Polymer Networks Containing Reversibly Associating Side-Groups

含有可逆缔合侧基的聚合物网络

• 批准号: 0906627
• 负责人: Mitchell Anthamatten
• 金额: $ 30万
• 依托单位: University of Rochester
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0906627&HistoricalAwards=false
• 关键词: Polymer; Networks; Containing; Reversibly; Associating

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).TECHNICAL SUMMARY: This research involves the design, synthesis, and study of network polymers containing highly selective, multiple hydrogen-bonding side-groups. The major research goal is to understand how reversible binding affects the material?s rate-of-strain and mass transport kinetics. Shape memory polymers (SMPs) will be developed that 1) are transparent to light at all processing temperatures, 2) exhibit amorphous or rubbery low-temperature states, and 3) enable precise tuning of shape recovery temperatures and rates. Preliminary studies have shown that lightly crosslinked elastomers containing reversibly associating side-groups exhibit shape-memory effects with a unique temperature-dependent shape-recovery. Planned research builds on these findings through the synthesis of well-defined elastomers involving uncrosslinked (linear) polymer precursors. Living free radical polymerization of poly(acrylates) will be performed to systematically vary architectural parameters including a) covalent crosslink density, b) associating side-group content, c) side-group spacer length, and d) the type and strength of H-bonding side-group. Synthesized polymers and networks will be studied in solution and in the melt to elucidate mechanistic details that influence shape memory responses. Research will pave the way to develop new features including two-stage shape responses, light and magnetic field triggered responses, and recyclable shape-memory materials. Research will also examine how reversible hydrogen-bonding affect mass transport. Diffusion of small molecules through synthesized networks will be studied using a custom-built permeation apparatus as well as multiphoton fluorescence recovery after photobleaching (MP-FRAP) techniques. The research plan provides a springboard for the PI to investigate biomedical devices including intraocular lenses, spinal disk prosthetics, and drug delivery platforms.NON-TECHNICAL SUMMARY: The principle investigator?s laboratory has recently developed novel shape-memory elastomers that use strong, reversible hydrogen-bonding groups to modify mechanical properties. The described study is to systematically vary the material architecture to fundamentally understand how reversible association affects time-scales of mechanical deformation and mass transport. The resulting knowledge will establish clear material design principles to foster new technologies including shape memory polymers, thermoplastic elastomers, and self-healing materials. Material responsiveness may also be exploited to engineer drug delivery devices and soft-tissue prosthetics designed for minimally invasive surgery. Educational aims are closely tied to research objectives. Graduate and undergraduate students will acquire research skills including polymer synthesis, rheology, transport studies, and thermal mechanical analysis. The research described is synergistic with a new course, ?Engineering of Soft Matter?, which introduces students to this emerging field. In addition, the PI will further develop the education outreach program "Green Engineering" to provide professional development opportunities to high school teachers. This program strengthens connections between secondary education teachers and the technical workforce by offering hands-on teaching workshops. There, high school teachers learn and discuss emerging ?green? technologies including energy conservation, photovoltaics, and fuel cells.

该奖项由2009年美国复苏和再投资法案(公法111-5)资助。技术摘要：这项研究涉及含有高度选择性的多个氢键侧基的网络聚合物的设计、合成和研究。主要的研究目标是了解可逆结合如何影响材料的S应变率和质量传输动力学。形状记忆聚合物(SMPS)将被开发为1)在所有加工温度下对光透明，2)呈现无定形或橡胶状低温状态，以及3)能够精确调节形状恢复温度和速率。初步研究表明，含有可逆缔合侧基的轻交联弹性体表现出形状记忆效应，具有独特的温度依赖性形状恢复。计划中的研究建立在这些发现的基础上，通过合成涉及非交联性(线性)聚合物前体的明确定义的弹性体。聚丙烯酸酯的活性自由基聚合将系统地改变结构参数，包括a)共价交联密度，b)侧基含量，c)侧基间隔基长度，d)氢键侧基的类型和强度。合成的聚合物和网络将在溶液和熔体中进行研究，以阐明影响形状记忆响应的机理细节。研究将为开发包括两阶段形状响应、光和磁场触发响应以及可回收形状记忆材料在内的新功能铺平道路。研究还将研究可逆氢键如何影响质量传输。小分子在合成网络中的扩散将使用定制的渗透设备以及光漂白后多光子荧光恢复(MP-FRAP)技术进行研究。该研究计划为PI研究包括人工晶状体、脊柱假体和药物输送平台在内的生物医学设备提供了一个跳板。非技术概述：首席研究员S实验室最近开发出新型形状记忆弹性体，它使用强大的可逆氢键基团来改变机械性能。所描述的研究是为了系统地改变材料的结构，以从根本上了解可逆缔合如何影响机械变形和质量传输的时间尺度。由此产生的知识将建立明确的材料设计原则，以促进新技术的发展，包括形状记忆聚合物、热塑性弹性体和自我修复材料。材料的响应性也可能被用来设计药物输送装置和设计用于微创手术的软组织假体。教育目标与研究目标密切相关。研究生和本科生将获得研究技能，包括聚合物合成、流变学、运输学和热机械分析。所描述的研究是与一门新课程--软物质工程学--协同进行的，该课程向学生介绍了这一新兴领域。此外，该协会将进一步发展教育外展计划“绿色工程”，为高中教师提供专业发展机会。该计划通过提供实践教学研讨会来加强中等教育教师和技术劳动力之间的联系。在那里，高中老师学习和讨论新兴？绿色？包括节能、光伏和燃料电池在内的技术。