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.
