Packing, Local Order, and Dynamic Processes in Glassy Polymers

玻璃态聚合物中的堆积、局部有序和动态过程

• 批准号: 9729734
• 负责人: Jacob Schaefer
• 金额: $ 36万
• 依托单位: Washington University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-02-01 至 2001-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9729734&HistoricalAwards=false
• 关键词: Packing; Local; Order; Dynamic; Processes

9729734 Schaefer This project involves the combination of solid-state, magic-angle spinning, dipolar-recoupling NMR experiments, with generalized Langevin dynamics simulations, for the characterization of the chain motion of a new generation of engineering polymers. The polymers are based on polycarbonate-like structures that have enhanced mechanical or optical properties. The NMR is used to measure interchain distances that act as constraints on the molecular dynamics simulations. This combination of experiment and theory should lead to a better understanding of the connection between microscopic chain motion and macroscopic polymer properties. The specific systems whose chain dynamics will be investigated are: (i) polycarbonates with specifically fluorinated phenyl rings; (ii) high-Tg polycarbonate-polyester block copolymers; (iii) non-linear hyperbranched polycarbonates; and (iv) polycarbonates with main and side-chain cyclohexyl rings. %%% The polymers that will be characterized by solid-state NMR and molecular dynamics simulations in this proposal are of current interest to industry. A tough, cheap replacement for polycarbonate that has a lower birefringence to enable more information to be packed on compact disks is a commercial goal for a number of industries.. The ability to combine theory and experiment in fundamental work on problems that also are of great practical interest guarantees an efficient transfer to the American materials industry of the basic polymer science and technology developed at Washington University under NSF sponsorship. ***

[9729734] Schaefer本项目结合固态、魔角旋转、偶极重耦核磁共振实验和广义朗之万动力学模拟，对新一代工程聚合物的链式运动进行表征。这种聚合物基于聚碳酸酯类结构，具有增强的机械或光学性能。核磁共振用于测量作为分子动力学模拟约束的链间距离。这种实验与理论的结合将有助于更好地理解微观链运动与宏观聚合物性能之间的联系。将研究链动力学的具体体系有：(i)具有特定氟化苯基环的聚碳酸酯；（ii）高tg聚碳酸酯-聚酯嵌段共聚物；（iii）非线性超支化聚碳酸酯；（iv）具有主链和侧链环己基环的聚碳酸酯。在这个提议中，将用固态核磁共振和分子动力学模拟来表征的聚合物是目前工业感兴趣的。一个坚固，廉价的替代品聚碳酸酯具有较低的双折射，使更多的信息被封装在光盘是许多行业的商业目标。将理论和实验结合起来解决具有重大实际意义的基础问题的能力保证了华盛顿大学在国家科学基金资助下开发的基础聚合物科学和技术有效地转移到美国材料工业。＊＊＊