Pulsed-addition ring-opening metathesis polymerization: catalyst-economical syntheses of homopolymers and block copolymers.
Pulsed-addition ring-opening metathesis polymerization: catalyst-economical syntheses of homopolymers and block copolymers.
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DOI：
10.1021/ja809081h
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发表时间：
2009-03-11
影响因子：
15
通讯作者：
Grubbs RH
中科院分区：
文献类型：
--
作者：
Matson JB;Virgil SC;Grubbs RH
通过脉冲 - 增添响环聚合聚合物（PA-ROMP）制备聚（丁基丁基酯NORBORMINE）均聚物和聚（Tert叔丁基酯酯抗酯B-N-甲基氧胺）共聚物。 PA-ROMP是一种独特的聚合方法，它采用对称的顺式烯烃链转移剂（CTA）同时限制活性聚合物链，并以高忠诚度再生ROMP启动器。与传统的连接转移不同，CTA仅与活链端反应，从而导致狭窄的产品。然后，再生引发剂可以启动随后的一批单体的聚合，从而可以从一个金属引发剂中产生具有控制分子量和低多分散性的多个聚合物链。使用快速发射的弦缩ruthenium Methenium catalyst（h2imes）（Cl）2（Pyr）2Ruchph和顺式4-辛烯作为CTA，使用Symyx Robotic System研究了PA-ROMP的功能，该系统允许增加对照和精确的控制和精度注射量。对执行终端限制/引发剂连续步骤所需时间的详细研究的结果用于设计多个实验，其中一个从一个到十个周期进行了PA-romp。确定催化剂死亡的速率后，通过调节每个循环中注射的单体注射量，保持恒定的单体/催化剂比来制备单个低分散性聚合物。此外，通过在第一个单体注入后在特定的时间间隔内快速注入第二个单体，因此使用PA-romp来制备几乎完美的块共聚物，因此尚未发生链条传输。聚合物的特征是凝胶渗透色谱和多角度激光散射。
Poly(tert-butyl ester norbornene imide) homopolymers and poly(tert-butyl ester norbornene imide-b-N-methyl oxanorbornene imide) copolymers were prepared by pulsed-addition ring-opening metathesis polymerization (PA-ROMP). PA-ROMP is a unique polymerization method that employs a symmetrical cis-olefin chain transfer agent (CTA) to simultaneously cap a living polymer chain and regenerate the ROMP initiator with high fidelity. Unlike traditional ROMP with chain transfer, the CTA reacts only with the living chain end, resulting in narrowly dispersed products. The regenerated initiator can then initiate polymerization of a subsequent batch of monomer, allowing for multiple polymer chains with controlled molecular weight and low polydispersity to be generated from one metal initiator. Using the fast-initiating ruthenium metathesis catalyst (H2IMes)(Cl)2(pyr)2RuCHPh and cis-4-octene as a CTA, the capabilities of PA-ROMP were investigated with a Symyx robotic system, which allowed for increased control and precision of injection volumes. The results from a detailed study of the time required to carry out the end-capping/initiator-regeneration step were used to design several experiments in which PA-ROMP was performed from one to ten cycles. After determining the rate of catalyst death, a single, low polydispersity polymer was prepared by adjusting the amount of monomer injected in each cycle, maintaining a constant monomer/catalyst ratio. Additionally, PA-ROMP was used to prepare nearly perfect block copolymers by quickly injecting a second monomer at a specific time interval after the first monomer injection, such that chain transfer had not yet occurred. Polymers were characterized by gel permeation chromatography with multi-angle laser light scattering.
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影响因子：
5.5
作者：
Bielawski, CW;Benitez, D;Grubbs, RH
通讯作者：
Grubbs, RH
影响因子：
--
作者：
Beerens, H;Wang, WJ;Verpoort, F
通讯作者：
Verpoort, F
影响因子：
5.5
作者：
PERROTT, MG;NOVAK, BM
通讯作者：
NOVAK, BM
影响因子：
56.9
作者：
Arriola, DJ;Carnahan, EM;Wenzel, TT
通讯作者：
Wenzel, TT
影响因子：
--
作者：
Mol, JC
通讯作者：
Mol, JC