Untangling the chemical complexity of plastics to improve life cycle outcomes.

A diversity of chemicals are intentionally added to plastics to enhance their properties and aid in manufacture. Yet, the accumulated chemical composition of these materials is essentially unknown even to those within the supply chain, let alone to consumers or recyclers. Recent legislated and voluntary commitments to increase recycled content in plastic products highlight the practical challenges wrought by these chemical mixtures, amid growing public concern about the impacts of plastic-associated chemicals on environmental and human health.

Polymeric bis(triphenylphosphine)iminium chloride as a recyclable catalyst.

Metal-free catalysts have garnered considerable interest as an environmental and economical alternative to precious metal catalysts. Bis(triphenylphosphine)iminium chloride (PPNCl) has emerged as a prominent choice due to its air and thermal stability and broad reactivity, especially in applications where a bulky cation is needed. The high phosphorus content and synthetic effort required for catalyst synthesis increase environmental impact; the recyclability of PPNCl in catalytic processes remains largely unexplored.

Mechanical Properties and Recyclability of Fiber Reinforced Polyester Composites.

Fiber reinforced polymer composites (FRPs) are valuable construction materials owing to their strength, durability, and design flexibility; however, conventional FRPs utilize petroleum-based polymer matrices with limited recyclability. Furthermore, fiber reinforcements are made from nonrenewable feedstocks, through expensive and energy intensive processes, making recovery and reuse advantageous. Thus, FRPs that use biobased and degradable or reprocessable matrices would enable a more sustainable product, as both components can be recovered and reused.

Depolymerization within a Circular Plastics System.

The societal importance of plastics contrasts with the carelessness with which they are disposed. Their superlative properties lead to economic and environmental efficiency, but the linearity of plastics puts the climate, human health, and global ecosystems at risk. Recycling is fundamental to transitioning this linear model into a more sustainable, circular economy.

Sustainable formulation polymers for home, beauty and personal care: challenges and opportunities.

As society moves towards a net-zero future, the need to adopt more sustainable polymers is well understood, and as well as plastics, less visible formulation polymers should also be included within this shift. As researchers, industries and consumers move towards more sustainable products there is a clear need to define what sustainability means in fast moving consumer goods and how it can be considered at the design stage. In this perspective key challenges in achieving sustainable formulation polymers are highlighted, and opportunities to overcome them are presented.

Light-Induced Polymeric Frustrated Radical Pairs as Building Blocks for Materials and Photocatalysts.

Polymeric frustrated Lewis pairs, or poly(FLP)s, have served to bridge the gap between functional polymer science and main group catalysis, pairing the uniqueness of sterically frustrated Lewis acids and bases with a polymer scaffold to create self-healing gels and recyclable catalysts. However, their utilization in radical chemistry is unprecedented. In this paper, we disclose the synthesis of polymeric frustrated radical pairs, or poly(FRP)s, by in situ photoinduction of FLP moieties, where their Lewis acidic and basic centers are tuned to promote single electron transfer (SET).

Circularizing PET-G Multimaterials: Life Cycle Assessment and Techno-Economic Analysis.

The recycling of multimaterials such as payment or access cards poses significant challenges. Building on previous experimental work demonstrating the feasibility of chemically recyclable payment cards made from glycol-modified poly(ethylene terephthalate) (PET-G), we use life cycle assessment and techno-economic analysis to investigate two chemical recycling scenarios and evaluate their potential environmental and economic benefits. Recovering all components from the depolymerized products (Scenario 1) achieves substantial environmental benefits across most categories, reducing global warming by up to 67% compared to only recovering major components (Scenario 2).

Biodegradable and conventional plastic packaging: Comparison of life cycle environmental impacts of poly(mandelic acid) and polystyrene.

Most of plastic packaging waste does not degrade over time, which can lead to harmful effects on aquatic life and humans, highlighting the need for packaging materials that are easily degradable. Poly(mandelic acid) (PMA) is a biodegradable polymer that has been proposed as an alternative to polystyrene for use in packaging. However, its potential to replace the existing packaging materials also depends, among other factors, on the environmental sustainability of its production.

Degradable and Reprocessable Resins from a Dioxolanone Cross-Linker.

Chemically cross-linked polymers offer excellent temperature and solvent resistance, but their high dimensional stability precludes reprocessing. The renewed demand for sustainable and circular polymers from public, industry, and government stakeholders has increased research into recycling thermoplastics, but thermosets have often been overlooked. To address this need for more sustainable thermosets, we have developed a novel bis(1,3-dioxolan-4-one) monomer, derived from the naturally occurring l-(+)-tartaric acid.

Recycled Plastic Content Quantified through Aggregation-Induced Emission.

The linearity of the plastics economy is wasteful and polluting. To encourage recycling and decrease diversion to landfill, new legislation within the EU and UK will tax single-use plastic products made with less than 30% recycled plastic. At present, quantitative determination of recycled content is elusive and existing methods are inconsistent.

Sustainability and Polyesters: Beyond Metals and Monomers to Function and Fate.

Poor waste management and unchecked consumption underpin our current paradigm of plastics use, which is demonstrably unsustainable in the long term. Nonetheless, the utility and versatility of plastics suggest that the notion of a plastic-free society is also unsustainable. Responses to this conundrum are increasing, and among these are research efforts focused on the development of more sustainable plastics.

Low Formaldehyde Binders for Mineral Wool Insulation: A Review.

Insulating materials are ubiquitous in a built environment and play a critical role in reducing the energy consumed to maintain habitable indoor environments. Mineral wool insulation (MWI) products, including glass, stone, and slag variants, are the most widely used class of insulating materials in Europe and account for more than 50% of the total market by volume. MWI typically consists of two key components: a mesh of inorganic fibers that are several micrometers in diameter, and an organic thermosetting adhesive commonly referred to as the "binder.

