Organocatalytic Cationic Ring-Opening Polymerization of a Cyclic Hemiacetal Ester
Organocatalytic Cationic Ring-Opening Polymerization of a Cyclic Hemiacetal Ester
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环状半缩醛酯的有机催化阳离子开环聚合
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
M. Hillmyer
中科院分区：
文献类型：
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作者：
Angelika E. Neitzel;Thomas J. Haversang;M. Hillmyer
我们报告了可再生来源的2-甲基-1，3-二氧杂环己烷-4-酮（MDO）的本体阳离子开环聚合，以产生具有促进降解的水解和热敏感键的聚酯。采用多种质子酸作催化剂，成功地聚合了纯单体。我们发现，这些催化剂，MDO的阳离子聚合进行通过两个不同的机制路线，即，活化单体（AM）和活性链端（ACE）机制。这些竞争机制的途径的动力学进行了研究，采用二苯基磷酸（DPP）与或不与醇引发剂。在没有外源引发剂的情况下，聚合通过二氧碳烯鎓离子进行传播，该离子快速添加更多的MDO以产生高摩尔质量的聚（2-甲基-1，3-二氧杂环己烷-4-酮）（PMDO）。然而，我们发现[MDO]0/[质子酸]0和所得摩尔质量之间没有明确的关系，表明ACE机制没有得到很好的控制。这一结论得到了进一步的支持...
We report the bulk cationic ring-opening polymerization of renewably sourced 2-methyl-1,3-dioxan-4-one (MDO) to yield a polyester with hydrolytically and thermally sensitive linkages that facilitate degradation. Neat monomer was successfully polymerized using a variety of protic acids as catalysts. We discovered that, with these catalysts, the cationic polymerization of MDO proceeds via two distinct mechanistic routes, namely, the activated monomer (AM) and active chain-end (ACE) mechanisms. The kinetics of these competing mechanistic avenues were investigated by employing diphenylphosphoric acid (DPP) with or without an alcohol initiator. Without an exogenous initiator, the polymerization propagates via a dioxacarbenium ion that rapidly adds more MDO to produce high-molar-mass poly(2-methyl-1,3-dioxan-4-one) (PMDO). However, we found no clear relationship between [MDO]0/[protic acid]0 and resultant molar mass, suggesting that the ACE mechanism is not well-controlled. This conclusion was further supported...
影响因子：
5.5
作者：
Qian H;Wohl AR;Crow JT;Macosko CW;Hoye TR
通讯作者：
Hoye TR