Heteroarm Star-Branched Block Copolymers

杂臂星形支化嵌段共聚物

• 批准号: 8706166
• 负责人: Roderic Quirk
• 金额: $ 45万
• 依托单位: University of Akron
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-07-15 至 1990-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8706166&HistoricalAwards=false
• 关键词: Heteroarm; Star; Branched; Block; Copolymers

Heteroarm star polymers contain n arms, of which x arms are comprised of monomer A while n-x arms are comprised of monomer B. These star-shaped polymers are organic materials of entirely new chemical structure. Recent theoretical work predicts they will exhibit unusual segregation and interphase phenomena. Synthetic procedures will be developed for preparation of these new materials with n = 3,4 with precisely defined architectures and for the attachment of special functional groups at the free ends of the B arms. The consequences of interarm interactions in isolated heteroarm stars will be assessed from the rates and equilibrium for macrocyclization, as deduced from excimer emission by molecules in which two arms bear pyrene at their free ends. Discrimination among the various types of interarm interactions that can occur in semidilute solution, melts, and in the solid state will be determined with heteroarm stars selectively labelled for study of excimer emission or the rate of nonradiative singlet-energy transfer. The dynamics of isolated heteroarm stars, as well as their diffusion in concentrated solutions and melts, will be determined using pulsed-gradient spin-echo nuclear magnetic resonance.

杂臂星形聚合物含有n个臂，其中x个臂由单体A组成，n-x个臂由单体B组成。这些星形聚合物是全新化学结构的有机材料。 最近的理论工作预测它们将表现出不寻常的偏析和相间现象。 将开发合成程序来制备这些具有精确定义的结构的 n = 3,4 新材料，并在 B 臂的自由端附着特殊官能团。 孤立的异臂星中臂间相互作用的后果将从大环化的速率和平衡来评估，如从两个臂在其自由端带有芘的分子的准分子发射推导出来的。 半稀溶液、熔体和固态中可能发生的各种类型的臂间相互作用的区别将通过选择性标记的异臂星来确定，以研究准分子发射或非辐射单线态能量转移的速率。 孤立的异臂星的动力学，以及它们在浓溶液和熔体中的扩散，将使用脉冲梯度自旋回波核磁共振来确定。