EFRI E3P: Reincarnation of Polymers for the Circular Economy

美国回收的塑料垃圾不到10%。低回收利用率造成的问题包括：1)废塑料泄漏到自然环境中，并伴随着碎裂成微塑料颗粒污染，对生态系统和人类健康产生不利影响；2)石油和天然气供应枯竭--需要使用大量能源来制造新塑料；3)与使用回收材料相比，温室气体排放增加。微塑料污染问题尤其令人担忧，因为这些微小的塑料颗粒正在进入人类食物链，而这些非常小的塑料颗粒的微塑料消费的影响目前尚不清楚。此外，一些分析表明，加强回收将带来巨大的就业增长；可以创造100多万个就业机会。在这个新兴前沿研究和创新项目中，一个跨学科和多样化的团队将致力于改造塑料行业，以消除报废废物。革命性的分类、清洁和转化废塑料的方法带来了变革性的结果；随着更多的塑料被重复使用而不是扔进垃圾场，目前的“寿命终结”思维变成了整体的“周期终结”思维。通过这项研究开发的知识和技术将使塑料回收利用率更高，更多的回收创造就业机会，同时帮助保护环境和人类健康。投资于改进的回收技术将有助于美国在瞬息万变的全球经济中保持竞争力。参与方案活动是包容的，并通过与社区可持续发展方案的新的跨学科互动以及通过为K-12和本科生提供外展方案来促进。一个多元化团队将与密歇根部落学院合作，支持美洲原住民社区有意义地参与STEM研究。通过将传统知识融入到项目教学中，将培养人们对可持续发展问题的深刻和不同文化的认识。该项目的目标是开发和展示回收塑料的新方法。该项目的范围包括解聚聚合物并将产品重新聚合为有价值的材料的新方法。控制实验辅之以化学动力学模型、分子尺度模拟和机器学习是主要的方法。将使用生命周期分析(LCA)方面的专门知识来评估和确定新的创新方法的效用。通过解聚的化学循环是通过化学和生物化学催化的级联转化来完成的。与化学科学中迅速出现的创新趋势相一致，将通过对化学氧化随后酶催化脱羧基生成石脑油(混合烷烃)的案例研究，展示化学催化和酶催化转化的协同组合。由此产生的低温层叠方法将与目前最先进的热解方法进行比较；生命周期评价将指导工艺改进，并用于评估这种新的层叠方法是否提供了改进的可持续性指标。直接比较高温热解过程和低温级联过程可以极大地促进塑料回收领域的知识；到目前为止，还没有这样的综合评估。然而，关于这两条道路中哪一条值得未来重视的影响是深远的。将展示组合反应器-分离器的创新使用，预计这将是从废塑料中生产单体的一种更好的方法。再聚合将作为一种手段，将寿命即将结束的塑料“转世”为全新的、高价值的特种聚合物，供其来生使用。废旧聚乙烯的氧化将用于生产二元酸，而对废聚对苯二甲酸乙二醇酯进行氨解的创新用途将提供芳香族二胺。产生的单体将被并入新形成的聚合物中，包括聚酯、聚酰胺、聚芳酰胺、聚酯酰胺和聚酯芳胺。这些产生的聚合物比回收的废塑料贵得多(2-3倍)，提供了一种经济激励，可以有效地提高回收率。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。

The United States recycles less than 10% of generated plastic waste. Low recycling rates create problems including: 1) leakage of waste plastic into the natural environment and accompanying fragmentation into microplastic particulate pollution that negatively affects ecosystems and human health, 2) depletion of our oil and natural gas supplies - the need to use lots of energy to make new plastics, and 3) increased greenhouse gas emissions compared to using recycled materials. The microplastics pollution problem is particularly concerning because these small plastic particles are entering the human food chain, and the effects of microplastic consumption of these very small plastic particles is currently unknown. Furthermore, several analyses have shown enhanced recycling will lead to dramatic job growth; upwards of a million jobs could be created. In this Emerging Frontiers in Research and Innovation project an interdisciplinary and diverse team will work to transform the plastics industries to eliminate end-of-life waste. Revolutionary approaches to sorting, cleaning, and transforming waste plastics enables a transformational outcome; present “end of life” thinking becomes holistic “end of cycle” thinking as more plastics are repeatedly used rather than thrown into a dump. The knowledge and technologies developed through this research will enable greater rates of plastics recycling, more recycling creates jobs while helping to protect the environment and human health. Investing in improved recycling technologies will help the USA remain competitive in the ever-changing global economy. Participation in programmatic activities is inclusive and fostered by novel cross-disciplinary interaction with Community Sustainability programs and through delivery of outreach programs for K-12 and undergraduate college students. A Diversity Team will work in partnership with the tribal colleges of Michigan, which are Minority-serving institutions, to support meaningful participation in STEM research by the Native American community. A deep and culturally diverse awareness of sustainability issues will be fostered through incorporation of traditional learnings into program pedagogy.The goal of the project is to develop and demonstrate new approaches to recycling plastics. The scope of the project includes novel ways to depolymerize polymers and repolymerize the products into valuable materials. Controlled experimentation complemented by chemical kinetic models, molecular-scale simulations, and machine learning are the primary methods used. Specialized expertise in life cycle analysis (LCA) will be used to assess and establish the utility of the new and innovative approaches. Chemical recycling through depolymerization is accomplished through cascading of chemically and biochemically catalyzed transformations. Consistent with a rapidly emerging innovation trend in the chemical sciences, synergistic combinations of chemically and enzymatically catalyzed transformations will be demonstrated through the case study of chemical oxidation followed by enzymatically catalyzed decarboxylation to create naptha (mixed alkanes). The resulting low-temperature cascaded approach will be compared to the present state-of-the-art of thermal pyrolysis; LCA will guide process improvements and be used to assess if this new cascading approach provides improved sustainability metrics. A direct comparison of a high-temperature pyrolysis process with a low-temperature cascading pathway can substantially advance knowledge in the plastic recycling field; to date, no such comprehensive evaluation is available. However, the implications regarding which of the two pathways deserves future emphasis are profound. The innovative use of combined reactor-separators will be demonstrated and is expected to be a superior approach to producing monomers from waste plastics. Repolymerization will be pursued as a means of “reincarnating” end-of-life plastic into brand new, high-value, specialty polymers for use in their next life. Oxidation of waste polyethylene will be used to produce dicarboxylic acids, and the innovative use of ammonolysis on waste polyethylene terephthalate will provide aromatic diamines. Resulting monomers are to be incorporated into newly formed polymers including polyesters, polyamides, polyaramids, polyesteramides, and polyesteraramids. These resulting polymers are considerably more expensive (2-3x) than the reclaimed waste plastic, providing an economic incentive that can effectively increase recycling rates.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.