Chemical Recycling of Polystyrene to Valuable Chemicals via Selective Acid-Catalyzed Aerobic Oxidation under Visible Light

Microwave-Assisted Catalytic Upcycling of Plastic Wastes over Heterojunction-Structured Layered Triple Oxides

Chemical upcycling of plastic wastes into valuable chemical feedstocks and simultaneous mitigation of environmental deterioration are fascinating but remain extremely challenging. Herein, we report microwave-assisted valorization of plastic wastes into carbon nanotubes (CNTs) and hydrogen (H2) over heterojunction-structured mixed metal oxides. Specifically, the CoNiFe-based layered triple oxides (LTO) arrayed on Ni-foam (CoNiFe-LTO@foam) were constructed. The special heterojunction of the LTO endows high dielectric loss, facilitating efficient conversion of absorbed microwave energy into thermal energy. Most importantly, the synergistic effect of the multiple transition metal sites boosts the cleavage of carbon chains and dehydrogenation, thereby accelerating the reaction kinetics. As a result, the CoNiFe-LTO@foam achieves an H2 selectivity of ∼95 vol % with the yield of ∼69 mmol · g plastic - 1 for upcycling polyethylene in 25 cycles of measurement. Simultaneously, the CNTs attain a yield of ∼35%, which can be used for aqueous chloride-ion batteries. Additionally, the CoNiFe-LTO@foam enables facile recovery of CNTs and prevents the loss of catalytic sites, facilitating upcycling of various real-world plastic wastes. Our work thus highlights the innovations of an advanced catalytic system for forming a closed loop of plastic C/H and achieving the ultimate goal of a carbon-neutral society.

Facile visible-light upcycling of diverse waste plastics using a single organocatalyst with minimal loadings

The escalating plastic waste crisis stems from limitations in conventional recycling methods, which are energy-intensive and produce lower-quality materials, leaving a substantial portion unrecycled. Here, we report a versatile organo-photocatalytic upcycling method employing an easily accessible phenothiazine derivative, PTH-3CN, to selectively deconstruct a wide array of commodity polymers-including polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyurethanes (PU), polycarbonates (PC), and other vinyl polymers-into valuable small molecules with minimal catalyst loading (as low as 500 ppm). Operating under mild conditions with visible light and ambient air, this protocol requires no additional acids or metals and adapts effectively to mixed and post-consumer plastic waste. Mechanistic analysis reveals that PTH-3CN serves as a precatalyst, decomposing into active triarylamine species that drive efficient degradation likely through a consecutive photoinduced electron transfer mechanism. This approach offers a promising, scalable route for sustainable plastic upcycling with broad applicability.

Floatable organic-inorganic hybrid-TiO2 unlocks superoxide radicals for plastic photoreforming in neutral solution

Plastic photoreforming offers a compelling technology to address the global issue of the large amount cumulative plastic waste by converting it into valuable fuels and chemical feedstocks. However, constrained by insufficient mass and energy transfers, the existing hydrophilic plastic photoreforming systems heavily rely on the unsustainable chemical pre-treatments in corrosive solutions. Herein, we demonstrate a conceptual plastic photoreforming system based on a floatable hydrophobic organic-inorganic hybrid-TiO2 photocatalyst, which unlocks superoxide radical as the major oxidizing species and forms a four-phase interface among photocatalyst, plastic substrate, water and air, thus greatly enhancing the mass and energy transfers. Consequently, the photoreforming yield rates in neutral aqueous solutions are increased by 1-2 orders of magnitude for typical plastic including polyethylene, polypropylene, and polyvinyl chloride without applying pre-treatments, whilst producing high-value C2H5OH with a selectivity of over 40%. We believe this work reveals a feasible route to sustainable plastic photoreforming.

A Mind Map to Address the Next Generation of Artificial Photosynthesis Experiments

Artificial photosynthesis (APS) is using light for uphill chemical reactions that converts light energy into chemical energy. It follows the example of natural photosynthesis, but offers a broader choice of materials and components, which can enhance its performance it terms of application conditions, stability, efficiency, and uphill reactions to be carried out. This work presents here first the status of the field, just to focus afterward on the current problems seen at the forefront of the field, as well as discussing some general misunderstandings, which are often repeated in the primary literature. Finally, this perspective article is daring to define some grand challenges, which have to be tackled for the translation of APS into society.

Visible Light-Induced C─C Bond Cleavage for the Construction of Ketone Using Molecular Oxygen

The selective cleavage of carbon-carbon bonds by photocatalysis with the participation of oxygen for ketone synthesis and drug derivatization is reported. In this oxidation-based ketone formation reaction, molecular oxygen complexes with the substrate, which is subsequently photoexcited to generate a charge transfer (CT) state. This CT state facilitates energy transfer with molecular oxygen, producing singlet oxygen, which facilitates hydrogen atom process and promotes the subsequent cleavage of the carbon-carbon bond, ultimately leading to the formation of aryl ketone compounds. 48 aryl ketone compounds and pharmaceutical derivatives were synthesized using this method. A notable feature of this reaction is its catalyst-free, additive-free, and transition metals-free nature combined with green, mild, and environmentally friendly reaction conditions enabling high yields.

Synergistic Co-Recycling: Selective Oxidation of Polyethylene to Dicarboxylic Acids over Spent LiCoO2 Cathodes

The escalating production of lithium-ion batteries and plastics poses critical challenges to environmental integrity and resource sustainability. Here, we report a synergistic co-recycling strategy for spent lithium cobalt oxide (LCO) cathodes and waste polyethylene (PE), leveraging the catalytic properties of LCO to oxidize PE into high-value dicarboxylic acids. Through a combination of density functional theory calculations, electron spin resonance, and in situ infrared spectroscopy, we reveal that lithium-deficient LCO undergoes a spin-state transition of Co3+ to a high-spin state, facilitating the activation of oxygen and the generation of singlet oxygen. This reactive oxygen species drives the selective oxidation of PE via hydrogen atom transfer, achieving dicarboxylic acid yields of up to 77.5 wt%, markedly exceeding previous benchmarks. Validation with real-world plastic waste and spent batteries underscores the feasibility of this approach, presenting a sustainable paradigm-shift solution for the efficient management of lithium-ion batteries and plastic waste in a circular economy.

