CAS-SC: Tuning Hydrocarbon Products from Temperature-Gradient Thermolysis of Polyolefins and the Subsequent Upcycling to Functional Chemicals

塑料废物是一个全球性的挑战，必须解决，以实现可持续的未来。PI开发了一种“级联降解和升级回收”技术（“Deg-Up”），这是一种将塑料废物转化为高价值化学品和材料的新兴有效手段。在降解由聚乙烯（PE）和聚丙烯（PP）制成的两种最常见的大批量商业塑料中，温度梯度热分解（塑料分子的受控热分解）在将它们转化为一般用途的平台中间体化学品方面非常有效。在平台中间化学品的升级循环中，PE和pp衍生产品对于随后的转化生产高价值材料（例如，肥皂，洗涤剂，表面改性剂等）特别有用。从低成本的塑料废物中生产高价值的表面活性剂可以为解决现有的快速积累的塑料废物提供重大的经济激励。PE和PP的可控“Deg-Up”将是该项目的重点，它将为生产可持续的表面活性剂提供新的方法，同时降低能耗和碳排放。PE和pp衍生中间分子的下游功能化将为未来利用其他塑料废物原料“废物转化为价值”的发展奠定基础。该项目的教育部分与“塑料可持续性”概念高度融合，将培训各级学生，包括代表性不足的当地K-12和大学生，与邻近的历史悠久的黑人学院和大学合作，并在阿巴拉契亚地区制定可持续的塑料废物清除计划。大量堆积的塑料垃圾需要一个比垃圾填埋场或海洋更好的归宿。化学升级回收是将低价值塑料废物转化为高价值化学品和材料的一种有吸引力的方法。该项目利用塑料废物作为化学原料，很像“原油”，只是它不需要钻探或开采。包括聚乙烯（PE）和聚丙烯（PP）在内的两种大批量塑料将转化为高价值表面活性剂。该项目将(a)提供对温度梯度热裂解的理解，以生产受控降解中间体；(b)开发升级回收策略，以生产增值离子和非离子表面活性剂。本项目的主要研究任务包括：1)利用温度梯度热裂解降解PE和PP； 2)将热裂解产物与离子端基功能化，形成两亲分子用作表面活性剂；3)将热裂解产物功能化成非离子分子。拟议的研究将影响聚合物和表面活性剂领域，并使塑料升级回收成为高价值化学品。升级回收战略消除了塑料废物，以减少的形式延长了碳的使用寿命，减少了碳排放，减轻了环境污染。教育方面的影响包括培训代表性不足的K-12和阿巴拉契亚地区的第一代大学生。教育部分分享了“聚合物可持续性”的中心主题，并与研究高度结合。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 SUMMARY Plastic waste is a global challenge that must be addressed to achieve a sustainable future. The PI has developed a technique of “cascade degradation and upcycling” (“Deg-Up”) that represents an emerging effective means to convert plastic waste into high-value chemicals and materials. In the degradation of the two most common high-volume commercial plastics made of polyethylene (PE) and polypropylene (PP), temperature-gradient thermolysis (a controlled thermal breakdown of the plastic molecules) is highly effective in converting them into platform intermediate chemicals for general uses. In the upcycling of platform intermediate chemicals, PE and PP-derived products are particularly useful for subsequent conversion to produce high-value materials such as surfactants (e.g., soaps, detergents, surface modifiers, etc.). The output of high-value surfactants from low-cost plastic waste can provide significant financial incentives to address the existing fast-accumulating plastic waste. The controlled “Deg-Up” of PE and PP, which will be the focus of this project, will offer new approaches to producing sustainable surfactants with reduced energy consumption and carbon emissions. Downstream functionalization of PE and PP-derived intermediate molecules will pave the foundation for the future development of “waste-to-value” using other plastic waste feedstocks. Highly integrated with the concept of “plastic sustainability”, the educational component of the project will train students at all levels including underrepresented local K-12 and college youth, work with neighboring Historically Black Colleges and Universities, and develop sustainable plastic waste removal programs in Appalachia. PART 2: TECHNICAL SUMMARY The vast amount of accumulated plastic waste requires a better ending point than landfills or oceans. Chemical upcycling is an attractive method to bring low-value plastic waste into high-value chemicals and materials. This project utilizes plastic waste as a chemical feedstock, much like “crude oil” except that it requires no drilling or mining. Two high-volume plastics, including polyethylene (PE) and polypropylene (PP), will be converted to high-value surfactants. The project will (a) provide an understanding of temperature-gradient thermolysis for producing controlled degradation intermediates and (b) develop upcycling strategies to produce value-added ionic and non-ionic surfactants. Three main research tasks of the project include: 1) employment of temperature-gradient thermolysis to degrade PE and PP, 2) functionalization of the thermolysis products with ionic end groups to form amphiphilic molecules for use as surfactants, and 3) functionalization of the thermolysis products into non-ionic molecules. The proposed research will impact the fields of polymers and surfactants and enable the upcycling of plastics into high-value chemicals. The upcycling strategy removes plastic waste, elongates the lifespan of carbon in a reduced form, decreases carbon emissions, and mitigates environmental pollution. The educational impacts include training underrepresented K-12 and first-generation college students in Appalachia. The educational components share the central theme of “polymer sustainability” and are highly integrated with research. .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.