Explore the vast range of titles available.

HighlightsGraphene oxide-based hybrid networks were fabricated via introducing multi-amino molecule with triple roles (i.e., cross-linker, fire retardant and reducing agent).The optimized hybrid network with mechanically robust, exceptional intumescent effect and ultra-sensitive fire alarm response (~ 0.6 s) can be used as desirable smart fire alarm sensor materials.Exceptional fire shielding performances, e.g., ~ 60% reduction in peak heat release rate and limiting oxygen index of ~ 36.5%, are achieved, when coated such hybrid network onto combustible polymer foam.Smart fire alarm sensor (FAS) materials with mechanically robust, excellent flame retardancy as well as ultra-sensitive temperature-responsive capability are highly attractive platforms for fire safety application. However, most reported FAS materials can hardly provide sensitive, continuous and reliable alarm signal output due to their undesirable temperature-responsive, flame-resistant and mechanical performances. To overcome these hurdles, herein, we utilize the multi-amino molecule, named HCPA, that can serve as triple-roles including cross-linker, fire retardant and reducing agent for decorating graphene oxide (GO) sheets and obtaining the GO/HCPA hybrid networks. Benefiting from the formation of multi-interactions in hybrid network, the optimized GO/HCPA network exhibits significant increment in mechanical strength, e.g., tensile strength and toughness increase of ~ 2.3 and ~ 5.7 times, respectively, compared to the control one. More importantly, based on P and N doping and promoting thermal reduction effect on GO network, the excellent flame retardancy (withstanding ~ 1200 °C flame attack), ultra-fast fire alarm response time (~ 0.6 s) and ultra-long alarming period (> 600 s) are obtained, representing the best comprehensive performance of GO-based FAS counterparts. Furthermore, based on GO/HCPA network, the fireproof coating is constructed and applied in polymer foam and exhibited exceptional fire shielding performance. This work provides a new idea for designing and fabricating desirable FAS materials and fireproof coatings.

Polymeric materials are ubiquitously utilized in modern society and continuously improve quality of life. Unfortunately, most of them suffer from intrinsic flammability, significantly limiting their practical applications. Fundamentally, free‐radical reaction is a critical “trigger” for their thermal pyrolysis and following combustion process regardless of the anaerobic thermal pyrolysis in the condensed phase or aerobic combustion of polymers in the gaseous phase. The addition of free radical scavengers represents a promising and effective means to enhance the fire safety of polymeric materials. This review aims to offer a state‐of‐the‐art overview on the creation of fire‐retardant polymeric nanocomposites by adding fire retardants with an ability to trap free radicals. Their specific modes of action (condensed‐phase action, gaseous‐phase action, and dual‐phases action) and performances in some typical polymers are reviewed and discussed in detail. Following this, some key challenges associated with these free‐radical capturers are discussed, and design strategies are also proposed. This review provides some insights into the modes of action of free radical capturing agents and paves the avenue for the design of advanced fire‐retardant polymeric nanocomposites for expanded real‐world applications in industries. This work provides a state‐of‐the‐art overview on the creation of fire‐retardant polymeric nanocomposites by adding free radical fighters. The action of modes and performances of these free radical fighters in some of typical polymer matrices are reviewed. The key challenges associated with these free radical scavengers are discussed, followed by some proposed strategies. This review is expected to pave a new avenue for the design of advanced fire‐retardant polymeric nanocomposites which help to create a sustainable and fireresilient world.

Advanced elastomers are increasingly used in emerging areas, for example, flexible electronics and devices, and these real‐world applications often require elastomers to be stretchable, tough and fire safe. However, to date there are few successes in achieving such a performance portfolio due to their different governing mechanisms. Herein, a stretchable, supertough, and self‐extinguishing polyurethane elastomers by introducing dynamic π–π stacking motifs and phosphorus‐containing moieties are reported. The resultant elastomer shows a large break strain of ≈2260% and a record‐high toughness (ca. 460 MJ m−3), which arises from its dynamic microphase‐separated microstructure resulting in increased entropic elasticity, and strain‐hardening at large strains. The elastomer also exhibits a self‐extinguishing ability thanks to the presence of both phosphorus‐containing units and π–π stacking interactions. Its promising applications as a reliable yet recyclable substrate for strain sensors are demonstrated. The work will help to expedite next‐generation sustainable advanced elastomers for flexible electronics and devices applications. By introducing well‐designed dynamic π–π stacking motifs and phosphorus‐containing moieties, a mechanically strong, supertough and fire retardant polyurethane elastomer is developed, demonstrating a high tensile strength of ≈57 MPa, a large break strain of ≈2260%, a record‐high toughness (ca. 460 [±15] MJ m−3) and a self‐extinguishing ability, which hold great promise for flexible electronics and devices applications.

