CAREER: Recycled Polymers of Enhanced Strength and Toughness: Predicting Failure and Unraveling Deformation to Enable Circular Transitions

这项教师早期职业发展（Career）资助的研究旨在了解回收聚合物的变形和破坏，被称为回收物。由于原始塑料的机械性能较差，回收物无法取代它们。这导致了资源枯竭、浪费和污染的挑战。初步研究表明，通过引入不同的自组装相来改变可回收材料的内部结构，可以改善其机械性能。然而，由于其复杂性，研究这些自组装结构的变形和破坏是非常具有挑战性的，这是使其更广泛采用和使用所必需的。该奖项支持通过复杂的实验和人工智能来预测回收材料中变形和破坏的基础研究。这些发现将加强科学认识，促进先进的可回收材料的开发，使美国多个工业受益，促进可持续性，并保护国家资源。与此同时，教育、外联和更广泛的影响活动旨在通过提供新的工程技能和改善边缘化个人的职业前景来塑造多样化和敏捷的美国劳动力，重点是让被监禁的个人重新进入劳动力市场。该基金旨在通过综合实验和计算方法支持研究，以提高对可回收材料变形和失效的理解，这些可回收材料表现出提高强度和韧性的自组装内部形态。这项研究工作的新力学发现将使具有类似机械性能的再生塑料替代原始塑料，从而实现循环过渡，并解决紧迫的塑料污染挑战。通过利用内置的能量潜力，存在于异质回收物的不混相聚合物共混物中，它们的内部结构将被改变。通过这种方式，热泳诱导的具有相分离、自组装三维形态的增强力学性能的复合材料将被开发出来。这些回收物的结构-性能空间将被探索，其复杂的破坏和变形将被研究，同时开发复杂的实验力学仪器来支持这些努力。将高通量、大数据生成实验与最先进的人工智能算法相结合，将能够预测失效演变，并了解强度和韧性增强机制。这些预测将揭示非均相聚合物复合材料的新的变形机制。这些知识还将有助于建立新的、可靠的裂纹分支、弯曲和分叉标准，这些标准几十年来一直困扰着研究人员。研究工作将与教育、推广和更广泛的影响活动密切相关，这些活动将通过在力学课程中嵌入可持续性，并吸引受正义影响的青年参与工程科学，从而实现综合和包容的力学教育。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。

This Faculty Early Career Development (CAREER) grant supports research that aims to understand the deformation and failure of recycled polymers, known as recyclates. Recyclates have been unable to replace virgin plastics because of their poor mechanical performance. This leads to resource depletion, waste, and pollution challenges. Preliminary work suggests that altering the internal structure of recyclates, by introducing distinct, self-assembled phases within them, improves their mechanical performance. However, investigating the deformation and failure of these self-assembled structures, which is necessary to enable their wider adoption and use, is extremely challenging due to their complex nature. This award supports fundamental research to predict how deformation and failure occurs in recyclates through sophisticated experiments and artificial intelligence. The findings will enhance scientific understanding and foster the development of advanced, recycled materials that could benefit multiple U.S. industries, advance sustainability, and conserve national resources. In parallel, the education, outreach, and borader impact activities aim to shape a diverse and agile U.S. workforce by offering new engineering skills and improving career prospects of marginalized individuals, with emphasis on individuals reentering the workforce from incarceration. This grant aims to support research that advances understanding of the deformation and failure of recyclates exhibiting self-assembled internal morphologies of improved strength and toughness through an integrated experimental and computational approach. The new mechanics discoveries by this research effort will enable the substitution of virgin plastics with recycled ones of similar mechanical performance resulting in circular transitions and addressing the pressing plastic pollution challenge. By exploiting the built-in energy potential present in immiscible polymer blends of heterogeneous recyclates, their internal architecture will be altered. This way, composites of enhanced mechanical properties with phase-separated, self-assembled three-dimensional morphologies, induced by thermophoresis, will be developed. The structure-property space of these recyclates will be explored and their complex failure and deformation will be investigated, while developing sophisticated experimental mechanics instrumentation to support such efforts. Coupling high-throughput, big-data generating experiments with state-of-the-art artificial intelligence algorithms will enable the prediction of failure evolution and the understanding of strength and toughness enhancement mechanisms. These predictions will unravel new deformation mechanisms for heterogeneous polymer composites. Such knowledge will also enable the establishment of new, reliable criteria for crack branching, curving and bifurcation, which have eluded researchers for decades. The research efforts will be closely tied to education, outreach, and broader impact activities which will work towards an integrated and inclusive mechanics education, by embedding sustainability in mechanics courses and engaging justice-impacted youth with engineering science.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.