Catalytic Upgrading of Plastic Wastes into High-Value Carbon Nanomaterials: Synthesis and Applications

The surge in waste plastics has placed a serious burden on the global ecosystem. Traditional recycling methods are insufficient to handle the growing volume of plastic waste, highlighting the urgent demand for innovative recycling technologies. Transforming plastics into high-value carbon nanomaterials is a simple and efficient resource recovery strategy, especially effective for handling mixed or hard-to-separate plastic waste. This method not only simplifies the sorting of discarded plastics but also offers significant advantages in recovery efficiency and processing convenience. This review systematically summarized various technologies for converting plastics into carbon nanomaterials, focusing on the catalytic mechanisms of different conversion methods. We also analyzed how various catalysts, catalytic temperatures, and metal-support interactions affect the yield and quality of carbon nanomaterials. Additionally, the potential applications of carbon nanomaterials in environmental remediation, energy storage, and catalysis are also evaluated. The ongoing challenges and future research directions in this field are critically discussed, which will ultimately facilitate more effective resource recovery from plastics and contribute to the realization of a circular economy. We believe that this review will inspire more creativity in designing such win-win reaction systems to realize a "waste treat waste" concept.

Selective Degradation of Polyethylene Terephthalate Plastic Waste Using Iron Salt Photocatalysts

Plastic pollution poses a significant challenge to environmental conservation. Efficient recycling of plastic is a key strategy to address this issue. Polyethylene terephthalate (PET), commonly found in plastic bottles, represents a substantial portion of plastic waste. Consequently, the efficient degradation and recycling of PET is crucial for the sustainable development of society. However, the implementation of methods for PET depolymerization and recycling typically necessitates alkaline/acidic pre-treatment and significant energy input for heating. Here, we propose a gentle, and highly efficient photocatalysis approach for selectively degrading PET plastic waste into terephthalic acid (TPA) in high yield (up to 99 %) using cost-effective iron salts. Notably, this method achieved excellent selectivity with high TON and TOF values, applying oxygen or air as environmentally friendly oxidants. In addition, the solvent can be recycled without compromising the TPA yield, and large-scale reactions can be performed smoothly.

Can the Hock Process Be Used to Produce Phenol from Polystyrene?

Polystyrene (PS) is a widely used thermoplastic polymer, but its very low recycling rate has motivated consideration of chemical conversion strategies to convert waste PS into value-added products. Oxidation methods have been widely studied, but they typically generate benzoic acid, a product with a relatively low market demand. Phenol is a higher volume chemical that would be an appealing target, but no methods currently exist for the conversion of PS into phenol. The repeat unit in PS closely resembles cumene, the primary feedstock used to produce phenol through the Hock process. Here, we investigate prospects for adapting the Hock process to PS, generating hydroperoxides through the autoxidation of benzylic C-H bonds followed by the acid-promoted rearrangement of the hydroperoxides to afford phenol and a partially oxygenated polymer. Experimental and computational studies of dimeric and trimeric PS model compounds show that neighboring phenyl rings impose conformational constraints that raise the barrier to hydrogen-atom transfer from the tertiary benzylic C-H bond. These effects are also evident with PS and contribute to lower yields of phenol when PS is subjected to Hock process conditions. These results provide valuable insights that have important implications for other efforts that seek to adapt small-molecule reactivity to polymeric feedstocks.

Ultratough Thermoplastic Elastomers Based on Chemically Recyclable Cycloalkyl-Substituted Polyhydroxyalkanoates

It remains a long-standing challenge for chemical recycling of polyhydroxyalkanoates (PHAs) to propiolactone-based monomers due to the high ring strain and many inevitable side reactions. In this contribution, a novel α-spiro-cyclohexyl-propiolactone (SHPL) has been designed with high reactivity toward ring-opening polymerization even at a catalyst loading of <1 ppm. The resulting poly(3-hydroxy-2-spiro-cyclohexylpropionate) (P3HSHP) exhibited high thermal stability with a Td of 364 °C and a high Tm of 272 °C. Meanwhile, it could be depolymerized back to SHPL in 86% yield without decarboxylation or elimination side products. Notably, SHPL could be exploited to construct high-performance thermoplastic elastomers (TPEs) via one-pot copolymerization with ε-caprolactone (CL). Particularly, the resulting gradient P(CL2000-grad-SHPL500) showcased an ultimate tensile strength of 58.8 ± 4.0 MPa, high stretchability of 1959 ± 53%, a record toughness of 600 MJ/m3, and high elastic recovery (>90%). This superior performance of SHPL could advance the development of new sustainable high-performance TPEs.

Activation of Molecular Oxygen and Selective Oxidation with Metal Complexes

ConspectusSelective oxidation with molecular oxygen is one of the most appealing approaches to functionalization of organic molecules and, yet at the same time, one of the most challenging reactions facing organic synthesis due to poor selectivity control. Molecular oxygen is a green and inexpensive oxidant, producing water as the only byproduct in oxidation. Not surprisingly, it has been used in the manufacturing of many commodity chemicals in the industry. It is also nature's choice of oxidant and drives a variety of oxidation reactions critical to life and various other biologic processes. While the past decades have witnessed great progress in understanding, both structurally and mechanistically, how nature exploits metalloenzymes, i.e., monooxygenases and dioxygenases, to tackle some of the most challenging oxidation reactions, e.g., methane oxidation to methanol, there are only a small number of well-defined, man-made metal complexes that have been reported to enable selective oxidation with molecular oxygen of compounds more relevant to fine chemical and pharmaceutical synthesis.In the past 10 years or so, our laboratories have developed several transition metal complexes and shown that they are capable of catalyzing selective oxidation under 1 atm of O2. Thus, we have shown that an Fe(II)-bisimidazolidinyl-pyridine complex catalyzes selective oxygenation of C-H bonds in ethers with concomitant release of hydrogen gas instead of water, and when the iron center is replaced with Fe(III), selective oxidative cleavage of C═C bonds of olefins becomes feasible. To address the low activity of the iron complex in oxidizing less active olefins, we have developed a Mn(II)-bipyridine complex, which catalyzes oxidative cleavage of C═C bonds in aliphatic olefins, C-C bonds in diols, and carboxyl units in carboxylic acids under visible light irradiation. Light is necessary in the oxidation to cleave an off-cycle, inactive manganese dimer into a catalytically active Mn═O oxo species. Furthermore, we have found that a binuclear salicylate-bridged Cu(II) complex enables the C-H oxidation of tetrahydroisoquinolines as well as C═C bond cleavage, and when a catalytic vitamin B1 analogue is brought in, oxygenation of tetrahydroisoquinolines to lactams takes place via carbene catalysis. Still further, we have found that a readily accessible binuclear Rh(II)-terpyridine complex catalyzes the oxidation of alcohols, and being water-soluble, the catalyst can be easily separated and reused multiple times. In addition, we recently unearthed a simple protocol that allows waste polystyrene to be depolymerized to isolable, valuable chemicals. A cheap Brønsted acid acts as the catalyst, activating molecular oxygen to a singlet state through complexation with the polymer under light irradiation, thereby depolymerizing the polymer.