Flame retardants are currently used in a wide range of industry sectors for saving lives and property by mitigating fire hazards. The growing fire safety requirements for materials boost an escalating demand for consumption of fire retardants. This has significantly driven both the industry and scientific community to pursue sustainable fire retardants, but what makes a sustainable flame retardant? Here an overview of recent advances in sustainable flame retardants is offered, and their renewable raw materials, green synthesis and life cycle assessments are highlighted. A discussion on key challenges that hinder the innovation of fire retardants and design principles for creating truly sustainable yet cost‐effective fire retardants are also presented. This short work is expected to help drive the development of sustainable, cost‐effective fire retardants, and expedite the creation of a more sustainable and safer society. Rethinking the pathways to sustainable fire retardants, from the perspective of sustainability, costs, and efficiency.

High‐performance polymers have proliferated in modern society across a variety of industries because of their low density, good chemical stability, and superior mechanical properties. However, while polymers are widely applied, frequent fire disasters induced by their intrinsic flammability have caused massive impacts on human beings, the economy, and the environment. Supramolecular chemistry has recently been intensively researched to provide fire retardancy for polymers via the physical barrier and char‐catalyzing effects of supramolecular aggregates. In parallel, the noncovalent interactions between supramolecular and polymer chains, such as hydrogen bonding, π–π interactions, metal–ligand coordination, and synergistic interactions, can endow the matrix with enhanced mechanical strength. This makes it possible to integrate physical–chemical properties and noncovalent interactions into one supramolecular aggregate‐based high‐performance polymeric system on demand. However, fulfilling these promises needs more research. Here, we provide an overview of the latest research advances of fire‐retardant and high‐strength polymer materials based on supramolecular structures and interactions of aggregates. This work reviews their conceptual design, characterization, modification principles, performances, applications, and mechanisms. Finally, development challenges and perspectives on future research are also discussed. This work provides an overview of fire‐retardant and high‐strength polymer materials based on supramolecular structures and interactions of aggregates, including their conceptual design, characterization, modification principles, performances, applications, mechanisms, challenges, and future perspectives.

MXene‐based thermal camouflage materials have gained increasing attention due to their low emissivity, however, the poor anti‐oxidation restricts their potential applications under complex environments. Various modification methods and strategies, e.g., the addition of antioxidant molecules and fillers have been developed to overcome this, but the realization of long‐term, reliable thermal camouflage using MXene network (coating) with excellent comprehensive performance remains a great challenge. Here, a MXene‐based hybrid network comodified with hyaluronic acid (HA) and hyperbranched polysiloxane (HSi) molecules is designed and fabricated. Notably, the presence of appreciated HA molecules restricts the oxidation of MXene sheets without altering infrared stealth performance, superior to other water‐soluble polymers; while the HSi molecules can act as efficient cross‐linking agents to generate strong interactions between MXene sheets and HA molecules. The optimized MXene/HA/HSi composites exhibit excellent mechanical flexibility (folded into crane structure), good water/solvent resistance, and long‐term stable thermal camouflage capability (with low infrared emissivity of ≈0.29). The long‐term thermal camouflage reliability (≈8 months) under various outdoor weathers and the scalable coating capability of the MXene‐coated textile enable them to disguise the IR signal of various targets in complex environments, indicating the great promise of achieved material for thermal camouflage, IR stealth, and counter surveillance. A high‐performance thermal camouflage material is designed and successfully fabricated by decorating MXene network with hyaluronic acid (HA) and hyperbranched polysiloxane (HSi). Besides excellent mid‐infrared (IR) thermal camouflage, such material also integrates multiple advantages into itself, including being large‐scale, mechanically flexible, weather‐resistant, and thus showing great potential for stealth applications.

HighlightsA nanofiber composite reinforced organohydrogel with multifunctionality is prepared.The composite organohydrogel possesses multiple interfacial bondings and multi-level strengthening and toughening mechanism is proposed.The composite organohydrogel exhibits long-term strain sensing stability and can be used for high performance electromagnetic interference shielding. Composite organohydrogels have been widely used in wearable electronics. However, it remains a great challenge to develop mechanically robust and multifunctional composite organohydrogels with good dispersion of nanofillers and strong interfacial interactions. Here, multifunctional nanofiber composite reinforced organohydrogels (NCROs) are prepared. The NCRO with a sandwich-like structure possesses excellent multi-level interfacial bonding. Simultaneously, the synergistic strengthening and toughening mechanism at three different length scales endow the NCRO with outstanding mechanical properties with a tensile strength (up to 7.38 ± 0.24 MPa), fracture strain (up to 941 ± 17%), toughness (up to 31.59 ± 1.53 MJ m−3) and fracture energy (up to 5.41 ± 0.63 kJ m−2). Moreover, the NCRO can be used for high performance electromagnetic interference shielding and strain sensing due to its high conductivity and excellent environmental tolerance such as anti-freezing performance. Remarkably, owing to the organohydrogel stabilized conductive network, the NCRO exhibits superior long-term sensing stability and durability compared to the nanofiber composite itself. This work provides new ideas for the design of high-strength, tough, stretchable, anti-freezing and conductive organohydrogels with potential applications in multifunctional and wearable electronics.

