Storable, Dual-Component Systems for Frontal Ring-Opening Metathesis Polymerization,Macromolecules

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Storable, Dual-Component Systems for Frontal Ring-Opening Metathesis Polymerization
Macromolecules ( IF 5.1 ) Pub Date : 2022-06-16 , DOI: 10.1021/acs.macromol.2c00775
Benjamin A. Suslick _{1,

2} , Aliza N. Yazdani _{1,

2} , Morgan M. Cencer _{1,

2} , Justine E. Paul _{1,

3} , Nil A. Parikh _{1,

4} , Katherine J. Stawiasz _{1,

2} , Isabel P. S. Qamar _{1,

3} , Nancy R. Sottos _{1,

3} , Jeffrey S. Moore _{1,

2}

Affiliation

Frontal ring-opening metathesis polymerization (FROMP) catalyzed by Grubbs-type Ru complexes enables new, rapid, and energy-efficient syntheses of high-performance, structural plastics. Ideal catalysts survive the extended time periods associated with resin preparation, storage, and transportation. Current catalysts, however, induce premature polymerization within hours to days under ambient conditions. In this work, a thermally latent bis-N-heterocyclic carbene complex provides exceedingly robust resins, which are viable for 8 weeks. When mixed with Cu^I coreagents, precatalyst activation primes the system for rapid reactivity after thermal initiation. In this study, more than 40 dual-component formulations successfully catalyzed FROMP of dicyclopentadiene. The polymerization process parameters (front temperatures and velocities), resin storability, and resultant polymer properties (e.g., T_g) were determined for each composition. Intriguingly, the Cu to Ru ratio dramatically impacts the observed frontal velocity and temperature, as well as the polymer glass-transition temperature; slower, colder reaction fronts result from formulations with large Cu to Ru ratios. The resultant polymers display lower T_g values. Mechanistic analysis of a related model system demonstrated that an excess Cu reagent decreases the activation and polymerization rates.

中文翻译：

用于正面开环复分解聚合的可储存双组分系统

由 Grubbs 型 Ru 配合物催化的正面开环复分解聚合 (FROMP) 可实现新型、快速和节能的高性能结构塑料合成。理想的催化剂能够经受与树脂制备、储存和运输相关的延长时间。然而，目前的催化剂在环境条件下会在数小时至数天内引发过早聚合。在这项工作中，一种热潜伏的双-N-杂环卡宾配合物提供了非常坚固的树脂，可使用 8 周。与 Cu ^I混合时助剂，催化剂前活化使系统在热引发后快速反应。在这项研究中，40 多种双组分配方成功地催化了双环戊二烯的 FROMP。_测定每种组合物的聚合工艺参数（前沿温度和速度）、树脂可储存性和所得聚合物性能（例如，T g ）。有趣的是，Cu 与 Ru 的比例会显着影响观察到的正面速度和温度，以及聚合物的玻璃化转变温度；较慢、较冷的反应前沿是由具有大 Cu 与 Ru 比率的配方产生的。所得聚合物显示较低的T _g价值观。相关模型系统的机理分析表明，过量的 Cu 试剂会降低活化和聚合速率。

更新日期：2022-06-16

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