Radiative Cooling by Green(er) Solvents-Upcycled Polyvinyl Chloride From Drug Blisters Waste

Among the environmental challenges of the modern world, plastic waste is particularly concerning, especially compared to a global recycling capacity of less than 15% and considering the need for energy saving as well. Composite materials such as single-use drug blisters are especially difficult to recycle due to their multi-material composition and extensive presence of poly(vinyl chloride). Here, we present an approach to retrieve and upcycle poly(vinyl chloride) waste derived from pharmaceutical blister waste into systems for radiative cooling—a promising passive thermal management strategy exploiting the thermal emission of materials toward outer space – converting an environmental issue into a valuable resource. We used acetone to separate poly(vinyl chloride) from drug blisters, and fabricated white, strongly sunlight-scattering membranes through nonsolvent induced phase separation using either traditional or green(er) solvents. Membranes were used in tandem with aluminum foil as radiative coolers, demonstrating the capability to limit temperature increases to +2°C with respect to ambient under direct mid-latitude summer sunlight and to +1.4°C using a solar simulator in mid-latitude winter climate. In the absence of sunlight, the system provides sub-ambient cooling between −2.5°C and −3°C. These results are promising toward greater use of recycled polymer materials for radiative cooling applications.