A Strategy for Control of "Random" Copolymerization of Lactide and Glycolide: Application to Synthesis of PEG-b-PLGA Block Polymers Having Narrow Dispersity.
A Strategy for Control of "Random" Copolymerization of Lactide and Glycolide: Application to Synthesis of PEG-b-PLGA Block Polymers Having Narrow Dispersity.
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DOI：
10.1021/ma201169z
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发表时间：
2011-09-27
期刊：
影响因子：
5.5
通讯作者：
Hoye TR
中科院分区：
文献类型：
--
作者：
Qian H;Wohl AR;Crow JT;Macosko CW;Hoye TR
聚乳酸-乙醇酸 (PLGA) 是一种可生物降解的共聚物，也可用于各种生物医学应用。通常，无规 PLGA 聚合物是使用锡基催化剂在高温下通过本体间歇聚合合成的。由于酯交换反应，这种方法会产生相对较宽的多分散指数 (PDI)，并且聚合物产品通常会变色。我们在这里报道了使用 1,8-二氮杂双环[5.4.0]-十一碳-7-烯 (DBU) 来合成丙交酯和乙交酯的无规共聚物，DBU 是一种已知、有效且方便的环酯开环聚合有机催化剂。通过核磁共振波谱研究了丙交酯和乙交酯均聚和共聚的聚合动力学。开发了一种新颖的策略，该策略采用受控地将更具反应性的乙交酯单体添加到含有丙交酯单体、聚乙二醇(PEG)大分子引发剂和DBU催化剂的溶液中。使用这种策略（半间歇聚合），我们合成了一系列嵌段共聚物，这些共聚物表现出预期分子量和观察到分子量的良好相关性，并且具有窄 PDI。我们还测量了这些嵌段共聚物的热性能，并观察了基于嵌段共聚物的组成的趋势。我们还探索了制备的几个方面对实验严格性的需求，并确定了一组方便的反应条件，以提供保留上述所需特性的聚合物产品。这些聚合反应在室温下快速进行，无需锡基催化剂即可提供适用于生物医学研究的 PEG-b-PLGA。
Poly(lactic-co-glycolic acid) (PLGA) is a biodegradable copolymer that is also acceptable for use in a variety of biomedical applications. Typically, a random PLGA polymer is synthesized in a bulk batch polymerization using a tin-based catalyst at high temperatures. This methodology results in relatively broad polydispersity indexes (PDIs) due to transesterification, and the polymer product is often discolored. We report here the use of 1,8-diazabicyclo[5.4.0]-undec-7-ene (DBU), a known, effective, and convenient organocatalyst for the ring-opening polymerization of cyclic esters, to synthesize random copolymers of lactide and glycolide. The polymerization kinetics of the homo- and copolymerizations of lactide and glycolide were explored via NMR spectroscopy. A novel strategy that employs a controlled addition of the more reactive glycolide monomer to a solution containing the lactide monomer, the poly(ethylene glycol) (PEG) macroinitiator, and DBU catalyst was developed. Using this tactic (semi-batch polymerization), we synthesized a series of block copolymers that exhibited excellent correlation of the expected and observed molecular weights and possessed narrow PDIs. We also measured the thermal properties of these block copolymers and observed trends based on the composition of the block copolymer. We also explored the need for experimental rigor in several aspects of the preparations and have identified a set of convenient reaction conditions that provide polymer products that retain the aforementioned desirable characteristics. These polymerizations proceed rapidly at room temperature and without the need for tin-based catalysts to provide PEG-b-PLGAs suitable for use in biomedical investigations.
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影响因子：
2.5
作者：
Kreiser-Saunders, I;Kricheldorf, HR
通讯作者：
Kricheldorf, HR
影响因子：
5.5
作者：
Chamberlain, BM;Jazdzewski, BA;Tolman, WB
通讯作者：
Tolman, WB
影响因子：
15
作者：
Li, Jian;Stayshich, Ryan M.;Meyer, Tara Y.
通讯作者：
Meyer, Tara Y.
DOI：
10.1002/pol.1985.170230709
发表时间：
1985-01-01
影响因子：
--
作者：
HUFFMAN, KR;CASEY, DJ
通讯作者：
CASEY, DJ
影响因子：
5.5
作者：
KRICHELDORF, HR;MANG, T;JONTE, JM
通讯作者：
JONTE, JM