Reassessing the Photochemical Upcycling of Polystyrene Using Acridinium Salts

Polystyrene (PS) is a commodity plastic recalcitrant to chemical recycling or upcycling processes. Approaches aimed at deconstructing PS by photocatalytic means struggle to generate high-energy species capable of cleaving the robust C-H and C-C bonds of PS. We show that 9-mesityl-10-methylacridinium perchlorate (MA) is capable of upcycling various grades of PS substrates into up to 40 % benzoic acid (BAc), formic acid (FA) and small proportions of acetophenone (ACP), under visible light (456 nm) or through solar radiation. Time-resolved emission and absorption spectroscopy evidence that a reaction with oxygen is the primary photochemical step in oxygen-saturated solutions, accounting for 77 % of the photons absorbed vs. 1 % for the direct reaction with PS (0.303 M in repeating units). These results are in agreement with a mechanism in which MA-mediated photo upcycling of PS to BAc occurs through the abstraction of benzylic H atoms by reactive oxygen species generated by energy or electron transfer from the excited state of MA. Addition of triplet O2 to these radicals, followed by intra- or inter-molecular hydrogen atom transfer (HAT) generates C- or O-centered radicals then undergoing β-scission or hydroperoxide fragmentation. The formation of intermediate oligomers functionalized by terminal carbonyl groups is demonstrated by both infrared analysis and MALDI TOF mass spectrometry. These oligomers undergo further photoinduced conversion even in the absence of MA, as evidenced by size exclusion chromatography analysis of the irradiated samples.

Selective Recycling of Mixed Polyesters via Heterogeneous Photothermal Catalysis

The selective recycling of mixed plastic wastes with similar structural units is challenging. While heterogeneous catalysis shows potential for selective recycling, challenges such as complex mass transfer at multiphase interfaces and unclear catalytic mechanisms have slowed progress. In this study, a breakthrough in recycling mixed polyester wastes is introduced using heterogeneous photothermal catalysis. By adding co-solvents, the difficulties associated with multiphase interfacial mass transfer are overcome. Grain boundary (GB)-rich CeO2 photothermal catalysts are used to selectively glycolyze mixed poly(ethylene terephthalate) (PET) and poly(bisphenol A carbonate) (PC) plastics into bisphenol A (BPA) and bis(2-hydroxyethyl) terephthalate (BHET), achieving yields of 97.8% and 93.4%, respectively. The high concentration of oxygen vacancies in GB-rich CeO2 catalysts adjusts the adsorption energy of intermediates, leading to more selective and efficient depolymerization compared to GB-poor CeO2 catalysts. The economic and environmental analysis demonstrates that this process, which utilizes heterogeneous photothermal catalysis, provides significant energy savings and carbon reduction, representing a major advancement in mixed plastic waste recycling.

Synthesis of Polyamides Bearing Directing Groups and Their Catalytic Depolymerization

We report a directing group (DG)-enabled strategy for polyamide depolymerization. Pyridine-based DGs selectively interact with In(III) catalysts, activating amide bonds for catalytic cleavage via alcoholysis. The process achieves efficient depolymerization of DG-introduced polyamides into recyclable monomers, providing a sustainable chemical recycling approach for robust polyamides.

Nitrogenative Degradation of Polystyrene Waste

Owing to massive production and poor end-of-life management, plastic waste pollution has become one of the most pressing environmental crises. In response to the mounting crisis, the past several decades have witnessed the development of numerous methods and technologies for plastic recycling. However, most of the current recycling technologies often produce low-quality or low-value products, making it difficult to recover the operating costs. To this end, we report a novel preoxygenation-induced strategy for the nitrogenative degradation of real-life polystyrene plastics into high-value aromatic nitrogen compounds in a cost-effective manner. Thus, expensive and highly demanding benzonitrile as well as benzamide were obtained in up to 74% overall isolated yield from polystyrene waste by using CuBr as the catalyst, O2 as the oxidant, and CH3CN as the nitrogen source. Detailed mechanistic investigations indicate that hydroxyl radicals from O2 activation play a role in this selective aerobic degradation process. Furthermore, multiple reaction pathways contribute to the formation of benzonitrile and benzamide.

Aerobic oxidation of alkylarenes and polystyrene waste to benzoic acids via a copper-based catalyst

The chemical recycling of polystyrene (PS) waste to value-added aromatic compounds is an attractive but formidable challenge due to the inertness of the C-C bonds in the polymer backbone. Here we develop a light-driven, copper-catalyzed protocol to achieve aerobic oxidation of various alkylarenes or real-life PS waste to benzoic acid and oxidized styrene oligomers. The resulting oligomers can be further transformed under heating conditions, thus achieving benzoic acid in up to 65% total yield through an integrated one-pot two-step procedure. Mechanistic studies show that the CuCl2 catalyst undergoes Ligand-to-Metal Charge Transfer (LMCT) to generate a chlorine radical, which triggers activation of the C-H bond and subsequent oxidative cleavage of C-C bonds. The practicality and scalability of this strategy are demonstrated by depolymerization of real-life PS foam on a gram scale, thus showing promising application potential in chemical recycling of PS waste.

Photocatalytic upcycling of polylactic acid to alanine by sulfur vacancy-rich cadmium sulfide

Photocatalytic conversion has emerged as a promising strategy for harnessing renewable solar energy in the valorization of plastic waste. However, research on the photocatalytic transformation of plastics into valuable nitrogen-containing chemicals remains limited. In this study, we present a visible-light-driven pathway for the conversion of polylactic acid (PLA) into alanine under mild conditions. This process is catalyzed by defect-engineered CdS nanocrystals synthesized at room temperature. We observe a distinctive volcano-shaped relationship between sulfur vacancy content in CdS and the corresponding alanine production rate reaching up to 4.95 mmol/g catalyst/h at 70 oC. Ultraviolet-visible, photocurrent, electrochemical impedance, transient absorption, photoluminescence, and Fourier-transform infrared spectroscopy collectively highlight the crucial role of sulfur vacancies. The surface vacancies serve as adsorption sites for lactic acid; however, an excessive number of vacancies can hinder charge transfer efficiency. Sulfur vacancy-rich CdS exhibits high stability with maintained performance and morphology over several runs, effectively converts real-life PLA products and shows potential in the amination of other polyesters. This work not only highlights a facile approach for fabricating defect-engineered catalysts but also presents a sustainable method for upcycling plastic waste into valuable chemicals.

