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Despite great advances for flame-retardant polyamide 6 (PA6), there is still a lack of facile strategies for creating advanced flame-retardant PA6 composites without significantly compromising its thermal stability to date. In this work, flame retardant PA6 nanocomposites were fabricated by incorporation of carbon nanotubes (CNTs) and organic montmorillonite (OMMT) together with aluminum diisobutylphosphinite acid (ABPA) into PA6. CNTs, exfoliated clay sheets and APBA particles are finely dispersed within the PA6 matrix and a physical network is formed. The addition of CNTs can compensate the decrease in thermal stability for the PA6/APBA/OMMT ternary system and further improve the char yield. The PA6/ABPA/5MT/1NT quaternary system containing 6 wt% ABPA, 5 wt% OMMT and 1 wt% CNT achieves a LOI of 31.4% and passes V-0 rating during UL-94 tests. The peak of heat release rate of this PA6 quaternary system decreases by 74.4% as compared to pristine PA6.

The development of a green and facile strategy for fabricating ecofriendly, highly effective flame retardants has remain a major challenge. Herein, supermolecular aggregates of piperazine (PiP) and phytic acid (PA) have been self-assembled onto the graphene oxide (GO) surface in water to fabricate functionalized GO (PPGO). The chemical structure and morphology of PPGO are determined by the X-ray photoelectron spectroscopy, transmission electron microscopy and scanning electron microscopy along with the energy dispersive spectroscopy. Due to the introduction of organic component onto the surface of graphene oxide, the adhesion between PPGO and the epoxy resin (EP) matrix is enhanced. As a result, the storage modulus (E′) of EP composites is increased in addition to a better dispersion of PPGO. Compared with the pure EP, the flame resistance of EP/PPGO is significantly improved, exhibiting a 42% decrease in peak heat release rate (pHRR), 22% reduction in total heat release (THR). The reduced flammability of EP is attributed to the synergistic effects afforded by the gas dilution effect of piperazine, char-forming promotion effect of phytic acid and the creation of "tortuous path" barrier effect of GO during burning. This work offers a green and facile approach for creating highly effective graphene-based flame retardants.

The design of flame-retardant biocomposites based on biobased flame retardants (FRs) represents a promising direction for creating a sustainable world. To date, it remains a major challenge to expl...

Bamboo features the fastest growing speed and abundant in the plant kingdom. However, it remains a huge challenge to prepare large flat surface boards by directly sawing or cutting due to the hollow cylindrical shape of bamboo culms. We herein have demonstrated the preparation of facile scalable fabrication of larger flattened bamboo board without cutting it into arcs bamboo strips by high-press steam softening approach. The results show that modulus of elasticity (MOE) of bamboo decreases with increasing softening temperature from 100 °C to 160 °C, and increases 8.3% from 160 °C to 180 °C, which is still less than bamboo softened at 140 °C. Bamboo can be flattened after softening above 140 °C. In addition, the main components of bamboo have no obvious changes when the softening temperature is below 140 °C. Moreover, the density and MOE are reduced after softening due to the decomposition of chemical components and increases after flattening due to increasing densification of bamboo which makes the flattened bamboo structure more uniform and stable. Hemicellulose starts to decompose from 160 °C and the equilibrium moisture content (EMC) of soften bamboo is similar with flattened bamboo. It is also found that the volumetric swelling of the flattened bamboo is higher than that of soften bamboo. This work offers a facile methodology for promoting the high value-add utilization of bamboo biomass, and obtaining larger flatten bamboo board with high performance at a treatment condition of 160 ℃ and 8 min.

Cobalt-free Li and Mn-rich layered cathode materials are promising for next generation lithium ion batteries due to their high specific capacity and low cost. However, these materials are facing serious issues, such as structural collapse due to volume shrinkage during Ni2+ oxidation to Ni4+ and oxygen vacancy generation over 4.5V. In this work, we report a strategy to address the issue of volume shrinkage caused by structural deformation via constructing a large-size rigid frame by simultaneously doping inactive and large radius atoms of Cd and S. This strategy significantly reduces the volume shrinkage when fully delithiated relative to the pristine material. The Cd- and S-doped cathode materials present a highly reversible structure, which were determined by using HAADF-STEM and in-situ XRD characterization. The doped Cd and S atoms act as supporting atoms and synergistically enlarge the layer spacing of crystalline from 0.455 to 0.483 nm. The in-situ XRD monitors the structural changes in real time during charging and discharging processes, further verifying structural stability during cycling. Due to the unique structural properites, an initial capacity of 268.5 mAh g−1 at 0.1 C along with a good rate capacity of 153.8 mAh g−1 at 5 C were achieved. Also, a capacity of 243.4 mAh g-1 at 0.1 C over 80 cycles indicate good cyclic stability of the co-doped Li- and Mn-rich layered cathode.

The development of environmentally benign, transparent, durable, and healable anti-fogging coating is vital for automobile windshields and food packaging in our daily production and life. The fabrication of existing anti-fogging coatings is often time-consuming in addition to potential toxicity issues. Here, we have reported a highly transparent and healable anti-fogging coating on the surface of poly(ethylene terephthalate) (PET) film by using bioderived pectin and tannic acid (TA) via a facile dip-coating method. The results show that the pectin/TA composite coating endows the PET film with excellent anti-fogging property without sacrificing the transparency of the PET films. This coating can maintain exceptional anti-fogging capabilities in both hot-vapor and cold-warm conditions. In addition, such anti-fogging coatings also exhibit good durability as the anti-fogging capability can be well-retained even after spray rinsing 5 times with high-speed water faucet. Moreover, the scratches or cuts on the coating can be completely healed within 4 minutes of triggering with water. The study provides an innovative methodology for the design of highly transparent, durable, and healable anti-fogging coatings, and offers promising value-added utilization of abundant and renewable biomass.

