Chemical upcycling of high-density polyethylene into upcycled waxes as rheology modifiers and paper coating materials.

Chemical upcycling of plastic waste from landfills to value-added products offers both economic and environmental benefits. Reported here is a simple method to convert high-density polyethylene (HDPE) into upcycled waxes in a very high yield (up to 93%). This selectivity is achieved by reducing the degradation temperature of HDPE via the addition of an inexpensive and reusable sodium chloride. These upcycled waxes had performance comparable to those of commercial rheology modifiers. In addition, kraft paper coated with these upcycled waxes exhibited excellent water- and oil resistance. A preliminary revenue analysis showed that this innovation allows plastic-to-wax to conversion with a three-fold revenue benefit over traditional ways of producing pyrolysis waxes from plastics. Also, sodium chloride reduces the pyrolysis temperature, thus reducing energy consumption and greenhouse gas emissions, supporting cleaner production, a circular economy, and generating less environmental pollution. The underlying concept reported herein can be extended to major plastics by reducing the degradation temperatures of plastics, thereby obtaining even better control over the pyrolysis products. Thus, these findings have the potential to enhance the circular economy of plastics and protect our environment from plastic waste. SYNOPSIS. Chemical upcycling of post-consumer polyethylene via a sodium chloride-catalyzed process. [Display omitted] • Demonstrated table salt-assisted pyrolysis of high-density polyethylene. • Converted polyethylene into upcycled waxes at mild temperatures and in high-yield. • Used upcycled waxes as rheology modifiers and water-proof coating material. • Performed preliminary revenue analysis. [ABSTRACT FROM AUTHOR]