Photochemical upcycling of polymers via visible light-driven C-H bond activation

The excessive use and improper disposal of plastics have placed a significant burden on the environment. To mitigate this impact, prioritizing the chemical upcycling of plastics is crucial. Unlike traditional thermochemical upcycling, which requires harsh conditions such as high temperatures and pressures, photochemical upcycling is viewed as a more environmentally friendly and cost-effective alternative. This includes using light to promote C-H bond activation to achieve the oxidative degradation of plastics, generating various valuable small molecules, or employing light-induced C-H bond activation for post-polymerization modification of post-consumer plastics to obtain polymers with enhanced properties. These methods are highly attractive approaches within the realm of chemical upcycling. This mini-review highlights the scientific breakthroughs in upcycling polymers through oxidative degradation and post-polymerization modification via visible light-driven C-H bond activation. In addition, the reaction mechanism compatibility as well as practical application have been emphatically discussed.

Photoreforming of Plastic Waste to Sustainable Fuels and Chemicals: Waste to Energy

The extensive accumulation of plastic waste has given rise to severe environmental pollution issues. Contemporary conventional recycling methods, such as incineration and landfilling, contribute significantly to pollutant emissions and carbon footprints, against the principles of sustainable development. Leveraging renewable solar energy to transform plastics into high-value chemicals and green fuels offers a more promising and sustainable approach to managing plastic waste resources. This comprehensive review centers on the recent advancements in plastic photoreforming, categorizing them based on the types of end products. Particular emphasis is placed on the evolving research landscape surrounding the conversion of plastics into high-value chemicals through photoreforming, as well as the economic considerations for large-scale photoreforming production. The analysis conducted here reveals key pathways and emerging trends that are poised to shape the trajectory of enhanced photoconversion, ultimately influencing the realization of a carbon-neutral future.

Upcycling of Polystyrene to Aromatic Polyacids by Tandem Friedel-Crafts and Oxidation Reactions

Due to the high demand and the increasing production rate of plastic materials, vast amounts of wastes are generated every year. An important fraction of these wastes contain polystyrene (PS), which is seldom recycled, neither mechanically nor chemically. While several chemical recycling strategies have been developed, they are either very energy-demanding or produce chemicals that can hardly be employed in the synthesis of plastics (e.g., benzene and benzoic acid). Here, we report the upcycling of PS waste into aromatic polyacids, useful in polyester synthesis, such as polyethylene terephthalate (PET). To this end, a conventional Friedel-Crafts acylation was first investigated, to produce an acylated PS chain, using acetic anhydride and stoichiometric amounts of AlCl3. As a catalytic alternative, the alkylation of PS was studied, using InCl3 and isopropyl acetate. The acylated and alkylated PS samples were then oxidized to produce terephthalic (TA), isophthalic (IPTA), benzoic (BA), and trimesic (TMA) acid.

Visible Light-Switchable Lattice Oxygen Sites for Selective C-H and C(O)-C Bond Electrooxidation

Lattice-oxygen is highly oxidizable, ideal for electrocatalytic C-H oxidation but insufficient alone for C(O)-C bond cleavage due to the non-removable nature of lattice sites. Here, we present a visible light-assisted electrochemical method of in situ formulating removable lattice-oxygen sites in a nickel-oxyhydroxide (ESE-NiOOH) electrocatalyst. This catalyst efficiently converts aromatic alcohols and carbonyls with C(O)-C fragments from lignin and plastics into benzoic acids (BAs) with high yields (83-99 %). Without light irradiation, ESE-NiOOH's intrinsic lattice-oxygen is non-removable and inert for C(O)-C bond cleavage. In situ characterizations show light-induced lattice-oxygen removal and regeneration via OH- refilling. Theoretical calculations identify the nucleophilic oxygen attack on ketone-derived carbanion as a rate-determining step, which can be remarkably facilitated by removable lattice-oxygen to activate α-C-H bonds. As a proof-of-concept, an "electrochemical funnel" strategy is developed for high-efficiency upgrading aromatic mixtures with C(O)-C moieties into BA with up to 94 % yield. This in situ removal-regeneration approach for lattice sites opens an avenue for the tailored design of interfacial electrocatalysts to selectively upcycle waste carbon sources into valuable products.

The current progress of tandem chemical and biological plastic upcycling

Each year, millions of tons of plastics are produced for use in such applications as packaging, construction, and textiles. While plastic is undeniably useful and convenient, its environmental fate and transport have raised growing concerns about waste and pollution. However, the ease and low cost of producing virgin plastic have so far made conventional plastic recycling economically unattractive. Common contaminants in plastic waste and shortcomings of the recycling processes themselves typically mean that recycled plastic products are of relatively low quality in some cases. The high cost and high energy requirements of typical recycling operations also reduce their economic benefits. In recent years, the bio-upcycling of chemically treated plastic waste has emerged as a promising alternative to conventional plastic recycling. Unlike recycling, bio-upcycling uses relatively mild process conditions to economically transform pretreated plastic waste into value-added products. In this review, we first provide a précis of the general methodology and limits of conventional plastic recycling. Then, we review recent advances in hybrid chemical/biological upcycling methods for different plastics, including polyethylene terephthalate, polyurethane, polyamide, polycarbonate, polyethylene, polypropylene, polystyrene, and polyvinyl chloride. For each kind of plastic, we summarize both the pretreatment methods for making the plastic bio-available and the microbial chassis for degrading or converting the treated plastic waste to value-added products. We also discuss both the limitations of upcycling processes for major plastics and their potential for bio-upcycling.

