Sustainable Triblock Copolymers with Supramolecular Interactions for Improved Performance

你们的社会依赖石油原料生产聚合物的缺点是原料供应有限，产生有害的环境排放和塑料废物，以及原料价格和可用性的不可预测性。尽管许多先前的研究已经开发了从各种资源（如植物糖、植物油、植物萜烯、二氧化碳、多糖、松香和微生物聚酯）中获得可持续材料的途径，但它们在社会上的广泛应用仍然存在挑战。一个重要的挑战是，新聚合物必须满足现有材料的性能和性能预期才能被采用。然而，从可持续来源开发的新聚合物很少是传统聚合物的简单替代品。该项目面临的持续挑战是，许多可持续聚合物的特性会对其性能产生重大不利影响，并限制其使用。本项目所积累的知识将为克服这些限制提供一条途径，使其有可能在应用中得到广泛采用。该项目还将利用外展计划培养学生和公众对聚合物在社会中的重要作用及其对环境的影响的认识。休斯敦大学的材料日项目提供了动手实验室体验的机会，将扩展可持续聚合物的新模块。本科生和研究生将通过参与研究项目获得宝贵的经验。最后，可持续聚合物的演示将在休斯敦能源日举行。从可持续来源开发具有优异物理性能和更大功能的先进聚合物材料是减少聚合物对环境影响的一个根本性的重要挑战。植物油及其脂肪酸是聚合物的方便来源，因为它们的广泛可用性，易于功能化，并且没有毒性。组成植物油的脂肪酸的长烷基链对聚合物的性能有很大的影响，这可以通过植物油原料的选择来调节。不幸的是，具有庞大成分的聚合物，如脂肪酸衍生聚合物的长烷基侧链，由于缺乏缠结，通常表现出较差的机械性能。在这个项目中，超分子相互作用将被纳入植物油衍生聚合物中，作为改善其机械行为的途径。这项工作的中心假设是，在可持续三嵌段共聚物中加入超分子相互作用将导致一类具有增强物理性能的新型可持续材料。长链聚（甲基）丙烯酸酯将被官能团修饰以促进氢键和离子相互作用。这些材料将作为ABA三嵌段共聚物的中间嵌段。材料的有效交联密度和粘弹性性能将被量化。最后，建立了超分子相互作用的强度、动力学和类型与聚合物物理性质之间的关系。这些材料将作为热塑性弹性体、形状记忆材料和自愈材料进行探索。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

PART 1: NON-TECHNICAL SUMMARYOur society's dependence on petroleum feedstocks for polymers has drawbacks of a limited raw material supply, generation of harmful environmental emissions and plastic waste, and unpredictability in feedstock prices and availability. Though many prior studies have developed routes to sustainable materials from a variety of resources such as plant sugars, plant oils, plant terpenes, carbon dioxide, polysaccharides, rosins, and microbial polyesters, challenges still persist in their broad implementation in society. One significant challenge is that new polymers must meet the performance and property expectations of existing materials in order to be adopted. However, new polymers developed from sustainable sources are rarely simple drop-in replacements for conventional polymers. The persistent challenge that this project addresses is that many sustainable polymers have features which significantly and adversely impact their properties and limit their use. The knowledge developed in this project will provide a route to overcoming these limitations, enabling the potential of widespread adoption in applications. This project will also use outreach programs to cultivate knowledge among students and the general public on the important role of polymers in society and their environmental impacts. The Materials Day at UH program, providing opportunities for hands-on laboratory experiences, will be expanded with new modules in sustainable polymers. Undergraduate and graduate students will gain valuable experiences through involvement in the research projects. Finally, demonstrations on sustainable polymers will be developed for the Houston Energy Day festival. PART 2: TECHNICAL SUMMARYDeveloping advanced polymeric materials from sustainable sources with superior physical properties and greater function is a fundamentally important challenge in reducing the environmental impact of polymers. Vegetable oils and their fatty acids are convenient sources for polymers due to their wide availability, ease of functionalization, and lack of toxicity. The long alkyl chains of the fatty acids comprising vegetable oils have a large impact on the resulting polymer properties, which are tunable through choice of vegetable oil feedstock. Unfortunately, polymers with bulky constituents, such as the long alkyl side-chains of fatty acid-derived polymers, typically exhibit poor mechanical performance due to lack of entanglements. In this project, supramolecular interactions will be incorporated into the vegetable oil-derived polymers as a route to improve their mechanical behavior. The central hypothesis of this work is that the incorporation of supramolecular interactions in sustainable triblock copolymers will lead to a new class of sustainable materials with enhanced physical properties. Long-chain poly(meth)acrylates will be modified with functional groups to promote hydrogen bonding and ionic interactions. These materials will be incorporated as the midblock of ABA triblock copolymers. The effective crosslink density and viscoelastic properties of the materials will be quantified. Finally, relationships between the strength, dynamics, and type of supramolecular interactions and the polymer physical properties will be established. These materials will be explored as thermoplastic elastomers, shape memory materials, and self-healing materials. .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.