Polymeric frustrated Lewis pairs in CO/cyclic ether coupling catalysis.

Frustrated Lewis pairs (FLPs) are now ubiquitous as metal-free catalysts in an array of different chemical transformations. In this paper we show that this reactivity can be transferred to a polymeric system, offering advantageous opportunities at the interface between catalysis and stimuli-responsive materials. Formation of cyclic carbonates from cyclic ethers using CO as a C feedstock continues to be dominated by metal-based systems.

Cyclic Ether Triggers for Polymeric Frustrated Lewis Pair Gels.

Sterically hindered Lewis acid and base centers are unable to form Lewis adducts, instead forming frustrated Lewis pairs (FLPs), where latent reactivity can be utilized for the activation of small molecules. Applying FLP chemistry into polymeric frameworks transforms this chemistry into responsive and functional materials. Here, we report a versatile synthesis strategy for the preparation of macromolecular FLPs and explore its potential with the ring-opening reactions of cyclic ethers.

Combining alkali metals and zinc to harness heterometallic cooperativity in cyclic ester ring-opening polymerisation.

Heterometallic cooperativity is an emerging strategy to elevate polymerisation catalyst performance. Here, we report the first heterotrimetallic Na/Zn and K/Zn complexes supported by a ProPhenol ligand, which deliver "best of both" in cyclic ester ring-opening polymerisation, combining the outstanding activity (Na/K) and good control (Zn) of homometallic analogues. Detailed NMR studies and density-functional theory calculations suggest that the Na/Zn and K/Zn complexes retain their heterometallic structures in the solution-state.

Mechanical Recycling of Packaging Plastics: A Review.

The current global plastics economy is highly linear, with the exceptional performance and low carbon footprint of polymeric materials at odds with dramatic increases in plastic waste. Transitioning to a circular economy that retains plastic in its highest value condition is essential to reduce environmental impacts, promoting reduction, reuse, and recycling. Mechanical recycling is an essential tool in an environmentally and economically sustainable economy of plastics, but current mechanical recycling processes are limited by cost, degradation of mechanical properties, and inconsistent quality products.

Iron Half Salen Catalysts for Atom Transfer Radical and Ring-Opening Polymerizations.

A series of monometallic pentacoordinate Fe chloride complexes have been prepared and characterized by high-resolution mass spectrometry and elemental analysis. X-ray diffraction analysis showed that the bis-chelated Fe complexes bear distorted trigonal bipyramidal geometries. The air- and moisture-stable Fe complexes were screened as mediators in the reverse atom transfer radical polymerization (ATRP) of styrene and methyl methacrylate.

Alkyne-Tagged PLGA Allows Direct Visualization of Nanoparticles In Vitro and Ex Vivo by Stimulated Raman Scattering Microscopy.

Polymeric nanoparticles (NPs) are attractive candidates for the controlled and targeted delivery of therapeutics in vitro and in vivo. However, detailed understanding of the uptake, location, and ultimate cellular fate of the NPs is necessary to satisfy safety concerns, which is difficult because of the nanoscale size of these carriers. In this work, we show how small chemical labels can be appended to poly(lactic acid--glycolic acid) (PLGA) to synthesize NPs that can then be imaged by stimulated Raman scattering microscopy, a vibrational imaging technique that can elucidate bond-specific information in biological environments, such as the identification of alkyne signatures in modified PLGA terpolymers.

Morpholino Oligonucleotide Cross-Linked Hydrogels as Portable Optical Oligonucleotide Biosensors.

Morpholino Oligonucleotides (MOs), an uncharged DNA analogue, are functionalized with an acrylamide moiety and incorporated into polymer hydrogels as responsive cross-links for microRNA sequence detection. The MO cross-links can be selectively cleaved by a short target analyte single-stranded DNA (ssDNA) sequence based on microRNA, inducing a distinct swelling response measured optically. The MO cross-links offer significant improvement over DNA based systems through improved thermal stability, no salt requirement and 1000-fold improved sensitivity over a comparative biosensor, facilitating a wider range of sensing conditions.

Correction: Polymeric hole-transport materials with side-chain redox-active groups for perovskite solar cells with good reproducibility.

Correction for 'Polymeric hole-transport materials with side-chain redox-active groups for perovskite solar cells with good reproducibility' by Rosinda Fuentes Pineda et al., Phys. Chem.

Polymeric hole-transport materials with side-chain redox-active groups for perovskite solar cells with good reproducibility.

Two monomers, M:OO and M:ON, and their corresponding polymers, P:OO and P:ON, were prepared from styrene derivatives N,N-diphenyl-4-vinyl-aniline with different substituents (-OCH3 and -N(CH3)2) in the N-phenyl para positions. The polymers were synthesised and fully characterised to study their function as hole transport materials (HTMs) in perovskite solar cells (PSCs). The thermal, optical and electrochemical properties and performance of these monomers and polymers as HTMs in PSCs were compared in terms of their structure.

Stable Fe(iii) phenoxyimines as selective and robust CO/epoxide coupling catalysts.

Three phenoxyimine Fe(iii)Cl complexes bearing electronically diverse -Cl, -H or -Bu substituents in the ortho position were synthesised. X-ray crystallographic analysis of the complexes reveals mononuclear structures with pentacoordinate iron centres and trigonal bipyramidal geometries. All three complexes demonstrated excellent catalytic activities towards CO/epoxide coupling to selectively form cyclic carbonates, with catalyst activity correlating with the electron withdrawing nature of the ortho-substituent (Cl > H > Bu) and thus the Lewis acidity of the metal centre.