Asymmetric Membranes Obtained from Sulfonated HIPS Waste with Potential Application in Wastewater Treatment

The recovery and reuse of high-impact polystyrene (HIPS) into high-value products is crucial for reducing environmental thermoplastics waste and promoting sustainable materials for various applications. In this study, asymmetric membranes obtained from sulfonated HIPS waste were used for salt and dye removals. The incorporation of sulfonic acid (-SO3H) groups into HIPS waste by direct chemical sulfonation with chlorosulfonic acid (CSA), at two different concentrations, was investigated to impart antifouling properties in membranes for water treatment. Asymmetric membranes from recycled HIPS, R-HIPS, R-HIPS-3, and R-HIPS-5 with 3 and 5% sulfonation degrees, respectively. Sulfonated HIPS shows a decrease in water contact angle (WCA) from 83.8° for recycled R-HIPS to 66.1° for R-HIPS-5, respectively. A WCA decrease leads to an increase in antifouling properties for R-HIPS-5, compared to non-sulfonated R-HIPS, which leads to a higher flux recovery ratio (FRR) and enhanced separation properties for sulfonated membranes. The HIPS-5 membrane exhibited the highest rejection rates for Reactive Black 5 dye (94%) and divalent salts (72% for MgSO4 and 67% for Na2SO4). The performance of the recycled HIPS asymmetric membranes is well correlated with porosity, water uptake, and the higher negative charge from the sulfonic acid groups present, which enhance the electrostatic repulsions of salts and dyes.

Photocatalytic Upcycling of Different Types of Plastic Wastes: A Mini Review

With the escalating demand and utilization of plastics, considerable attention has been given to controlling plastic pollution. Among these methodologies, photocatalytic upcycling of plastic has emerged as a promising method for plastic management due to its energy-saving and eco-friendly properties. In the past several years, great efforts have been devoted to the photocatalytic conversion of a variety of commercial plastic types. These encouraging endeavors foreshadow the continued progression and application in this field. In this review, recent advancements in the photocatalytic upcycling of plastics are reviewed. The fundamentals and principles of photocatalytic deconstruction of plastics are first introduced. Then, we summarize the works on the reforming of different types of plastic, including polyolefins, polyesters, and other types. Finally, some challenges and possible solutions are provided for the development of photocatalytic upcycling of plastics.

Selective Upcycling of Polyolefins into High-Value Nitrogenated Chemicals

The selective upcycling of polyolefins to create products of increased value has emerged as an innovative approach to carbon resource stewardship, drawing significant scientific and industrial interest. Although recent advancements in recycling technology have facilitated the direct conversion of polyolefins to hydrocarbons or oxygenated compounds, the synthesis of nitrogenated compounds from such waste polyolefins has not yet been disclosed. Herein, we demonstrate a novel approach for the upcycling of waste polyolefins by efficiently transforming a range of postconsumer plastic products into nitriles and amides. This process leverages the catalytic properties of manganese dioxide in combination with an inexpensive nitrogen source, urea, to make it both practical and economically viable. Our approach not only opens new avenues for the creation of nitrogenated chemicals from polyolefin waste but also underscores the critical importance of recycling and valorizing carbon resources originally derived from fossil fuels. This study provides a new upcycling strategy for the sustainable conversion of waste polyolefins.

Photochemical Aerobic Upcycling of Polystyrene Plastics

Although the introduction of plastics has improved humanity's everyday life, the fast accumulation of plastic waste, including microplastics and nanoplastics, have created numerous problems with recent studies highlighting their involvement in various aspects of our lives. Upcycling of plastics, the conversion of plastic waste to high-added value chemicals, is a way to combat plastic waste that is receiving increased attention. Herein, we describe a novel aerobic photochemical process for the upcycling of real-life polystyrene-based plastics into benzoic acid. A new process employing a thioxanthone-derivative, in combination with N-bromosuccinimide, under ambient air and 390 nm irradiation is capable of upcycling real-life polystyrene-derived products in benzoic acid in yields varying from 24-54 %.

Controlled degradation of chemically stable poly(aryl ethers) via directing group-assisted catalysis

To establish a sustainable society, the development of polymer materials capable of reverting into monomers on demand is crucial. Traditional methods rely on breaking labile bonds such as esters in the main chain, which limits applicability to polymers that consist of robust covalent bonds. We found that the integration of directing groups allowed the engineering of resilient polymers with built-in recyclability. Our study showcases phenylene ether-based polymers fortified with directing groups, which can be selectively disassembled under nickel catalysts via selective cleavage of carbon-oxygen bonds. Notably, these polymers exhibit exceptional chemical stability towards acids, bases, and oxidizing agents, while being degradable to well-defined, repolymerizable molecules in the presence of a catalyst. Our findings allow for the development of next-generation polymer materials that are chemically recyclable by design.

A General Approach for Photo-Oxidative Degradation of Various Polymers

The escalating demand for plastics has resulted in a surge of plastic waste worldwide, posing a monumental environmental challenge. To address this issue, a versatile photo-oxidative degradation method applicable to seven distinct polymer families is proposed, comprising poly(isobutyl vinyl ether) (PIBVE), poly(2,3-dihydrofuran) (PDHF), poly(vinyl acetate) (PVAc), poly(n-butyl acrylate) (PBA), poly(methyl acrylate) (PMA), poly(vinyl chloride) (PVC), poly(dimethyl acrylamide) (PDMA), poly(ethylene oxide) (PEO), poly(oligo(ethylene glycol) methyl ether acrylate) (PEGMEA), and even poly(methyl methacrylate) (PMMA). This method employs photo-mediated hydrogen atom transfer (HAT) followed by oxidation to promote polymer degradation. This reaction is carried out under aerobic condition in the presence of iron trichloride (FeCl3) as a photocatalyst in combination with low-intensity purple light irradiation. The process can degrade up to 97% of the polymer in less than 3 h. This degradation process can be easily controlled by switching the light off, which allows for precise modulation of the degradation rate, enhancing the effectiveness of the method. Overall, this method provides a sustainable method for degrading various polymer types with low energy input.

Photophoretic MoS2-Fe2O3 Piranha Micromotors for Collective Dynamic Microplastics Removal

Microplastics are highly persistent emerging pollutants that are widely distributed in the environment. We report the use of MoS2@Fe2O3 core-shell micromotors prepared by a hydrothermal approach to explore the degradation of plastic microparticles. Polystyrene was chosen as the model plastic due to its wide distribution and resistance to degradation using current approaches. Micromotors show photophoretic-based motion at speeds of up to 6 mm s-1 and schooling behavior under full solar light spectra irradiation without the need for fuel or surfactants. During this impressive collective behavior, reactive oxygen species (ROS) are generated because of the semiconducting nature of the MoS2. Degradation of polystyrene beads is observed after 4 h irradiation because of the synergistic effect of ROS production and localized heat generation. The MoS2@Fe2O3 micromotors possess magnetic properties, which allow further cleaning and removal to be carried out after irradiation through magnetic pulling. The new micromotors hold considerable promise for full-scale treatment applications, only limited by our imagination.

