GOALI: CAS: Targeted Design of Blocky Poly(Ether Ether Ketone) Copolymers for Enhanced Interfacial Interactions in Blends and Composites

非技术总结：目前对增强材料性能的需求通常遵循自下而上的方法，使用复杂的化学程序合成新的聚合物，这通常只是扩大了环境中大量持久塑料的范围。更可持续的方法是以新的方式使用现有材料。例如，聚醚醚酮（PEEK）的高成本及其固有的稳定性非常有利于使用结束后的回收和/或升级回收，而不是填埋。在这个项目中，通过对PEEK的现有原料进行简单的化学改性，可以实现在共混物中增容聚合物的广泛应用，以解决我们社会对经济和环境可持续性的关键需求。具体来说，将使用一种新的物理方法来创建块状共聚物，这种共聚物通过选择性地修改沿商用聚合物链的特定单元序列，已知对聚合物共混物有益。块状PEEK聚合物将针对PEEK与其他有价值的聚合物的新共混物，作为消除浪费和将PEEK升级为具有协同增强性能的新材料的手段。这些相同的聚合物也将用于促进PEEK和固体填料之间的牢固结合，形成具有增强机械性能的新复合材料。鉴于我们社会面临的巨大挑战，该项目将提供具有成本效益，环保，易于获得的材料替代品，以满足广泛的商业相关技术对先进材料的关键需求。这个项目的研究活动涉及学术和工业实验室之间的密切合作，其性质将向不同的研究人员和学生群体，包括代表性不足的群体，提供广泛的跨学科培训。技术概述嵌段共聚物作为共混增容剂和纤维浆料的广泛商业应用受到昂贵和严格的聚合方法的限制，这些方法需要以离散嵌段的形式控制共聚物的顺序。作为一种变革性的方法，pi们提出了一种简单的、物理的聚合物化学替代方案，通过非均相、半结晶、凝胶状态的聚合后官能化，来控制聚醚醚酮（PEEK）中块状微结构的产量。该项目的基本重点将放在突破这种新工艺所能达到的块化极限，扩展功能化化学的合成工具箱，以实现目标界面相互作用/反应，并了解块化功能化对高性能聚合物共混物和复合材料中相行为和界面相互作用的分子水平影响。这种学术-工业合作旨在解决基于peek的共混物和复合材料形成界面活性共聚物的巨大挑战，其增容效率可与传统的分段嵌段共聚物相媲美。本项目的总体基本目标是了解相容剂微观结构（块状与随机）对多相体系界面特性的作用。该项目的跨学科性质的研究活动，从纯化学、材料可回收性到大分子工程，将为渴望为我们的国家在确保一个更健康、更可持续的全球社会中发挥领导作用的不同社区的公民和研究人员提供大量的教育机会。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。

NON-TECHNICAL SUMMARY:The current demand for enhanced material properties has often followed a bottom-up approach to synthesize new polymers using complex chemical procedures that generally just expands that vast array of long-lasting plastics in the environment. A more sustainable approach is to use existing materials in new ways. For example, the high cost of poly(ether ether ketone) (PEEK) and its inherent stability strongly favor end-of-use recycling and/or upcycling as opposed to landfilling. In this project, the widely valued approach of compatibilizing polymers in blends to address the critical economic and environmental sustainability needs of our society will be accomplished by performing simple chemical modifications on existing feedstocks of PEEK. Specifically, a new physical approach will be used to create blocky copolymers that are known to be beneficial in polymer blends by selectively modifying specific sequences of units along the chains of commercially available polymers. The blocky PEEK polymers will be targeted toward new blends of PEEK with other valuable polymers as a means to eliminate waste and upcycle PEEK to new materials with synergistic enhancements in properties. These same polymers will also be used to facilitate strong bonds between PEEK and solid fillers in the formation of new composites with enhanced mechanical properties. With respect to the grand challenges facing our society, this project will provide cost-effective, environmentally friendly, readily available materials alternatives needed to meet critical demands for advanced materials in a wide range of commercially relevant technologies. The nature of research activities in this project, involving close collaboration between academic and industrial laboratories, will provide broadly interdisciplinary training to a diverse community of researchers and students, including underrepresented groups.TECHNICAL SUMMARYThe widespread commercial application of block copolymers as blend compatibilizers and fiber sizings is limited by the expensive and rigorous polymerization methods needed to control the sequence of comonomers in the form of discrete blocks. As a transformative approach, the PIs propose a facile, physical polymer chemistry alternative to yield controlled blocky microstructures in poly(ether ether ketone) (PEEK) via post-polymerization functionalizations in a heterogeneous, semi-crystalline, gel state. The fundamental focus of this project will be on pushing the limits of blockiness that is achievable with this new process, expanding the synthetic toolbox of functionalization chemistries for targeted interfacial interactions/reactions, and understanding the molecular-level impact of blocky functionalization on phase behavior and interfacial interactions in high-performance polymer blends and composites. This academic-industrial collaboration is poised to address the grand challenge of forming interfacially active copolymers for PEEK-based blends and composites, with compatibilization efficiencies rivaling that observed with conventional segmented block copolymers. The overall fundamental goal of this project is to understand the role of the compatibilizer microstructure (blocky vs. random) on interfacial properties in multiphase systems. The interdisciplinary nature of research activities in this project, ranging from pure chemistry, materials recyclability, to macromolecular engineering, will provide a plethora of educational opportunities to a diverse community of citizens and researchers eager to contribute to our nation’s leadership in ensuring a healthier, more sustainable global society.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.