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：聚合物的一个独特特性是它们能够在冲击事件中吸收机械能，并将该能量转化为单个聚合物链的分子运动。 该项目的重点是研究能量吸收聚合物平台的基本材料特性，并开发一个工具箱来引入分子机制，以提高韧性、能量耗散以及纳米级自修复的潜力，从而延长材料的使用寿命。该平台基于称为“硫醇-烯网络热固性材料”的聚合物网络材料。它们可以通过化学反应制成，提供快速的反应时间和高度均匀的网络，如链环围栏，从而产生高能量吸收能力。萨文小组之前的工作已经证明了在网络中进行分子水平变化的能力，并将其转化为材料物理性质的宏观变化。 这些改变可以使用简单的化学以模块化的方式完成。 所得材料可应用于隔音、防碎涂层、个人防护装备（例如护齿套和多重冲击泡沫）和防弹保护。 科学发现的进步将融入学生的教育和培训中，整合化学、物理、生物化学和高分子科学等广泛学科。 小组成员将从基础和应用的角度全面了解聚合物的合成、表征、形态、散射和流变学等许多领域。 这种多学科方法不仅有利于教育，而且有利于培养全面发展的毕业生，他们对学术和工业环境中的各种雇主都有吸引力。还大力强调 K-5 基础科学推广的多样性和参与度。技术摘要：本研究的目的是研究基于硫醇-烯网络 (TEN) 热固性材料的能量吸收聚合物平台的基本材料特性。之前对 TEN 的研究表明，它能够通过化学进行分子水平的操作，并将其转化为宏观性能和功能的变化。这项研究的目标是利用 TEN 修饰的进展来合成新的单体，我们引入了增强韧性的机制，以及最终延长材料寿命的自我修复潜力。这将对板状材料（目标 1）和泡沫材料（目标 2）执行此操作。在拟议的研究中，我们将通过动态共价牺牲、机械化学连接以及光响应液晶偶氮苯取代基的结合来介绍这些能量耗散和韧性的分子级机制。构建网络修改工具箱将使我们能够发现有潜力通过扩展功能来改变能量吸收材料领域的材料。该提案中将开发的改良十材料平台是完全模块化的，可应用于个人防护设备、可固化涂层、防弹防护、牙科修复剂和聚合物复合材料等应用。成功完成拟议的研究将产生一个具有改进的冲击能量吸收特性的材料平台，以及对分子设计和操作如何转化为动力学和宏观功能的理解。该奖项反映了 NSF 的法定使命，并被认为是值得的通过使用基金会的智力优势和更广泛的影响审查标准进行评估来提供支持。