利用酸敏感超支化聚缩醛制备聚乳酸多孔微球  

pH Sensitive Hyperbranched Polyacetals as the Porogen for Preparing Poly(lactic acid) Porous Microspheres

作　　者：陈蕊[1] 罗军[1] 卢毅[1] 於麟[1] 涂克华[1,2] 蒋宏亮[1,2] 王利群[1,2] 

机构地区：[1]浙江大学高分子科学与工程学系 [2]教育部高分子合成与功能构造重点实验室,杭州310027

出　　处：《高分子学报》2014年第6期802-807,共6页Acta Polymerica Sinica

摘　　要：通过缩醛转移聚合合成了一种具有酸敏感特性的超支化聚缩醛(HBPAs),对该聚合物降解行为的研究表明,该聚合物具有很强的酸敏感特性,在pH为5.0时,短时间内可发生迅速的降解,而在pH为7.4时,该聚合物基本不发生降解.利用该聚合物的酸敏感特性,其在弱酸性条件下降解速率远远超过PLA的降解速率,制备了多孔PLA微球.进一步研究发现,通过调控超支化聚缩醛(HBPAs)与PLA的投料比,可以线性调控PLA多孔微球的孔径尺寸,并拟合得到了线性方程.DSC结果以及对微球降解过程的观察表明,在共混微球内部,HBPAs与PLA会发生一定的相分离,使得在酸降解的过程中,更有利于微球内部的HBPAs组分发生降解.In this study hyperbranched polyacetals （HBPAs） were used as a new type of porogens to prepare porous biodegradable microspheres. HBPAs were synthesized through the transacetalization process,which was carried out with an AB2 type monomer of 4-（2-hydroxyethoxy）-benzaldehyde dimethyl acetal and a B2 type core of benzaldehyde dimethyl acetal catalyzed with pyridinium camphorsulfonate （PCS）. The results demonstrated that HBPAs were highly pH sensitive. They degraded rapidly at pH 5.0,and barely degraded at pH 7.4. The porous biodegradable poly（lactic acid） （PLA） microspheres were prepared by blending HBPAs and PLA with the emulsion-solvent evaporation method and the blending microspheres were then placed in acidic conditions for 2 weeks. As HBPAs hydrolyzed faster than PLA,the HBPAs component was first degraded from the blending microspheres to form small pores in the PLA matrix. DSC results and degradation process of the blending microspheres showed that the phase separation appeared in the blending microspheres of HBPAs and PLA. This phase separation favored the hydrolysis of HBPAs in the blending microspheres. The pore size of the microspheres can be regulated by changing the weight ratio of HBPAs to PLA. With increasing the HBPAs amount,the pore size of the PLA microspheres increased in a linear manner. HBPAs, as a new type of porogens,offer a new method to prepare porous microspheres.

关 键 词：超支化聚缩醛 酸敏感 致孔剂 多孔微球 

分 类 号：R318.08[医药卫生—生物医学工程]