Architectural Effects in the Phase Formation and Miscibility of SCLCPs Prepared by ATRP

ATRP 制备的 SCLCP 的相形成和混溶性的结构效应

• 批准号: 0322338
• 负责人: Coleen Pugh
• 金额: $ 34.5万
• 依托单位: University of Akron
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-15 至 2010-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0322338&HistoricalAwards=false
• 关键词: Architectural; Effects; Phase; Formation; Miscibility

In contrast to polymers based on conventional, non-mesogenic monomers, the effect of architecture on the properties of side-chain liquid crystalline polymers (SCLCPs) has barely been investigated. The synthesis of cyclic and branched SCPCPs is proposed in order to determine if high degrees of branching hinders the ability of the polymer to form a liquid crystalline phase, and in order to investigate whether or not the presence of a long mesogenic side chain in every repeat unit influences any of their solution and solid-state properties, such that the SCLCPs might appear to have greater branching than their nominal values. In particular, an ideal architecture is sought for generating SCLCPs with exceptionally fluid mesophases, such that either new applications can be identified or in order to compete with LMMLCs for applications that would benefit from the structural integrity of a polymer. These different architectures are also needed to investigate the source of the broad phase transitions often exhibited by SCLCPs synthesized by non-living polymerizations. New chemistry is proposed to synthesize the first cyclic polyacrylates and the first hyperbranched polyacrylates that are chemically analogous to linear polyacrylates; the hyperbranched polymers will contain an ester group attached to every other carbon atom along the polymer backbone, with a non-initiator-containing alkylester attached as a free side chain. All of the proposed architectures are new to the field of SCLCPs. The solution behavior of the polymers will be investigated by light scattering measurements and GPC as a function of molecular weight. The thermotropic behavior of the homopolymers will be determined as a function of molecular weight and extent of branching by DSC, polarized optical microscopy and possibly X-ray diffraction. Polarized optical microscopy will also be used to qualitatively determine how the extent of branching affects the polymers' dynamics, which will be correlated with the 13C-NMR T1C spin-lattice relaxation times of specific carbons within the mesogen, spacer, branch points and/or polymer backbone of each architecture. The spatial distribution of the components of the architectural blends will be characterized by magnetic resonance imaging.The proposed research is a multidisciplinary project that will train graduate students and postdoctoral researchers, including at least two women, in organic, polymer and physical chemistry. Undergraduate students may contribute through an REU summer supplement during summer months, with mentoring by the graduate students. All participants will present their work routinely at group meetings and ACS and Gordon conferences. Students and postdoctoral researchers will learn how to use Schlenk line synthetic techniques, and how to use NMR, GPC, DSC, polarized optical microscopy and light scattering in order to characterize their polymers, precursors and blends. Those students working on the chain transfer study will also learn how to use a high vacuum line for their kinetic measurements. This work may also contribute to improving the infrastructure of the University of Akron through the acquisition of an NMR imaging instrument if the university instrument proposal is successful.

与基于常规非介晶单体的聚合物相比，侧链液晶聚合物（SCLCP）的结构对性能的影响几乎没有研究。 提出了环状和支链SCPCP的合成，以确定高的支化度是否阻碍聚合物形成液晶相的能力，并且为了研究在每个重复单元中长的介晶侧链的存在是否影响它们的溶液和固态性质中的任何一个，使得SCLCP可能看起来具有比它们的标称值更大的支化。 特别是，寻求一种理想的结构，用于产生具有异常流体中间相的SCLCP，使得可以确定新的应用，或者为了与LMMLC竞争将受益于聚合物的结构完整性的应用。 这些不同的架构也需要调查来源的广泛的相变往往表现出的SCLCP合成的非活性聚合。 提出了新的化学方法来合成第一环状聚丙烯酸酯和第一超支化聚丙烯酸酯，它们在化学上类似于线性聚丙烯酸酯;超支化聚合物将含有沿着聚合物主链沿着每隔一个碳原子连接的酯基，其中不含引发剂的烷基酯作为游离侧链连接。 所有提出的架构都是SCLCP领域的新架构。 将通过光散射测量和GPC作为分子量的函数来研究聚合物的溶液行为。 均聚物的热致行为将通过DSC、偏光显微镜和可能的X射线衍射作为分子量和支化程度的函数来确定。 偏振光学显微镜也将用于定性地确定支化程度如何影响聚合物的动力学，其将与每种结构的介晶、间隔基、分支点和/或聚合物主链内的特定碳的13 C-NMR T1 C自旋-晶格弛豫时间相关。 将通过磁共振成像来表征建筑混合物组成部分的空间分布。拟议的研究是一个多学科项目，将在有机、聚合物和物理化学方面培训研究生和博士后研究人员，其中至少包括两名女性。 本科生可以在夏季通过REU夏季补充作出贡献，由研究生指导。 所有参与者将在小组会议和ACS和戈登会议上定期介绍他们的工作。 学生和博士后研究人员将学习如何使用Schlenk线合成技术，以及如何使用NMR，GPC，DSC，偏振光显微镜和光散射来表征其聚合物，前体和共混物。 从事链转移研究的学生还将学习如何使用高真空线进行动力学测量。 这项工作也可能有助于改善阿克伦大学的基础设施，通过购买核磁共振成像仪器，如果大学仪器的建议是成功的。