Building a Platform of Impact-Energy Absorbing Materials: How Molecular Manipulations Translate into Macroscopic Properties

构建冲击能量吸收材料平台：分子操纵如何转化为宏观特性

• 批准号: 1808204
• 负责人: Brent Sumerlin
• 金额: $ 33.9万
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1808204&HistoricalAwards=false
• 关键词: Building; Platform; Impact; Energy; Absorbing

NON-TECHNICAL SUMMARY:A unique property of polymers is their ability to absorb mechanical energy during impact events by transferring that energy into molecular motions of the individual polymer chains. This project is focused on studying the fundamental materials properties for a platform of energy-absorbing polymers and developing a toolbox to introduce molecular mechanisms to increase toughness, energy dissipation, and the potential for nanoscale self-healing that will increase the lifespan of the material. This platform is based on polymer network materials called "thiol-ene network thermosets". They can be made through chemistry that offers fast reaction times and highly homogeneous networks, like a chain-link fence, resulting in high energy absorption capacity. Previous work in the Savin group has demonstrated the ability to make molecular-level changes in the network and have this translate into macroscopic changes in the physical properties of the materials. These changes can be done in a modular way using facile chemistry. The resulting materials have applications in sound damping, shatterproof coatings, personal protective equipment (e.g., mouthguards and multi-impact foams), and ballistics protection. Advances in scientific discovery will be incorporated into the education and training of students, integrating a broad range of disciplines including chemistry, physics, biochemistry, and polymer science. Group members will gain a comprehensive understanding of polymers in many areas of synthesis, characterization, morphology, scattering and rheology, from both a fundamental and an applied standpoint. This multidisciplinary approach is beneficial not only for education, but also to produce well-rounded graduates who are attractive to a variety of employers in both academic and industrial settings. Diversity and involvement in K-5 elementary science outreach are also strongly emphasized. TECHNICAL SUMMARY:The objective of this research is to study the fundamental materials properties for a platform of energy absorbing polymers based on thiol-ene network (TEN) thermosets. Previous research on TENs has shown the ability to make molecular-level manipulations through chemistry and have this translate to changes in macroscopic performance and function. The goal of this research is to exploit advances in TEN modification to synthesize new monomers where we introduce mechanisms to increase toughness, as well as the potential for self-healing that will ultimately increase the life span of the material. This will be done for both slab (Aim 1) and foam (Aim 2) materials. In the proposed research, we will introduce these molecular-level mechanisms for energy dissipation and toughness through dynamic-covalent sacrificial, mechanochemical linkages, and incorporation of photo-responsive, liquid crystalline azobenzene substituents. Building a toolbox of network modifications will allow us to discover materials that have the potential to transform the field of energy-absorbing materials by expanding functionality. The modified TEN materials platform that will be developed in this proposal is completely modular and can be applied to applications such as personal protective equipment, curable coatings, ballistics protection, dental restoratives, and polymer composite materials. Successful completion of the proposed research will yield a platform of materials with improved impact-energy absorption properties, as well as an understanding of how molecular design and manipulation translates into dynamics and macroscopic function.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术摘要：聚合物的独特特性是它们通过将能量转移到单个聚合物链的分子运动中来吸收撞击事件期间的机械能的能力。 该项目的重点是研究一种吸收能量的聚合物平台的基本材料特性，并开发一种工具箱，以引入分子机制，以增加韧性，消散以及纳米级自我修复的潜力，从而增加材料的寿命。该平台基于称为“硫醇 - 烯网络热固体”的聚合物网络材料。它们可以通过化学反应，提供快速的反应时间和高度均匀的网络，例如链条围栏，从而产生高能量吸收能力。 Savin组的先前工作已经证明了在网络中进行分子级变化的能力，并将其转化为材料物理特性的宏观变化。 这些变化可以使用便捷的化学以模块化的方式进行。 所得的材料在声音阻尼，防碎涂料，个人防护设备（例如，枪手和多影响力泡沫）和弹道保护方面具有应用。 科学发现的进步将纳入学生的教育和培训中，融合了包括化学，物理，生物化学和聚合物科学在内的广泛学科。 小组成员将从基本和应用的角度均可在许多合成，表征，形态，散射和流变的领域中获得全面的理解。 这种多学科的方法不仅对教育也有益，而且还可以培养出全面的毕业生，这些毕业生在学术和工业环境中对各种雇主都有吸引力。还强烈强调了K-5基础科学外展的多样性和参与。技术摘要：这项研究的目的是研究基于硫醇 - 烯网络（十）热剂的能量吸收聚合物平台的基本材料特性。先前对TENS的研究表明，通过化学进行分子水平操作的能力，并将其转化为宏观性能和功能的变化。这项研究的目的是利用十项修饰的进步来综合新单体，在那里我们引入了提高韧性的机制，以及自我修复的潜力，最终将提高材料的寿命。这将用于平板（AIM 1）和泡沫（AIM 2）材料。在拟议的研究中，我们将通过动态的牺牲，机械化学链接以及掺入光响应性的液晶偶氮苯取代基，引入这些分子级机制，以耗散能量和韧性。构建网络修改工具箱将使我们能够发现有可能通过扩展功能来改变吸收能量材料领域的材料。该提案中将开发的修改后的十种材料平台是完全模块化的，可以应用于个人保护设备，可固化涂料，弹道保护，牙科修复和聚合物复合材料等应用。成功完成拟议的研究将产生具有改善影响能力吸收特性的材料平台，并了解分子设计和操纵如何转化为动态和宏观功能。该奖项反映了NSF的法定任务，并通过使用该基金会的知识分子优点和广泛的影响来评估NSF的法定任务。