Hindered Urea Bond Based Dynamic Chemistry and Polymer Synthesis

基于位阻脲键的动态化学与聚合物合成

• 批准号: 1508710
• 负责人: Jianjun Cheng
• 金额: $ 22万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-15 至 2017-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1508710&HistoricalAwards=false
• 关键词: Hindered; Urea; Bond; Based; Dynamic

With this award, the Macromolecular, Supramolecular and Nanochemistry Program of the Division of Chemistry is supporting Professor Jianjun Cheng of the University of Illinois at Urbana-Champaign to investigate the reversible bond-forming and bond-breaking processes of a novel type of polymers. Polymers containing reversible dynamic bonds may possess very useful properties such as self-healing, shape memory and environmental adaptation. For example, when there is a crack in the polymeric materials, polymers bearing dynamic bonds may allow self-repairing of the crack and restoration of material?s original mechanical strength. The knowledge gained from this research is disseminated through various endeavors including publications in scientific journals and presentations in summer camp programs and Engineering Open-House at the University of Illinois. This project provides research training opportunity to graduate and undergraduate students, including members of underrepresented groups, in the areas of organic synthesis and polymer chemistry.The reaction of an isocyanate and an amine is one of the most classical reactions in polymer chemistry that allows the preparation of polyurea, an inexpensive, widely used engineering polymer with very stable bulk property. While urea bond is a very robust covalent bond, it can be weakened by the presence of bulky substituent on one of the nitrogen atoms of the urea group because of bond distortion. Hindered urea bonds (HUBs) may undergo both fast association and dissociation reactions. Professor Cheng's group systematically studies the bond association and dissociation properties of various hindered urea structures, optimizes the dynamicity, and explores the properties and applications of HUB-bearing polymers. This work aims to yield polyureas and poly(urethane-urea)s capable of dynamic property change and autonomous repairing at low temperature without catalysts.

有了这个奖项，化学系的大分子，超分子和纳米化学项目正在支持伊利诺伊大学厄巴纳-香槟分校的程建军教授研究一种新型聚合物的可逆键形成和键断裂过程。 含有可逆动态键的聚合物可能具有非常有用的性质，例如自修复、形状记忆和环境适应性。 例如，当在聚合物材料中存在裂纹时，承载动态键的聚合物可以允许裂纹的自修复和材料的恢复。的原始机械强度。 从这项研究中获得的知识通过各种努力传播，包括在科学期刊上发表文章，在夏令营项目和伊利诺伊大学工程开放日上发表演讲。 该项目为研究生和本科生提供了有机合成和高分子化学领域的研究培训机会。异氰酸酯和胺的反应是高分子化学中最经典的反应之一，可以制备聚脲，这是一种廉价，广泛使用的工程聚合物，具有非常稳定的本体性质。 虽然脲键是非常牢固的共价键，但由于键变形，脲基的一个氮原子上存在大体积取代基会削弱脲键。 受阻脲键（HUB）可以经历快速缔合和解离反应。 Cheng教授的团队系统地研究了各种受阻脲结构的键缔合和解离性质，优化了动力学，并探索了含HUB聚合物的性质和应用。本工作的目的是在无催化剂的条件下，制备出能在低温下发生动态性能变化和自修复的聚脲和聚脲-脲。