Catalytic Upcycling of Polyolefins

The large production volumes of commodity polyolefins (specifically, polyethylene, polypropylene, polystyrene, and poly(vinyl chloride)), in conjunction with their low unit values and multitude of short-term uses, have resulted in a significant and pressing waste management challenge. Only a small fraction of these polyolefins is currently mechanically recycled, with the rest being incinerated, accumulating in landfills, or leaking into the natural environment. Since polyolefins are energy-rich materials, there is considerable interest in recouping some of their chemical value while simultaneously motivating more responsible end-of-life management. An emerging strategy is catalytic depolymerization, in which a portion of the C-C bonds in the polyolefin backbone is broken with the assistance of a catalyst and, in some cases, additional small molecule reagents. When the products are small molecules or materials with higher value in their own right, or as chemical feedstocks, the process is called upcycling. This review summarizes recent progress for four major catalytic upcycling strategies: hydrogenolysis, (hydro)cracking, tandem processes involving metathesis, and selective oxidation. Key considerations include macromolecular reaction mechanisms relative to small molecule mechanisms, catalyst design for macromolecular transformations, and the effect of process conditions on product selectivity. Metrics for describing polyolefin upcycling are critically evaluated, and an outlook for future advances is described.

Photocatalytic Cracking of non-Biodegradable Plastics to Chemicals and Fuels

Plastic pollution is worsening the living conditions on Earth, primarily due to the toxicity and stability of non-biodegradable plastics (NBPs). Photocatalytic cracking of NBPs is emerging as a promising way to cleave inert C-C bonds and abstract the carbon atoms from these wastes into valuable chemicals and fuels. However, controlling these processes is a huge challenge, ascribed to the complicated reactions of various NBPs. Herein, we summarize recent advances in the CO2 and carbon-radical-mediated photocatalytic cracking of NBPs, with an emphasis on the pivotal intermediates. The CO2-mediated cracking proceeded with indiscriminate C-H/C-C bond cleavage of NBPs and tandem photoreduction of CO2, while carbon-radical-mediated cracking was realized by the prior activation of C-H bonds for selective C-C bond cleavage of NBPs. Catalytic generation and conversion of different intermediates greatly depend on the kinds of active species and the structure of photocatalysts under irradiation. Meanwhile, the fate of a specific intermediate is compared with small molecule activation to reveal the key problems in the cracking of NBPs. Finally, the challenges and potential directions are discussed to improve the overall efficiency in the photocatalytic cracking of NBPs.

Industrial and Laboratory Technologies for the Chemical Recycling of Plastic Waste

Synthetic polymers play an indispensable role in modern society, finding applications across various sectors ranging from packaging, textiles, and consumer products to construction, electronics, and industrial machinery. Commodity plastics are cheap to produce, widely available, and versatile to meet diverse application needs. As a result, millions of metric tons of plastics are manufactured annually. However, current approaches for the chemical recycling of postconsumer plastic waste, primarily based on pyrolysis, lag in efficiency compared to their production methods. In recent years, significant research has focused on developing milder, economically viable methods for the chemical recycling of commodity plastics, which involves converting plastic waste back into monomers or transforming it into other valuable chemicals. This Perspective examines both industrial and cutting-edge laboratory-scale methods contributing to recent advancements in the field of chemical recycling.

Photochemical Aerobic Upcycling of Polystyrene Plastics via Synergistic Indirect HAT Catalysis

Plastic pollution constitutes an evergrowing urgent environmental problem, since overaccumulation of plastic waste, arising from the immense increase of the production of disposable plastic products, overcame planet's capacity to properly handle them. Chemical upcycling of polystyrene constitutes a convenient method for the conversion of plastic waste into high-added value chemicals, suggesting an attractive perspective in dealing with the environmental crisis. We demonstrate herein a novel, easy-to-perform organocatalytic photoinduced aerobic protocol, which proceeds via synergistic indirect hydrogen atom transfer (HAT) catalysis under LED 390 nm Kessil lamps as the irradiation source. The developed method employs a BrCH2CN-thioxanthone photocatalytic system and was successfully applied to a variety of everyday-life plastic products, leading to the isolation of benzoic acid after simple base-acid work up in yields varying from 23-49 %, while a large-scale experiment was successfully performed, suggesting that the photocatalytic step is susceptible to industrial application.

HOO• as the Chain Carrier for the Autocatalytic Photooxidation of Benzylic Alcohols

The oxidation of benzylic alcohols is an important transformation in modern organic synthesis. A plethora of photoredox protocols have been developed to achieve the aerobic oxidation of alcohols into carbonyls. Recently, several groups described that ultraviolet (UV) or purple light can initiate the aerobic oxidation of benzylic alcohols in the absence of an external catalyst, and depicted different mechanisms involving the photoinduction of •O2- as a critical reactive oxygen species (ROS). However, based on comprehensive mechanistic investigations, including control experiments, radical quenching experiments, EPR studies, UV-vis spectroscopy, kinetics studies, and density functional theory calculations (DFT), we elucidate here that HOO•, which is released via the H2O2 elimination of α-hydroxyl peroxyl radicals [ArCR(OH)OO•], serves as the real chain carrier for the autocatalytic photooxidation of benzylic alcohols. The mechanistic ambiguities depicted in the precedent literature are clarified, in terms of the crucial ROS and its evolution, the rate-limiting step, and the primary radical cascade. This work highlights the necessity of stricter mechanistic analyses on UV-driven oxidative reactions that involve aldehydes' (or ketones) generation.

Recent advances in oxidative degradation of plastics

Oxidative degradation is a powerful method to degrade plastics into oligomers and small oxidized products. While thermal energy has been conventionally employed as an external stimulus, recent advances in photochemistry have enabled photocatalytic oxidative degradation of polymers under mild conditions. This tutorial review presents an overview of oxidative degradation, from its earliest examples to emerging strategies. This review briefly discusses the motivation and the development of thermal oxidative degradation of polymers with a focus on underlying mechanisms. Then, we will examine modern studies primarily relevant to catalytic thermal oxidative degradation and photocatalytic oxidative degradation. Lastly, we highlight some unique studies using unconventional approaches for oxidative polymer degradation, such as electrochemistry.