Highlights The as-fabricated waterborne polyurethane (WPU) nanocomposite film exhibits a 55.6% improvement in limiting oxygen index, 66.0% and 40.5% reductions in peak heat release rate and total heat release, respectively, and 93.3% increase in tensile strength relative to pure WPU film. The resultant WPU nanocomposite film presents a high thermal conductivity ( λ ) of 12.7 W m −1  K −1 and a low dielectric constant ( ε ) of 2.92 at 10 6  Hz. To adapt to the trend of increasing miniaturization and high integration of microelectronic equipments, there is a high demand for multifunctional thermally conductive (TC) polymeric films combining excellent flame retardancy and low dielectric constant ( ε ). To date, there have been few successes that achieve such a performance portfolio in polymer films due to their different and even mutually exclusive governing mechanisms. Herein, we propose a trinity strategy for creating a rationally engineered heterostructure nanoadditive (FG@CuP@ZTC) by in situ self-assembly immobilization of copper-phenyl phosphonate (CuP) and zinc-3, 5-diamino-1,2,4-triazole complex (ZTC) onto the fluorinated graphene (FG) surface. Benefiting from the synergistic effects of FG, CuP, and ZTC and the bionic lay-by-lay (LBL) strategy, the as-fabricated waterborne polyurethane (WPU) nanocomposite film with 30 wt% FG@CuP@ZTC exhibits a 55.6% improvement in limiting oxygen index (LOI), 66.0% and 40.5% reductions in peak heat release rate and total heat release, respectively, and 93.3% increase in tensile strength relative to pure WPU film due to the synergistic effects between FG, CuP, and ZTC. Moreover, the WPU nanocomposite film presents a high thermal conductivity ( λ ) of 12.7 W m −1  K −1 and a low ε of 2.92 at 10 6  Hz. This work provides a commercially viable rational design strategy to develop high-performance multifunctional polymer nanocomposite films, which hold great potential as advanced polymeric thermal dissipators for high-power-density microelectronics.

Driven by the principles of sustainable development and green chemistry, phosphorus‐free flame‐retardant systems have become a key focus in the development of high‐performance polymers because they feature improved ecological safety relative to phosphorus‐based systems. This review focuses on two main phosphorus‐free flame‐retardant strategies: (i) additive phosphorus‐free flame retardants and (ii) intrinsically phosphorus‐free flame‐retardant epoxy resins. Emphasis is placed on the relationship between chemical structure and comprehensive properties, including flame retardancy, thermal properties, and mechanical performance. The flame‐retardant modes‐of‐action for the phosphorus‐free flame‐retardant epoxy systems are also summarized. Finally, current challenges and future development opportunities are presented. This work is expected to facilitate the development of phosphorus‐free flame‐retardant systems. Phosphorus‐free flame‐retardant epoxy systems offer eco‐friendly, low‐toxicity solutions by avoiding hazardous byproducts. This work highlights structure–performance relationships, with emphasis on how rigid backbones, multifunctional groups, and crosslinked networks enhance char formation, flame retardancy, and mechanical strength. Advancements in molecular design position these systems as promising candidates for sustainable, high‐performance polymer materials.

Highlights Fabricating low-cost, high-performance, scalable polypropylene (PP)@graphene (G) nanocomposites from recycled PP fibers in waste masks by a simple electrostatic self-assembly hot-pressing method. The resultant PP@G presents a high thermal conductivity of 87 W m −1 K −1 and a high electromagnetic interference shielding effectiveness of 88 dB (1100 dB cm −1 ). Over 950 billion (about 3.8 million tons) masks have been consumed in the last four years around the world to protect human beings from COVID-19 and air pollution. However, very few of these used masks are being recycled, with the majority of them being landfilled or incinerated. To address this issue, we propose a repurposing upcycling strategy by converting these polypropylene (PP)-based waste masks to high-performance thermally conductive nanocomposites (PP@G, where G refers to graphene) with exceptional electromagnetic interference shielding property. The PP@G is fabricated by loading tannic acid onto PP fibers via electrostatic self-assembling, followed by mixing with graphene nanoplatelets (GNPs). Because this strategy enables the GNPs to form efficient thermal and electrical conduction pathways along the PP fiber surface, the PP@G shows a high thermal conductivity of 87 W m⁻ 1  K⁻ 1 and exhibits an electromagnetic interference shielding effectiveness of 88 dB (1100 dB cm −1 ), making it potentially applicable for heat dissipation and electromagnetic shielding in advanced electronic devices. Life cycle assessment and techno-economic assessment results show that our repurposing strategy has significant advantages over existing methods in reducing environmental impacts and economic benefits. This strategy offers a facile and promising approach to upcycling/repurposing of fibrous waste plastics.