Understanding rapid pseudo-solid state step-growth polymerization in micro-layers leading to ultra-high molecular weight polymers with unusual molecular structures

了解微层中的快速伪固态逐步增长聚合，从而产生具有不寻常分子结构的超高分子量聚合物

• 批准号: 1033071
• 负责人: Kyu Yong Choi
• 金额: $ 33.25万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1033071&HistoricalAwards=false
• 关键词: Understanding; rapid; pseudo; solid; state

1033071ChoiThis research will investigate the pseudo-solid state step-growth polymerization in the confined reaction space of an amorphous polymer micro-layer where high to ultra-high molecular weight (MW) polymers are rapidly produced. Pseudo-solid state polymerization (p-SSP) has the ability to produce ultra-high MW polymers in short reaction times. The extraordinary high MWs and the exceptional properties of the final polymer can only be compared with condensation polymers produced via ring opening polymerization, but p-SSP is more economically feasible and environmentally friendly.This polymerization technique consists of formulating a low MW amorphous polymer precursor with catalyst into a confined reaction space of a polymer micro-layer, and carrying out the polymerization at reduced pressures and at temperatures close to but below the polymer melting point. Preliminary experimental results indicate that the reaction proceeds more than 20 times faster than conventional solid state polymerizations in semi-crystalline particles, and polymer MWs and polydispersities notably exceed the theoretical limits of the classical step-growth polymerization theory. At moderate reaction times, insoluble/infusible structures coexist with soluble structures, and the final polymer exhibits excellent optical clarity. The presence of branched structures has been confirmed by 13C-NMR and 1H-NMR, and the rheological characterization of the polymer. The relatively high mobility of polymer chains in the amorphous state, the efficient removal of polycondensation byproduct from the micron-sized reaction space, the radical-induced branching reactions via thermal decomposition of the residual casting solvent or via scission reactions, Fries rearrangement, interchange reactions, and high reactivities are hypothesized to be mainly responsible for the fast and unusual increase of the polymer MWs and the formation of insoluble polymer. Three model systems have been investigated: bisphenol-A polycarbonate, poly(L-lactic acid), and a copolymer of polycarbonate and poly(dimethylsiloxane). It is expected that the technique can be applied to many other condensation systems, suggesting that p-SSP can have a broad impact on step-growth polymerization technology. Through experimental and theoretical studies, this project will develop fundamental understandings of the chemical and physical phenomena that govern the p-SSPs process.The Intellectual Merit: The goal is to develop new quantitative understandings of the chemical and physical phenomena that drive the kinetics of p-SSP to unusual reaction behaviors through experimentation and theoretical modeling. P-SSP is different from melt and conventional solid-state polymerizations, and its kinetics deviates from the traditional approaches. Integration of comprehensive experimentation and mathematical modeling will provide a systematic way to produce tailor-made condensation polymers for a variety of special applications where high or ultra-high MWs, solvent resistance, and thermal resistance are required.The Broader Impacts of the Proposed Study: P-SSP is a method to produce ultra-high MW condensation polymers in short reaction times. This research will provide fundamental data and knowledge for the development of an advanced polymerization process technology, especially for large-scale mass production, as well as new polymer properties. For instance, the synthesis of insoluble and infusible structures for traditionally soluble polymers can inspire a variety of novel applications. The research results are expected to be applicable to many other condensation polymerizations. The results of the research will be presented at relevant scientific and engineering fields. Undergraduate students at all levels, regardless of ethnic background and gender, will be strongly encouraged to participate in the proposed project as semester research or summer internship programs. Academically talented high school students will also be invited to a summer research experience program through University of Maryland's Women In Engineering (WIE) program. The participating students at different levels will be encouraged to develop innovative applications and test the ideas as the research progresses.

1033071 Choi本研究将研究在无定形聚合物微层的受限反应空间中的伪固态逐步生长聚合，其中快速产生高至超高分子量（MW）聚合物。拟固相聚合（p-SSP）具有在短反应时间内制备超高分子量聚合物的能力。最终聚合物的超高分子量和优异的性能只能与通过开环聚合制备的缩聚物相比，但p-SSP更经济可行且环境友好。该聚合技术包括将具有催化剂的低分子量无定形聚合物前体配制到聚合物微层的受限反应空间中，并在减压和接近但低于聚合物熔点的温度下进行聚合。初步的实验结果表明，反应进行超过20倍，比传统的固态聚合在半结晶颗粒，聚合物分子量和多分散性显着超过经典的逐步增长聚合理论的理论极限。在适度的反应时间下，不溶性/不溶性结构与可溶性结构共存，并且最终聚合物表现出优异的光学透明度。通过~（13）C-NMR和~ 1H-NMR以及聚合物的流变学表征证实了支化结构的存在。聚合物链在无定形状态下的相对高的移动性，从微米级反应空间中有效除去缩聚副产物，通过残余浇铸溶剂的热分解或通过断裂反应的自由基诱导的支化反应，弗里斯重排，交换反应，高反应活性是聚合物分子量快速增加和不溶性聚合物形成的主要原因。三个模型系统进行了研究：双酚A聚碳酸酯，聚（L-乳酸），和聚碳酸酯和聚（二甲基硅氧烷）的共聚物。预计该技术可以应用于许多其他缩合体系，这表明p-SSP可以对逐步增长聚合技术产生广泛的影响。本项目通过实验和理论研究，对p-SSP反应过程中的化学和物理现象有了基本的认识。智力成果：通过实验和理论模拟，对p-SSP反应动力学中的异常反应行为的化学和物理现象有了新的定量认识。P-SSP不同于熔融聚合和常规固相聚合，其动力学偏离传统方法。综合实验和数学建模的集成将提供一种系统的方法，为各种特殊应用生产量身定制的缩合聚合物，这些应用需要高或超高分子量、耐溶剂性和耐热性。拟议研究的更广泛影响：P-SSP是一种在短反应时间内生产超高分子量缩合聚合物的方法。该研究将为开发先进的聚合工艺技术，特别是大规模生产以及新的聚合物性能提供基础数据和知识。例如，传统可溶性聚合物的不溶性和不溶性结构的合成可以激发各种新的应用。研究结果对其它缩聚反应具有一定的指导意义。研究结果将在相关科学和工程领域发表。各级本科生，无论种族背景和性别，将被强烈鼓励参加拟议的项目作为学期研究或暑期实习计划。学术上有才华的高中生也将被邀请参加马里兰州大学的妇女工程（WIE）项目的夏季研究体验项目。我们鼓励不同层次的参与学生在研究过程中开发创新的应用程序，并测试他们的想法。