Progress in Polymer Science最新文献

As an abundant, renewable, and inexpensive carbon feedstock, CO₂ can be converted into valuable products, creating substantial environmental and economic benefits. Polyurethanes (PUs) and polyureas (PUAs) with versatile properties have been commonly used in everyday life applications and possess vast market demand. CO₂-sourced PUs and PUAs can alleviate the involvement of petroleum, and they have attracted ever-increasing attention from industry and academia because of their high economic value and fancy properties in many high-value-added material fields. This has led to their recognition as a promising strategy from the viewpoint of green and sustainable chemistry. In this review, the state-of-the-art research progress on CO₂-based PUs and PUAs, with particular emphasis on their synthetic principles, modifications, applications, and degradability are summarized. Additionally, future considerations, prospects, and possible challenges in converting CO₂ to nitrogenous polymers are also discussed. This review is intended to serve as a tutorial guide for the future development of novel CO₂-sourced PUs and PUAs with unique properties and functions.

This review presents a comprehensive description of the current pathways used in the chemical recycling of oxygenated plastics, with a specific focus on poly(ethylene terephthalate) (PET), poly(bisphenol-A carbonate) (PC), and polyethers including anhydride-cured epoxies. For PC and PET, the emphasis is on processes that achieve high depolymerization efficiencies as well as monomer selectivity and the potential to simplify downstream processing for the recovery of pure monomers. In the case of epoxies, this work focuses on depolymerization processes that produce curable molecules, as studies on epoxy depolymerization are scarce. To assess scalability, different depolymerization pathways are compared for each polymer based on the process conditions and monomer yields. The review concludes with the discussion on potentials and challenges of the distinct depolymerization pathways that have been developed for oxygenated plastics, such as hydrolysis, alcoholysis, and reductive depolymerization.

Plastics are nowadays essential to our daily life for a wide range of applications. In order to face the demand of polymer markets, given the depletion of fossil feedstocks from which they are still most commonly produced, and with the aim to develop more ecofriendly plastic materials, the need for renewable and/or recyclable polymers is huge. Polyhydroxyalkanoates (PHAs) are a class of polyesters that could meet the challenges of such a circular economy, as they currently stand as promising bio-based, degradable and recyclable alternatives to traditional non-degradable commodity polymers that are polyolefins. PHAs typically feature different side-chain substituents on the repeating units, which beside the stereochemistry along the polymer backbone and the intrinsic characteristics of the macromolecules, are key parameters that dictate and enable tuning of their thermal, mechanical, and recyclability performances. PHAs are thus a large family of versatile polymers that are currently of topical interest in light of their end-of-life options. This review discusses the chemical recycling of natural, biosynthetic and synthetic PHAs, mainly focusing on the most common examples, namely poly(3-hydroxybutyrate) (PHB), and its related copolymers. The most relevant non-biotechnological approaches, including pyrolysis-type processes, and solvolysis with especially hydrolysis and alcoholysis, whether they are catalyzed or not, are then addressed. The latest advances on the degradation, depolymerization and upcycling of PHAs, show promising outcomes for a close-carbon cycle economy with a favorable environmental impact, as exemplified from the most recent literature.

Molecular solar thermal (MOST) fuels have attracted enormous research enthusiasm in solar energy conversion and storage, which can generate high-energy isomers upon harvesting photon energy and release heat on demand through reversible isomerization of molecular photo-switches such as azobenzene. However, the pristine azobenzene suffers from limitations like low energy density, short half-life and narrow absorption waveband. Recently, numerous azobenzene-based MOST fuels have been developed by various strategies including molecular engineering and template self-assembly to enhance the storage capacities, among which azobenzene-containing polymers (i.e., ‘azopolymers’) are the most promising materials for the development of MOST fuels. In this review, the state-of-the-art advances in azopolymer MOST fuels are systematically summarized. The critical parameters of azobenzene-based MOST fuels are highlighted. Various kinds of azopolymers for solar thermal energy storage and release such as azobenzene compound/polymer composites, linear azopolymers, dendrimer azopolymers, and other types of azopolymers are addressed. The most promising advantages and challenges of azopolymers for MOST fuels are analyzed, and emerging strategies as well as opportunities for future development are discussed with the goal to promote future development of MOST fuels towards innovative applications.

Flexible electronic devices offer new appealing possibilities expanding and revolutionizing the field of energy, consumer electronics, communication, health, and more. Many of these technologies rely on transparent electrodes which are typically fabricated by Indium Tin Oxide (ITO) but there is an urgent need to find more sustainable and low-cost alternatives. While significant progress has been made, there are still challenges to overcome for the fabrication of efficient Transparent Electrodes (TEs). Conducting polymers offer a promising solution for printable TEs, combining conductivity (σ) and transparency with the benefits of abundance, lightweight, and flexibility. This Trend Article examines various material categories being studied for developing transparent electrodes, including metal oxides, metals, and carbon nanostructures. The potential of conducting polymers is highlighted, along with the solution-based coating and printing technologies rising with them, to adapt to the intricate and emerging requirements of our modern world.

