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

非技术摘要：当前对增强材料性能的需求通常遵循自下而上的方法，使用复杂的化学过程合成新聚合物，这通常只会扩大环境中大量持久的塑料。一种更可持续的方法是以新的方式利用现有材料。例如，聚醚醚酮(PEEK)的高成本和其固有的稳定性强烈有利于末端回收和/或升级循环，而不是垃圾填埋。在该项目中，通过对PEEK的现有原料进行简单的化学修饰，将实现广受重视的增容共混聚合物的方法，以满足我们社会的关键经济和环境可持续发展需求。具体地说，一种新的物理方法将被用来产生已知在聚合物共混物中有益的嵌段共聚物，方法是选择性地修改商业可获得的聚合物链上的特定单元序列。块状PEEK聚合物将用于PEEK与其他有价值的聚合物的新混合物，作为一种消除浪费的手段，并通过协同增强性能来提升PEEK对新材料的认识。这些聚合物还将用于促进PEEK和固体填料之间的牢固结合，以形成具有增强机械性能的新复合材料。对于我们社会面临的重大挑战，该项目将提供成本效益高、环境友好、容易获得的材料替代品，以满足各种商业相关技术对先进材料的关键需求。该项目的研究活动性质，包括学术和工业实验室之间的密切合作，将为不同的研究人员和学生社区提供广泛的跨学科培训，包括代表性不足的群体。技术摘要嵌段共聚物作为共混相容剂和纤维施胶的广泛商业应用受到昂贵和严格的聚合方法的限制，这些聚合方法需要以离散的嵌段形式控制共聚单体的序列。作为一种变革性的方法，PI提出了一种简单的物理聚合物化学替代方案，通过在非均相、半结晶、凝胶状态下的后聚合官能化，在聚醚醚酮(PEEK)中产生受控的嵌段微结构。该项目的基本重点将是推动这一新工艺可实现的嵌段性极限，为定向界面相互作用/反应扩展官能化化学的合成工具箱，并了解嵌段官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。这种学术和产业的合作将解决为基于PEEK的共混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嵌段嵌段共聚物相媲美。该项目的总体基本目标是了解相容剂微观结构(块状与随机)在多相体系中对界面性质的作用。该项目研究活动的跨学科性质，从纯化学、材料可回收利用到高分子工程，将为渴望为我国确保更健康、更可持续的全球社会做出贡献的不同公民和研究人员社区提供过多的教育机会。该奖项反映了NSF的法定使命，并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，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.