Mechanically triggered on-demand degradation of polymers synthesized by radical polymerizations

Polymers that degrade on demand have the potential to facilitate chemical recycling, reduce environmental pollution and are useful in implant immolation, drug delivery or as adhesives that debond on demand. However, polymers made by radical polymerization, which feature all carbon-bond backbones and constitute the most important class of polymers, have proven difficult to render degradable. Here we report cyclobutene-based monomers that can be co-polymerized with conventional monomers and impart the resulting polymers with mechanically triggered degradability. The cyclobutene residues act as mechanophores and can undergo a mechanically triggered ring-opening reaction, which causes a rearrangement that renders the polymer chains cleavable by hydrolysis under basic conditions. These cyclobutene-based monomers are broadly applicable in free radical and controlled radical polymerizations, introduce functional groups into the backbone of polymers and allow the mechanically gated degradation of high-molecular-weight materials or cross-linked polymer networks into low-molecular-weight species.

Deconstruction of Polymers through Olefin Metathesis

The consumption of synthetic polymers has ballooned; so has the amount of post-consumer waste generated. The current polymer economy, however, is largely linear with most of the post-consumer waste being either landfilled or incinerated. The lack of recycling, together with the sizable carbon footprint of the polymer industry, has led to major negative environmental impacts. Over the past few years, chemical recycling technologies have gained significant traction as a possible technological route to tackle these challenges. In this regard, olefin metathesis, with its versatility and ease of operation, has emerged as an attractive tool. Here, we discuss the developments in olefin-metathesis-based chemical recycling technologies, including the development of new materials and the application of olefin metathesis to the recycling of commercial materials. We delve into structure-reactivity relationships in the context of polymerization-depolymerization behavior, how experimental conditions influence deconstruction outcomes, and the reaction pathways underlying these approaches. We also look at the current hurdles in adopting these technologies and relevant future directions for the field.

Recent Progresses and Challenges in Upcycling of Plastics through Selective Catalytic Oxidation

Chemical upcycling of plastics provides an important direction for solving the challenging issues of plastic pollution and mitigating the wastage of carbon resources. Among them, catalytic oxidative cracking of plastics to produce high-value chemicals, such as catalytic oxidation of polyethylene (PE) to produce fatty dicarboxylic acids, catalytic oxidation of polystyrene (PS) to produce benzoic acid, and catalytic oxidation of polyethylene terephthalate (PET) to produce terephthalic acid under mild conditions has attracted increasing attention, and some exciting progress has been made recently. In this article, we will review recent progresses on the catalytic oxidation upcycling of plastics and provide our understanding on the current challenges in catalytic oxidation upcycling of plastics.

Supramolecular metallic foams with ultrahigh specific strength and sustainable recyclability

Porous materials with ultrahigh specific strength are highly desirable for aerospace, automotive and construction applications. However, because of the harsh processing of metal foams and intrinsic low strength of polymer foams, both are difficult to meet the demand for scalable development of structural foams. Herein, we present a supramolecular metallic foam (SMF) enabled by core-shell nanostructured liquid metals connected with high-density metal-ligand coordination and hydrogen bonding interactions, which maintain fluid to avoid stress concentration during foam processing at subzero temperatures. The resulted SMFs exhibit ultrahigh specific strength of 489.68 kN m kg-1 (about 5 times and 56 times higher than aluminum foams and polyurethane foams) and specific modulus of 281.23 kN m kg-1 to withstand the repeated loading of a car, overturning the previous understanding of the difficulty to achieve ultrahigh mechanical properties in traditional polymeric or organic foams. More importantly, end-of-life SMFs can be reprocessed into value-added products (e.g., fibers and films) by facile water reprocessing due to the high-density interfacial supramolecular bonding. We envisage this work will not only pave the way for porous structural materials design but also show the sustainable solution to plastic environmental risks.

Chemically Recyclable, High Molar Mass Polyoxazolidinones via Ring-Opening Metathesis Polymerization

The development of robust methods for the synthesis of chemically recyclable polymers with tunable properties is necessary for the design of next-generation materials. Polyoxazolidinones (POxa), polymers with five-membered urethanes in their backbones, are an attractive target because they are strongly polar and have high thermal stability, but existing step-growth syntheses limit molar masses and methods to chemically recycle POxa to monomer are rare. Herein, we report the synthesis of high molar mass POxa via ring-opening metathesis polymerization of oxazolidinone-fused cyclooctenes. These novel polymers show <5% mass loss up to 382-411 °C and have tunable glass transition temperatures (14-48 °C) controlled by the side chain structure. We demonstrate facile chemical recycling to monomer and repolymerization despite moderately high monomer ring-strain energies, which we hypothesize are facilitated by the conformational restriction introduced by the fused oxazolidinone ring. This method represents the first chain growth synthesis of POxa and provides a versatile platform for the study and application of this emerging subclass of polyurethanes.

Photocatalytic Upcycling and Depolymerization of Vinyl Polymers

Photocatalytic upcycling and depolymerization of vinyl polymers have emerged as promising strategies to combat plastic pollution and promote a circular economy. This mini review critically summarizes current developments in the upcycling and degradation of vinyl polymers including polystyrene and poly(meth)acrylates. Of these material classes, polymethacrylates possess the unique possibility to undergo a photocatalytic depolymerization back to monomer under thermodynamically favourable conditions, thus presenting significant advantages over traditional thermal strategies. Our perspective on current formidable challenges and potential future directions are also discussed.

Cu-Catalyzed Coupling of Aliphatic Amines with Alkylboronic Esters

We report a Cu-catalyzed oxidative coupling of aliphatic amines with benzylic and aliphatic boronic esters to give high value alkyl amines, products found widely in applications from medicinal chemistry to materials science. This operationally simple reaction, which can be performed on gram scale, runs under mild conditions and exhibits broad functional group tolerance. The terminal oxidant of the reaction is O2 from the air, avoiding the need for additional chemical oxidants. Investigation into the reaction mechanism suggests that the boronic ester is activated by an aminyl radical, formed through oxidation of the amine by the Cu catalyst, to give a key alkyl radical intermediate. To demonstrate its utility and potential for late-stage functionalization, we showcase the method as the final step in the total synthesis of a TRPV1 antagonist.

Light-driven polymer recycling to monomers and small molecules

Only a small proportion of global plastic waste is recycled, of which most is mechanically recycled into lower quality materials. The alternative, chemical recycling, enables renewed production of pristine materials, but generally comes at a high energy cost, particularly for processes like pyrolysis. This review focuses on light-driven approaches for chemically recycling and upcycling plastic waste, with emphasis on reduced energy consumption and selective transformations not achievable with heat-driven methods. We focus on challenging to recycle backbone structures composed of mainly C‒C bonds, which lack functional groups i.e., esters or amides, that facilitate chemical recycling e.g., by solvolysis. We discuss the use of light, either in conjunction with heat to drive depolymerization to monomers or via photocatalysis to transform polymers into valuable small molecules. The structural prerequisites for these approaches are outlined, highlighting their advantages as well as limitations. We conclude with an outlook, addressing key challenges, opportunities, and provide guidelines for future photocatalyst (PC) development.

