Dynamics of Polymer Mixtures: Intermolecular Coupling and Crystallizability

聚合物混合物的动力学：分子间偶联和结晶性

• 批准号: 0605627
• 负责人: James Runt
• 金额: $ 33万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-06-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0605627&HistoricalAwards=false
• 关键词: Dynamics; Polymer; Mixtures; Intermolecular; Coupling

TECHNICAL SUMMARY:Previous research on segmental and local dynamics of associating polymer blends and solutions, carried out with NSF-DMR support, focused on the roles of composition, intermolecular hydrogen bonding strength, and intrinsic component mobility differences. This research was conducted principally using dielectric spectroscopy, taking advantage of its ultra-broad frequency range and high sensitivity. This earlier work prompted a number of fundamental questions that will be answered through the proposed research. For example, what is the role of strong intermolecular coupling on the segmental dynamics when self-association of the component polymers is minimized? At what length scale does the segmental dynamics crossover from homogeneous to heterogeneous character? The second part of the proposed work seeks to establish the origin of a novel fast process observed in the dielectric spectra of miscible blends. The principle questions to be addressed in this part of the research include: Does component polymer crystallizability play an important role in determining heterogeneity of miscible blends between weakly associating polymers? Are such blends capable of capturing nascent crystal formation and hence serving as model systems for the investigation of crystal nucleation, the most significant unresolved problem in the field of polymer crystallization?NON-TECHNICAL SUMMARY:Mixing of unlike polymers is known to be an efficient and cost effective means of creating novel alloys with enhanced properties, and has important industrial and fundamental significance. Mixing is facilitated by the formation of strong intermolecular bonding between the two polymers, but little is known about the precise role such strong bonding plays in modifying molecular, and consequently macroscopic, properties. The first part of the proposed research focuses on the investigation of intermolecular bonding strength on the mobility of the component polymers in the mixture. The second portion seeks to understand the influence of component polymer ordering (crystallization) on mixture mobility. The latter systems will also serve as models for the investigation of crystal nucleation, the most significant unresolved problem in the field of polymer crystallization.This program broadly impacts the field of materials research in several ways. The proposed research will create learning opportunities for graduate and undergraduate students, including building teamwork skills from frequent group and inter-group meetings where ideas are exchanged. Each participant in the program will be engaged in the extensive and vital outreach program of the Penn State Center for Nanoscale Science, an NSF Materials Research Science and Engineering Center. Finally, collaborative studies will be undertaken with the research group of Prof. George Floudas (U. Ioannina, Greece), and an exchange of student researchers with his group is anticipated over the course of this program.

技术综述：以前在NSF-DMR支持下开展的缔合聚合物共混物和溶液的链段和局部动力学研究，侧重于组成、分子间氢键强度和固有组分迁移率差异的作用。本研究主要利用介电光谱的超宽频率范围和高灵敏度进行研究。这项早期的工作引发了一些基本问题，这些问题将通过拟议的研究得到解答。例如，当组分聚合物的自缔合作用被最小化时，强分子间耦合对链段动力学的作用是什么？从同质特征到异质特征的分段动力学在多长的尺度上交叉？这项工作的第二部分试图确定在可混溶共混物的介电谱中观察到的一种新的快速过程的起源。在这部分研究中要解决的主要问题包括：组成聚合物的结晶性在决定弱缔合聚合物之间可混溶混合物的异质性方面是否起着重要作用？这种共混物是否能够捕获新晶体的形成，从而作为研究结晶成核的模型系统，晶体成核是聚合物结晶领域最重要的悬而未决的问题？非技术摘要：混合不同的聚合物被认为是创造具有增强性能的新型合金的一种有效和经济有效的方法，具有重要的工业和基础意义。两种聚合物之间形成了强大的分子间键，从而促进了混合，但人们对这种强键在修饰分子从而改变宏观性质方面所起的确切作用知之甚少。研究的第一部分集中于分子间结合强度对混合物中各组分聚合物流动性的影响。第二部分旨在了解组成聚合物有序化(结晶)对混合物流动性的影响。后一个系统还将作为研究结晶成核的模型，结晶成核是聚合物结晶领域最重要的悬而未决的问题。该计划在几个方面广泛地影响了材料研究领域。这项拟议的研究将为研究生和本科生创造学习机会，包括通过频繁的小组会议和小组间会议培养团队合作技能，在那里交换想法。该计划的每个参与者都将参与宾夕法尼亚州立纳米科学中心的广泛而重要的扩展计划，该中心是美国国家科学基金会的材料研究科学和工程中心。最后，将与乔治·弗洛达斯教授的研究小组(U·Ioannina，希腊)进行合作研究，并预计在该项目的过程中与他的小组交换学生研究人员。