micelles in selective solvents and have potential application in drug release.