One-pot synthesis of methacrylic acid-ethylene oxide branched block and graft copolymers
One-pot synthesis of methacrylic acid-ethylene oxide branched block and graft copolymers
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DOI：
10.1039/b612226d
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发表时间：
2007-01-01
影响因子：
--
通讯作者：
Sherrington, David C.
中科院分区：
文献类型：
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作者：
Graham, Susan;Rannard, Steve P.;Sherrington, David C.
尽管有大量关于嵌段共聚物的合成和物理化学表征及其在各种各样的产品中的应用潜力的学术文献，但这些材料中相对较少被商业化。这方面的主要障碍往往是合成成本高，而潜在产品的附加值高。因此，设计更经济有效的嵌段共聚物路线仍然是聚合物化学家的一个重要挑战。使用传统的溶液自由基聚合，我们现在已经合成，每一个在一锅，结构复杂的“支化二嵌段共聚物”和组成相关的“接枝支化共聚物”，利用一个通用的支化合成方法在我们自己的实验室开发。在每种情况下，涉及聚（甲基丙烯酸）和聚（乙二醇）（PEG）的嵌段。第一组通过甲基丙烯酸与PEG二甲基丙烯酸酯的共聚获得，所述PEG二甲基丙烯酸酯具有通过使用适当水平的自由基链转移剂在与交联的竞争中有利的支化。对于第二系列，甲基丙烯酸已与PEG单甲基丙烯酸酯和乙二醇二甲基丙烯酸酯共聚，再次通过使用链转移剂抑制交联。获得了良好的产物产率，并且通常选择聚合摩尔进料组成以在共聚物中产生聚（甲基丙烯酸）和PEG嵌段的均匀质量平衡，尽管该参数是容易调节的。已通过元素微量分析和H-1 NMR光谱，后者还结合多角度光散射尺寸排阻色谱（MALS/SEC）的摩尔质量数据，以提供信息的分支结构的产品的分子组成。产物在结构和摩尔质量方面都是复杂的混合物，但合成策略比通过多步活性聚合程序获得结构更均匀的类似物的替代路线要简单得多，更实用，更具成本效益。因此，这些材料与这些类似物是互补的，而不是竞争的。本方法有助于有效扩大规模，并可使大量材料随时可用于进一步的物理化学表征和应用评价。
Despite the large volume of academic literature on the synthesis and physico-chemical characterization of block copolymers and their potential for application in a wide variety of products, relatively few of these materials have been commercialized. More often than not the main obstacle to this is the high cost of synthesis versus the extra value added to potential products. Devising more cost-effective routes to block copolymers therefore remains an important challenge to polymer chemists. Using conventional solution free radical polymerization we have now synthesized, each in one-pot, architecturally complex 'branched diblock copolymers' and compositionally related 'grafted branched copolymers', exploiting a generic branching synthetic methodology developed in our own laboratory. In each case blocks of poly(methacrylic acid) and poly(ethylene glycol) (PEG) are involved. The first group was obtained by copolymerization of methacrylic acid with a PEG dimethacrylate with branching favoured in competition with crosslinking by use of appropriate levels of free radical chain transfer agent. For the second series methacrylic acid has been copolymerized with a PEG monomethacrylate and ethylene glycol dimethacrylate, again with crosslinking inhibited by use of a chain transfer agent. Good yields of products are obtained and typically the polymerization mole feed compositions have been chosen to yield an even mass balance of poly(methacrylic acid) and PEG blocks in the copolymers, though this parameter is readily adjustable. The molecular composition of the products has been characterized by elemental microanalysis and H-1 NMR spectroscopy, with the latter also combining with multi-angle light scattering size exclusion chromatographic (MALS/SEC) molar mass data to provide information on the branching architecture. The products are complex mixtures in terms of both architecture and molar mass, but the synthetic strategy is far simpler, more practical and more cost-effective than alternative routes to structurally more uniform analogues via multi-step living polymerization procedures are likely to be. The materials are therefore complementary to, rather than competitive with, these analogues. The present approach lends itself to efficient scale-up, and could make significant quantities of materials readily available for further physico-chemical characterization and applications evaluation.