在丙交酯与聚乙二醇开环共聚的基础上进行了二次聚合,利用具有生物相容性的赖氨酸对聚乳酸/聚乙二醇低聚物进行改性,制备出了赖氨酸改性聚乳酸/聚乙二醇共聚物.通过红外光谱、核磁共振谱、X射线衍射分析仪、差示扫描量热仪、凝胶渗透色谱和接触角测量仪分析比较了聚乳酸、聚乳酸/聚乙二醇和赖氨酸改性聚乳酸/聚乙二醇3种聚合物之间存在的差异.结果表明,实验成功合成了赖氨酸改性聚乳酸/聚乙二醇共聚物;赖氨酸(L-lys)的引入使得共聚物的热焓(ΔH)和熔点(Tm)分别由纯PLLA的81.57 J/g和177.34℃降到46.02 J/g和151.34℃,有效地改善了分子链的柔性和结晶度;聚合物的数均相对分子质量(Mn)也由纯PLLA的7.7×104降到了3.2×104,且相对分子质量分布变宽,但亲水性却得到大幅提高,有望适用于组织工程领域.
Based on ring opening copolymerization of L-lactide (L-LA) and polyethylene glycol 400 (PEG-400),secondary polymerization was carried out using L-lysine with biocompatibility to prepare L-lysine modified poly(lactic acid)/poly(ethylene glycol) copolymers.Obvious differences of PLLA,PLLA-PEG copolymer and L-lysine modified PLLA-PEG copolymer were characterized by FT-IR,NMR,XRD,DSC,GPC and contact angle measurement analysis (CA).The experimental results show that △H and Tm of L-lysine modified PLLA-PEG copolymer synthesized fall from 81.57 J/g and 177.34 C of pure PLLA to 46.02 J/g and 151.34 C respectively,which effectively improve the chain flexibilit and crystallinity.In addition,number-average molecular weight (Mn) of the copolymer decreases gradually from by 7.7 × 104 of pure PLLA to 3.2 × 104,and its dispersivity (Mw/Mn) becomes wider,but the increase of CA makes the hydrophilic higher,which could expect to be applied in the field of tissue engineering.
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