Synthesis and thermal responsive properties of P(LA-b-EO-b-PO-b-EO-b-LA) block copolymers with short hydrophobic poly(lactic acid) (PLA) segments
Synthesis and thermal responsive properties of P(LA-b-EO-b-PO-b-EO-b-LA) block copolymers with short hydrophobic poly(lactic acid) (PLA) segments
复制标题
DOI：
10.1016/j.polymer.2005.01.010
复制
发表时间：
2005-02
期刊：
影响因子：
4.6
通讯作者：
X. Xiong;K. Tam;L. Gan
中科院分区：
文献类型：
--
作者：
X. Xiong;K. Tam;L. Gan
将聚乳酸（PLA）成功地接枝到PluronicF 87嵌段共聚物（PEO-PPO-PEO）的两端，得到了具有短PLA嵌段的两亲性P（LA-b-EO-b-PO-b-EO-b-LA）嵌段共聚物（PLA-F87-PLA）。采用核磁共振（NMR）、凝胶渗透色谱（GPC）、差示扫描量热法（DSC）和广角X射线衍射（WXRD）等技术研究了PLA-F87-PLA嵌段共聚物的嵌段组成和结构。采用激光光散射技术研究了PLA-F87-PLA嵌段共聚物在水溶液中的聚集行为。由于共聚物的结构复杂，可观察到由小胶束、中聚集体和大聚集体组成的各种类型的粒子。重要的是，PLA-F87-PLA嵌段共聚物保留了Pluronic系统中发现的热响应行为。PLA-F87-PLA的临界胶束化温度（CMT）低于F87，因为PLA嵌段引入的疏水性增加。由PLA 6-F87-PLA 6和PLA 9-F87-PLA 9嵌段共聚物形成的水凝胶观察到可逆的溶胶-凝胶转变。使用亲水性模型药物盐酸普鲁卡因（PrHy）的药物释放研究的初步结果是有希望的。观察到恒定的初始释放速率。
Poly(lactic acid) (PLA) was successfully grafted to both ends of Pluronic F87 block copolymer (PEO–PPO–PEO) to obtain amphiphilic P(LA-b-EO-b-PO-b-EO-b-LA) block copolymers (PLA–F87–PLA) with short PLA blocks. The block composition and structure of PLA–F87–PLA block copolymers were studied by nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), differential scanning calorimetric (DSC) and wide angle X-ray diffraction (WXRD) techniques. The aggregation behavior of PLA–F87–PLA block copolymers in aqueous solutions was studied using the laser light scattering (LLS) technique. Various types of particles consisting of small micelles, medium and large aggregates were observed due to the complex structure of these copolymers. Importantly, PLA–F87–PLA block copolymers retain the thermal responsive behavior found in Pluronic systems. The critical micellization temperatures (CMTs) of PLA–F87–PLA were lower than that of F87 because of increased hydrophobicity introduced by the PLA blocks. A reversible sol–gel transition was observed for the hydrogels formed from PLA6–F87–PLA6and PLA9–F87–PLA9block copolymers. Preliminary results from the drug release study using a hydrophilic model drug procain hydrochloride (PrHy) were promising. Constant initial release rate was observed.