Innovations Toward the Valorization of Plastics Waste

Abstract

Plastics are an extremely important class of materials that are prevalent in all facets of society; however, their widespread use over time, combined with limited end-of-life strategies, has led to increasing levels of waste accumulation. Although currently considered a burden, plastics waste is potentially an untapped feedstock for numerous chemical and manufacturing processes. In this review, we discuss the state of the art of approaches for valorization of plastics waste from a materials research perspective, including previous efforts to utilize plastics waste and recent innovations that have opportunities to add significant value. Although additional progress is necessary, we present several diverse capabilities and strategies for valorization that, when brought together, address end-of-life challenges for plastics at every stage of design and product consumption. In short, a materials research–based framework offers a unique perspective to address the urgent issues posed by plastics, unlocking the potential of polymers and plastics waste.

Antioxidant-induced transformations of a metal-acid hydrocracking catalyst in the deconstruction of polyethylene waste

“…, barrier properties, high strength-to-weight ratio). 1,2 This accelerating demand for plastics is accompanied by manufacturer and consumer needs for an amalgam of features ( e.g. , visual appeal, thermal stability, versatile processability) that drive rising plastics diversity.…”

“…contribute to highly varied waste streams that challenge the creation of economic value and reduction of waste accumulation. 1,3,4 For example, within sorted, post-consumer high-density polyethylene (HDPE), numerous colorants, processing aids, macromolecular architectures, fillers, and crystallinities can be present and can introduce significant heterogeneity among recycling inputs (to either mechanical or chemical processes) that limits product value and process scalability. 4–6 Valorization routes that consider both the macromolecular and the compositional diversity inherent to all plastics are likely to become widespread strategies that address real, discarded plastics.…”

“…14 In another instance, dissolution- or solvolysis-based approaches can concentrate certain toxic additives like phthalate plasticizers, precluding industrial adoption. 7,15 Although the impact of additives on valorization is widely accepted as fact or implied by experimental studies, 1,16–18 information about how common additives affect certain emergent chemical recycling strategies is needed to guide innovation in both plastics formulation and catalytic design. As scientific advances continue to address increasingly complex waste, novel processes that are tolerant to a wide range of additives are highly desirable.…”

“…As scientific advances continue to address increasingly complex waste, novel processes that are tolerant to a wide range of additives are highly desirable. 1,4,19…”

“…, hydrocracking and hydrogenolysis) has gained increasing attention as a strategy for the deconstruction of plastics. 1,18,20–22 This technology is particularly well suited to valorize polyolefins, which represent the largest percentage (by weight) of plastics consumed globally. 2 In hydroconversion processes, supported noble metal catalysts ( e.g.…”