The self-assembly of low-molecular-weight building motifs into supramolecular polymers has unlocked a new realm of materials with distinct properties and tremendous potential for advancing medical practices. Leveraging the reversible and dynamic nature of non-covalent interactions, these supramolecular polymers exhibit inherent responsiveness to their microenvironment, physiological cues, and biomolecular signals, making them uniquely suited for diverse biomedical applications. In this review, we intend to explore the principles of design, synthesis methodologies, and strategic developments that underlie the creation of supramolecular polymers as carriers for therapeutics, contributing to the treatment and prevention of a spectrum of human diseases. We delve into the principles underlying monomer design, emphasizing the pivotal role of non-covalent interactions, directionality, and reversibility. Moreover, we explore the intricate balance between thermodynamics and kinetics in supramolecular polymerization, illuminating strategies for achieving controlled sizes and distributions. Categorically, we examine their exciting biomedical applications: individual polymers as discrete carriers for therapeutics, delving into their interactions with cells, and in vivo dynamics; and supramolecular polymeric hydrogels as injectable depots, with a focus on their roles in cancer immunotherapy, sustained drug release, and regenerative medicine. As the field continues to burgeon, harnessing the unique attributes of therapeutic supramolecular polymers holds the promise of transformative impacts across the biomedical landscape.

Polymers have many advantages such as low weight, low cost, and, importantly, stability under thermal, chemical, and mechanical stress. This stability, on the other hand, leads to criticism for causing environmental pollution on a macro-scale and via long-lasting microscopic plastic fragments (microplastics). Since it is very difficult but also very expensive to design brand-new materials that could both have the desired properties (mechanical, thermal, solvent resistance, etc.) and that are in the same time either recyclable and/or biodegradable, transforming already known materials to make them biodegradable/recyclable is more interesting. This approach relies on the introduction of labile/cleavable bonds onto the polymer backbone. The degradation could thus occur from these weak bonds leading to oligomers that could be easily recyclable and/or bioassimilable. This approach is currently applied to all polymerization techniques and led to interesting alternatives to numerous polymers ranging from polyolefins (polyethylene, polypropylene, …), polyethylene oxide, polyesters, polyamides, vinyl polymers, thermosets, etc. This review thus aimed at giving a comprehensive overview of the chemistries/monomers that could be used for the different polymerization processes but also described the alternatives to common polymers whatever the polymerization process. An emphasis will be put on the degradation/biodegradation/recycling properties of the new materials.

Bottom-up synthesis strategies to construct nano-architectonic material exhibiting specific properties by controlling the spatial distribution of the material units are challenging. Native polysaccharide nanocrystals, primarily cellulose and chitin nanocrystals (CNCs and ChNCs), possess excellent intrinsic biodegradability, biocompatibility, tailorable surface chemistry, and unprecedented optical and mechanical properties. These nanocrystals, in particular CNCs, have attracted considerable attention within the last years for constructing optical materials via bottom-up self-assembly. Here, the physicochemical mechanisms underlying the self-assembly of CNC nanocrystals and the structure-property relations of CNC nanocrystal assembly structures are summarized, including the transition from the isotropic phase at low concentrations to the cholesteric phase at high concentrations, and finally to dry films in a fixed state. The properties of aggregated and self-assembled CNCs are described in detail. Based on the dimensions of self-assembled structures as divided in zero-, one, two and three-dimensional constructions, recent advances of polysaccharide nanocrystals-based optical materials are discussed. Finally, the challenges of the methods for the environmentally benign preparation of polysaccharide nanocrystals are identified and the opportunities for realizing novel functional materials based on polysaccharide nanocrystal assembly are described.

Synthetic biodegradable elastomers, such as polyesters and polyurethanes have revolutionized biomedical therapeutic strategies and devices. Driven by innovations in chemical synthesis and processing technologies, a series of biodegradable elastomers and corresponding devices with controllable properties and various functionalities have been developed. In this review, we have summarized the recent progress in synthesis, process technologies, and biomedical applications of biodegradable elastomers. Particular emphasis is on the molecular design for biodegradability, elasticity, and the newly developed functionalities including self-healing, antibacterial, fluorescence, and shape-memory of biodegradable polyesters and polyurethane as well as their corresponding processing strategies. Subsequently, the recent progress of biodegradable elastomers in different biomedical applications is reviewed. A comprehensive conclusion and outlook pointing out emerging research directions, future challenges and potential solutions complete this work.

With the growing demand for clinically reliable therapeutics, traditional small molecule drugs are increasingly limited by their short circulation duration, low bioavailability, and poor targeting. Protein drugs, on the other hand, have gained popularity due to their high activity, high specificity, low cytotoxicity, and distinct biological function. Especially, monoclonal antibodies are among the top 10 drugs in global sales. However, protein drugs have limitations such as complex and unstable structure, immune clearance caused by antigen fragments on the surface, and inability to penetrate cell membranes, which severely restrict intracellular delivery. Using carriers can greatly enhance the stability of protein drugs, prevent immune clearance, and facilitate their cellular uptake and cytosolic release. Polymers are commonly used for delivering small molecules, DNA, and RNA. However, developing polymers for protein delivery with high efficiency and low cytotoxicity still faces several challenges, including poor protein binding ability, membrane impermeability, and low endo/lysosomal escape efficiency. Functionalizing polymers with specific components such as fluorine, boron, guanidine, heterocycles, and multicomponents can improve polymer-protein interaction, cell membrane penetration, endo/lysosomal escape, and biocompatibility. This review provides an overview of strategies for polymer functionalization and their effects on protein delivery. It also discusses trends and challenges in developing polymer carriers for protein delivery.