GOALI: Thermodynamics of Fluid-Solid Equilibria in Solutions of Crystallizable Aromatic-Ring Containing Polymers

可结晶聚合物可以通过冷却或压缩从溶液中以结构固相的形式析出。所提出的研究的总体目标是了解可结晶芳环聚合物在可压缩流体流中的固相行为，例如近临界和超临界流体溶液。这种理解不仅需要开发新的聚合物材料，而且需要开发新的和改进现有的制造工艺；使其能耗更低，更环保。例如，需要这样的理解来实现理想的相变，并避免导致管道、反应器和分离器中结垢现象的不良相变。提出的方法是：(1)在高压实验中表征含芳烃模型聚合物，如聚（乙烯-苯乙烯）和聚（1,3-环hezadine）衍生物的流固转变；(2)建立一个基于状态方程的热力学模型，可以解释和预测可结晶的固相转变。该方法的基础是一系列初步但有希望的实验结果和最新版本的状态方程（称为SAFT（统计关联流体理论））的计算结果。SAFT可以明确地解释微观结构和芳香性对聚合物和共聚物热力学性质的影响。这是以前从未做过的，将影响我们表征非常大的结构分子的方式。具体来说，这个项目中产生的知识将为未来更多的预测热力学模型和其他聚合物结构的研究提供种子，例如，具有不同分支长度和形状的结构（例如接枝聚合物和星形聚合物），增加骨干刚度的程度（一直到液晶聚合物），以及不同程度的分子间和分子内结合。这是因为在主支和侧支中具有芳香环的模型聚合物可以成为许多更复杂的大分子和超分子结构的基本构建块，这将是未来研究的目标。除了播种未来的研究，该项目将对现有和未来的聚合物技术产生直接和长期的影响。例如，SAFT模型将允许预测在实际的商业聚烯烃工艺中导致实际热交换器和反应器系统结垢的不良相变，例如现有的溶液聚（乙烯-co-苯乙烯）工艺和未来的聚苯乙烯工艺。

ABSTRACTCTS-9908610Maciej RadoszCrystallallizable polymers can precipitate from solution in the form of a structure solid phase by cooling or compression. The overall goal of the proposed research is to understand the solid-phase behavior of crystallizable aromatic-ring containing polymers in compressible-fluid streams, such as near critical- and supercritical-fluid solutions. Such understanding is needed not only to develop new polymeric materials, but also to develop new and improve existing manufacturing processes; to make then less energy intensive and more environmentally acceptable. For example, such understanding is needed to accomplish desirable phase transitions and to avoid undesirable phase transitions that cause fouling phenomena in pipelines, reactors and separators.The proposed approach is to (1) characterize aromatic-containing model polymers, such as poly(ethylene-co-styrene) and poly (1,3-cyclohezadine) derivatives, upon fluid-solid transition in high-pressure experiments, and (2) develop an equation-of-state-based thermodynamic model that can account for and predict the crystallizable solid-phase transitions. The basis for this approach is a series of preliminary but promising experimental results and computational results with recent versions of an equation of state referred to as SAFT (statistical associating fluid theory). SAFT can explicitly account for the effects of microstructure and aromaticity on the thermodynamic properties of polymers and copolymers. This has never been done before and will impact the way we characterize very large, structured molecules.Specifically, the knowledge generated in this project will seed future research on more predictive thermodynamic models and on the other polymer structures, for example, structures with different branch lengths, shapes (e. g. graft polymers and stars), increasing degree of the backbone rigidity (all the way to the liquid-crystalline polymers), and varying degree of inter- and intra-molecular association. This is because the proposed model polymers with aromatic rings in the backbone and side branches can be the basic building block for numerous more complicated macromolecular and supremolecular structures, which will be the target of future research.In addition to seeding future research, this project will have an immediate and long-term impact on the existing and future polymer technologies. For example, the SAFT model will allow for predicting the undesirable phase transition that lead to fouling of real heat-exchanger and reactor systems in real commercial polyolefin processes, such as the existing solution poly(ethylene-co-styrene) process and future polyphenylene processes.