EFRI E3P: End of Life Plastics as Starting Materials for Filtration and Barrier Applications

聚乙烯(PE)、聚丙烯(PP)、聚氯乙烯(PVC)和聚对苯二甲酸乙二醇酯(PET)是造成环境污染的主要塑料类型。在这个项目中，研究人员的目标是通过三种方法将塑料垃圾“上行”(而不是回收)成用于过滤和屏障应用的增值产品。他们将通过控制聚氯乙烯的降解和交联来设计防水、隔热和电绝缘的弹性体，将废弃的聚氯乙烯转化为氯丁橡胶®替代材料，可以通过3D打印形成密封件、垫圈和各种其他产品。这提供了一条获得有价值橡胶的新途径，防止有毒化合物的释放，并减少对目前橡胶制造中使用的危险原料的依赖。研究人员将设计新的绿色溶剂，以克服溶解和再加工PP和PET的挑战，这将允许更安全地处理/加工聚合物溶液，推动工艺强化，并减少当前加工条件带来的健康和安全风险。他们将利用废弃的PP或PET制造通常用于家用空气过滤器和水处理膜机械支架的无纺布，这将改善空气和水过滤的环境影响，以帮助确保建筑物和饮用水的清洁空气。此外，对水生生态系统中塑料的实地采样将为升级循环方法提供真实的废物样本，并估计这些方法减少塑料污染的能力。这项拟议的研究将由研究生和本科生进行，他们将合作制定研究计划，通过暑期沉浸体验指导当地HBCU学生，并向来自代表不足的群体的当地K-12学生进行STEM外展。该项目旨在为将常见废塑料，特别是PP、PVC和PET转化为增值产品创造变革性的新途径。研究人员假设：(1)如果废旧聚氯乙烯通过部分脱氯化氢和随后的交联以受控方式进行化学处理，那么可以直接生产性能可调的有价值的弹性体，而不需要依赖新的石油基单体；(2)如果围绕具有甘油骨架的分子开发出一种使用实验和计算方法相结合的新的分子设计方法，那么PET和PP可以在更安全的处理/加工条件下被溶解和再加工；(3)如果从废旧中回收的PET和PP纤维用于非织造布，与商业无纺布上合成的聚偏氟乙烯(PVDF)膜相比，它们不会改变空气过滤器的性能和在这些织物上合成的PVDF膜的性能。了解溶剂选择、添加剂、增塑剂、染料、填料等对聚氯乙烯脱氯化氢、聚偏氟乙烯膜分离性能和家用空气滤清器性能的影响。将获得关于这些过程在消除进入水生态系统的废塑料方面的有效性的新知识。技术经济分析将产生关于这些更新塑料的新方法的商业可行性的知识，并为进一步的改进提供指导。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。

Polyethylene (PE), polypropylene (PP), poly(vinyl chloride) (PVC), and polyethylene terephthalate (PET) are types of plastic that make major contributions to the amount of pollution the environment. In this project, the investigators aim to “upcycle” (rather than recycle) plastic wastes into value-added products for filter and barrier applications through three approaches. They will design waterproof, thermally and electrically insulating elastomers through controlled PVC degradation and crosslinking to transform the waste PVC into Neoprene®-substitute materials that can be 3D printed to form seals, gaskets, and a variety of other products. This provides a new pathway to valuable rubbers, prevents the release of toxic compounds, and reduces reliance on the hazardous feedstocks currently used in rubber manufacture. The investigators will engineer new green solvents to overcome the challenges of dissolving and reprocessing PP and PET, which will allow for safer handling/processing of polymer solutions, drive process intensification, and reduce health and safety risks posed by the current processing conditions. They will make non-woven fabrics commonly used for household air filters and mechanical supports for water treatment membranes, from waste PP or PET which will improve the environmental impact of air and water filtration to help ensure clean air for buildings and drinking water. Additionally, field sampling of plastic in the aquatic ecosystems will provide real waste samples for the upcycling methods, and an estimate of the capacity for these approaches to reduce plastic pollution. The proposed research will be carried out by graduate and undergraduate students, who will collaboratively develop research plans, mentor local HBCU students through a summer immersion experience, and perform STEM outreach to local K-12 students from underrepresented groups.This project aims to create transformative new avenues for converting common waste plastics, specifically PP, PVC, and PET, into value-added products. The investigators hypothesize: (1) if waste PVC is chemically processed in a controlled manner via partial dehydrochlorination and subsequent crosslinking, then valuable elastomers with tunable properties can be directly produced without relying on new petroleum-based monomers, (2) if a new approach to molecular design using combined experimental and computational methods is developed around molecules with glycerol skeletons, then PET and PP can be dissolved and reprocessed under safer handling/processing conditions, and (3) if PET and PP fibers recovered from waste are used in non-woven fabrics, they will not change air filter performance properties and performance of polyvinylidene fluoride (PVDF) membranes synthesized on top of these fabrics compared to those on top of commercial non-woven fabrics. A fundamental understanding will be gained on how solvent choice, additives, plasticizers, dyes, fillers, etc. impact PVC dehydrochlorination, PVDF membrane separation properties, and household air filter properties. New knowledge will be gained about the effectiveness of these processes on eliminating waste plastic from entering aquatic ecosystems. A techno-economic analysis will generate knowledge on the commercial feasibility of these new ways of upcycling plastics and provide guidance for further improvements.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.