Statistical Mechanics of Polymer Systems

9530403自由理论研究将继续发展理论计算聚合物熔体，共混物，嵌段共聚物，玻璃和液晶的热力学性质。 这种理论方法的一个主要和新颖的特点涉及单体分子结构，局部相关性和可压缩性的联合治疗。 首席研究员将继续这项工作，通过扩展他的晶格集团理论，包括半柔性，以描述聚合物玻璃和液晶。 拟议的研究的另一个方面将涉及短链支化（和半柔性）对聚合物共混物（特别关注聚烯烃共混物）的相容性的影响的持续研究，如果时间允许，对它们的界面性能。 其他有待研究的现象包括聚合物共混物的溶解性和玻璃化转变温度的压力依赖性。 精确描述聚合物共混物和聚合物液晶与模型包含复杂的单体结构将需要包括贡献从远程相关性，贡献，只能评估与援助的复杂的基于计算机的组合算法，将被设计和应用到这个项目。 这个理论研究包括分析和计算两个部分。 该研究将确定聚合物及其混合物的各种性质，使用由主要研究者开发的形式主义。 为了模拟更现实的情况，将对这种形式主义进行修改。 ***

9530403 Freed Theoretical research will continue on developing theories for calculating the thermodynamic properties of polymer melts, blends, block copolymers, glasses and liquid crystals. A main and novel feature of this theoretical approach involves the combined treatment of monomer molecular structures, local correlations, and compressibility. The principal investigator will continue this work by extending his lattice cluster theory to include semiflexibility in order to describe polymer glasses and liquid crystals. Another aspect of the proposed research will involve continued studies of the influence of short chain branching (and semiflexibility) on the miscibility of polymer blends (with special focus on polyolefin blends) and, if time permits, on their interfacial properties. Other phenomena to be studied include the pressure dependence of polymer blend miscibility and glass transition temperatures. The accurate description of polymer blends and of polymer liquid crystals with models containing complex monomer structures will require the inclusion of contributions from long range correlations, contributions that only can be evaluated with the aid of sophisticated computer-based combinatorial algorithms which will be devised and applied to this project. %%% This theoretical research involves both analytical and computational components. The research will determine a variety of properties of polymers and their mixtures using a formalism developed by the principal investigator. Modifications to this formalism will be made in order to model more realistic situations. ***