Upcycling Waste Plastics with a C-C Backbone by Heterogeneous Catalysis

Plastics with an inert carbon-carbon (C-C) backbone, such as polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC), are the most widely used types of plastic in human activities. However, many of these polymers were directly discarded in nature after use, and few were appropriately recycled. This not only threatens the natural environment but also leads to the waste of carbon resources. Conventional chemical recycling of these plastics, including pyrolysis and catalytic cracking, requires a high energy input due to the chemical inertness of C-C bonds and C-H bonds and leads to complex product distribution. In recent years, significant progress has been made in the development of catalysts and the introduction of small molecules as additional coreactants, which could potentially overcome these challenges. In this Review, we summarize and highlight catalytic strategies that address these issues in upcycling C-C backbone plastics with small molecules, particularly in heterogeneous catalysis. We believe that this review will inspire the development of upcycling methods for C-C backbone plastics using small molecules and heterogeneous catalysis.

Catalytic conversion of mixed polyolefins under mild atmospheric pressure

The chemical recycling of polyolefin presents a considerable challenge, especially as upcycling methods struggle with the reality that plastic wastes typically consist of mixtures of polyethylene (PE), polystyrene (PS), and polypropylene (PP). We report a catalytic aerobic oxidative approach for polyolefins upcycling with the corresponding carboxylic acids as the product. This method encompasses three key innovations. First, it operates under atmospheric pressure and mild conditions, using O2 or air as the oxidant. Second, it is compatible with high-density polyethylene, low-density polyethylene, PS, PP, and their blends. Third, it uses an economical and recoverable metal catalyst. It has been demonstrated that this approach can efficiently degrade mixed wastes of plastic bags, bottles, masks, and foam boxes.

Robust links in photoactive covalent organic frameworks enable effective photocatalytic reactions under harsh conditions

Developing heterogeneous photocatalysts for the applications in harsh conditions is of high importance but challenging. Herein, by converting the imine linkages into quinoline groups of triphenylamine incorporated covalent organic frameworks (COFs), two photosensitive COFs, namely TFPA-TAPT-COF-Q and TFPA-TPB-COF-Q, are successfully constructed. The obtained quinoline-linked COFs display improved stability and photocatalytic activity, making them suitable photocatalysts for photocatalytic reactions under harsh conditions, as verified by the recyclable photocatalytic reactions of organic acid involving oxidative decarboxylation and organic base involving benzylamine coupling. Under strong oxidative condition, the quinoline-linked COFs show a high efficiency up to 11831.6 μmol·g-1·h-1 and a long-term recyclable usability for photocatalytic production of H2O2, while the pristine imine-linked COFs are less catalytically active and easily decomposed in these harsh conditions. The results demonstrate that enhancing the linkage robustness of photoactive COFs is a promising strategy to construct heterogeneous catalysts for photocatalytic reactions under harsh conditions.

Indirect daylight oxidative degradation of polyethylene microplastics by a bio-waste modified TiO2-based material

Microplastics are recognized as an emerging critical issue for the environment. Here an innovative chemical approach for the treatment of microplastics is proposed, based on an oxidative process that does not require any direct energy source (irradiation or heat). Linear low-density polyethylene (LLDPE) was selected as target commodity polymer, due to its widespread use, chemical inertness and inefficient recycling. This route is based on a hybrid material coupling titanium oxide with a bio-waste, rosin, mainly constituted by abietic acid, through a simple sol-gel synthesis procedure. The ligand-to-metal charge transfer complexes formed between rosin and Ti4+ allow the generation of reactive oxygen species without UV irradiation for its activation. In agreement with theorical calculations, superoxide radical ions are stabilized at ambient conditions on the surface of the hybrid TiO2. Consequently, an impressive degradation of LLDPE is observed after 1 month exposure in a batch configuration under indirect daylight, as evidenced by the products revealed by gas chromatography-mass spectrometry analysis and by chemical and structural modifications of the polymer surface. In a context of waste exploitation, this innovative and sustainable approach represents a promising cost-effective strategy for the oxidative degradation of microplastics, without producing any toxic by-products.

Innovations in chemical degradation technologies for the removal of micro/nano-plastics in water: A comprehensive review

Micro/nanoplastics (M/NPs) in water have raised global concern due to their potential environmental risks. To reestablish a M/NPs free world, enormous attempts have been made toward employing chemical technologies for their removal in water. This review comprehensively summarizes the advances in chemical degradation approaches for M/NPs elimination. It details and discusses promising techniques, including photo-based technologies, Fenton-based reaction, electrochemical oxidation, and novel micro/nanomotors approaches. Subsequently, critical influence factors, such as properties of M/NPs and operating factors, are analyzed in this review specifically. Finally, it concludes by addressing the current challenges and future perspectives in chemical degradation. This review will provide guidance for scientists to further explore novel strategies and develop feasible chemical methods for the improved control and remediation of M/NPs in the future.

Selective poly(vinyl ether) upcycling via photooxidative degradation with visible light

Poly(vinyl ethers) (PVEs) have many applications, such as adhesives, lubricants, and anticorrosive agents, thanks to their elastic, nonirritating, and chemically inert properties. The recycling of PVEs remains largely underexplored, and current methods lack generality towards other polymer classes. Thus, the chemical upcycling of PVE into small molecule feedstocks would provide an alternative approach to combat these current issues. Here, we report a visible light-mediated method of upcycling poly(isobutyl vinyl ether) (PIBVE) into small molecules via photooxidative degradation using chlorine or bromine radicals. PIBVE can be degraded to low molecular weight oligomers within 2 h, producing good yields of alcohols, aldehydes, and carboxylic acids. Mechanistic studies suggest that hydrogen atom transfer (HAT) from the backbone or the side chain leads to small molecule generation via oxidative cleavages. Additionally, this protocol was applied to a copolymer of poly(methyl acrylate-co-isobutyl vinyl ether) to demonstrate the preference for the degradation of polymers bearing more electron-rich C-H bonds through a judicious choice of abstraction agent. Ultimately, we show that photooxidative degradation enables the selective chemical upcycling of PVEs as a method of plastic waste valorization.