CAREER:Reaction Dynamics of Polymerization and a Computer- Enhanced Dialectic in the Physical Chemistry Curriculum

职业：物理化学课程中的聚合反应动力学和计算机增强辩证法

• 批准号: 9703372
• 负责人: Rigoberto Hernandez
• 金额: $ 32.04万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-07-01 至 2002-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9703372&HistoricalAwards=false
• 关键词: CAREER; Reaction; Dynamics; Polymerization; Computer

The Theoretical and Computational Chemistry program is supporting Professor Rigoberto Hernandez at the Georgia Institute of Technology as part of the CAREER program for young scientists. The objective of this research is to characterize the time-dependent behavior of the polymerization process. A bond percolation model on a novel lattice has been combined with an Ising-like Polymer Growth Hamiltonian (PGH) to provide non-uniform and correlated bond formation/breaking probabilities. It includes the pertinent reaction dynamics, but is simple enough to accommodate the Monte Carlo treatment of high (long-length) polymers. A new stochastic Hamiltonian has been built around the potential of mean force for the effective polymer `contour` length. The change of the macroscopic properties of the polymer as its length increases is included through an effective friction which explicitly depends on this length. Further study of the dynamics of this Hamiltonian, as well as its connection to the polymer-growth lattice Hamiltonian, should provide increased understanding of the connection between the monomer properties and reaction conditions, and of the resulting material properties of the polymer as a function of time. Hard plastics, chewing gum, glues, proteins and coatings are but a few examples of the diverse range of polymeric materials which have driven the polymer industry. Surprisingly, these materials are often obtained from the same base monomers, varying only reaction conditions and relative composition. What existing theories often leave out in their characterization of the final product is an understanding of the reaction dynamics when viscous effects affect the reaction process. This is important in thermoset polymers used in the encapsulation of microchips; the polymerization ends not because the reactants have been depleted, but because of diffusional quenching due to the dramatic change in viscosity as a function of the extent of reaction. The goal in this research is to understand the competition between the reactivity of the polymer and changes in the material's viscosity as a function of temperature and reaction profile. The educational component of this proposal comprises the development of a new physical chemistry course and a companion web-based textbook, both of which emphasize the connection between theoretical understanding and physical intuition. The course will also use various electronic forms of communication. It is hoped that this computer-enhanced dialectic (CED) will provide ample opportunity for the student to learn not only how to answer questions, but also how to ask the right ones.

理论和计算化学计划支持 格鲁吉亚理工学院的Rigoberto埃尔南德斯教授， 这是青年科学家职业计划的一部分。 的目的 研究的目的是表征 聚合过程 一种新的晶格上的键渗流模型， 与类伊辛聚合物生长哈密顿量（PGH）相结合， 提供不均匀和相关的键形成/断裂概率。 它包括相关的反应动力学，但足够简单， 适应高（长长度）聚合物的蒙特卡罗处理。 一 围绕平均势建立了一个新的随机哈密顿量 有效聚合物“轮廓”长度的力。 的变化 包括聚合物的宏观性质，因为它的长度增加 通过明显取决于该长度的有效摩擦。 进一步研究这个哈密顿量的动力学，以及它的 与聚合物生长晶格哈密顿量的连接，应该提供 增加对单体性质之间联系的理解 和反应条件，以及所得到的材料的性质， 作为时间的函数。 硬塑料、口香糖、胶水、蛋白质和涂料只是其中的几种 各种聚合物材料的例子 聚合物工业。 令人惊讶的是，这些材料往往是获得 由相同的基础单体，仅改变反应条件， 相对组成。 现有的理论经常遗漏了什么， 最终产物的表征是对反应的理解 当粘性效应影响反应过程时的动力学。 这是 在用于微芯片封装的热固性聚合物中很重要; 聚合反应的结束并不是因为反应物已经耗尽，而是 由于粘度的急剧变化引起的扩散淬火 作为反应程度的函数。 这项研究的目的是 为了理解聚合物的反应性与 材料粘度随温度的变化， 反应曲线 这项建议的教育部分包括 物理化学新课程及配套教材的开发 基于网络的教科书，两者都强调了 理论理解和物理直觉。 该课程还将 使用各种电子通讯方式。 希望这一 计算机增强辩证法（CED）将为 学生不仅要学会如何回答问题，还要学会如何提问 正确的选择