In this paper, we have reported a facile way to functionalize graphene oxide (GO) via assembling a supermolecular aggregate of piperazine (PiP) and phytic acid (PA) onto the GO surface (PPGO) without using any organic solvent. The functionalization of GO is confirmed by the X-ray photoelectron spectrum (XPS), transmission electron micrographs (TEM) and Raman spectrum. The introduction of 3 wt% PPGO into epoxy resin (EP/PPGO3) results in notable suppression on the fire risk of epoxy resin. In addition, cone calorimeter tests showed that the peak heat release rate (pHRR) was decreased from 727.4 kW/m2 to 367.5 kW/m2 (49%), and the peak smoke production rate (pSPR) was decreased from 0.2316 m2/s to 0.1379 g/s (40%). The improved flame-retardant performance of EP nanocomposites is most likely due to a tripartite cooperative effect from the key components (piperizine, phytic acid, and GO). This strategy demonstrates a facile and efficient approach for fabricating highly effective graphene-based flame retardants for polymers.

Ti3C2 MXenes, a novel two-dimensional material, have attracted lots of attention in biomedical filed for its large surface area and excellent near-infrared (NIR) responsiveness. In this paper, a pH/near-infrared (NIR) multi-responsive drug delivery platform consisted of hollow hydroxyapatite (HAP), chitosan (CS)/hyaluronic acid (HA) multilayers, gold nanorods (AuNRs) and MXene had been fabricated via a layer-by-layer (LbL) approach. Chitosan/hyaluronic acid multilayers were deposited on the surface of hollow HAP to retard the burst release of DOX in the initial delivery stage. MXenes and AuNRs equipped on the surface of hybrid matrix greatly enhanced the photothermal conversion efficiency of the microcapsules. Due to the collapse of electrostatic force among chitosan/hyaluronic acid multilayers and the dissolution of HAP under acidic condition, as well as the synergistically enhanced photothermal effect between MXene and AuNRs, HAP/CS/HA/MXene/AuNRs microcapsules exhibited outstanding pH-/NIR-responsive drug delivery properties. The present paper provides an attractive method to prepare chitosan/hyaluronic acid based pH/NIR multi-responsive hybrid microcapsules with excellent photothermal conversion efficiency and biocompatibility, which has great potential in the field of remotely controlled drug delivery.

The design of environmentally benign bio-adsorbents for the removal of phosphate from aqueous medium was an economic and effective way for controlling eutrophication. Herein, we prepared three kinds of TiO

Fire has been giving rise to enormous loss of life and property worldwide annually. Early fire warning represents an active and effective means to avoid potential fire hazards before huge losses occur. Despite encouraging advances in early fire warning systems, to date there remains an urgent lack of the design of a durable, flexible, and universal early fire warning sensor for large-area practical applications. Herein, facile fabrication of a durable, flexible, large-scale early fire-warning sensor is demonstrated through constructing a hierarchical flame retardant nanocoating, composed of graphene oxide, poly(dimethylaminoethyl methacrylate), and hexagonal boron nitride, on cotton fabric in combination with the parallelly patterned conductive ink as built-in electrodes. As-designed large-scale sensor (33 cm and extendable) exhibits a short alarming time of3 s in response to external abnormal high temperature, heat, or fire. In addition to high washability, flexibility, resistance to abrasion and wear, this hierarchical nanocoating can self-extinguish, thus enabling the sensor to continue warning during fire. This work offers an inventive concept to develop a universal and large-scale very early fire-monitoring platform, which opens up new opportunities for their practical applications in effectively reducing fire-related casualties and economic losses.

Polycarbonate (PC) features high transparency and balanced mechanical properties, and thus is being growingly used for producing many high-end products, e.g., construction facades, sensors and 5G equipment. For these applications, PC is required to combine satisfactory fire retardancy and great toughness while retain its mechanical strength and optical transparency. However, existing either fire retardants or toughening agents fail to enable PC to achieve such a required performance portfolio due to their improper molecular designs. To overcome this challenge, we, herein, rationally design a series of sulfonated ionomeric fire retardants (sSEBS-M, M = Na+, Zn2+, Ce3+) by sulfonating and neutralizing styrene-ethylene-butylene-styrene (SEBS). The sSEBS-M can be well-dispersed within the PC matrix with phase domain sizes less than 500 nm. Chemical structures of sSEBS-M and their dispersion within the polymer matrix strongly correlate to their comprehensive performances in PC. Among three sSEBS-M ionomers, sSEBS-Ce endows PC with better comprehensive performances. With 1.5 wt% of sSEBS-Ce, the final PC achieves a high limiting oxygen index of 33.5% and a desired UL-94 V-0 rating, in addition to a 53% reduction in peak heat release rate and a comparable transparency to virgin PC. Moreover, its impact toughness and ductility are enhanced by 40% and 116% with tensile strength well-preserved. The integrated performance portfolios are superior to previous counterparts. This work offers a novel strategy for the design of multifunctional ionomer-based fire retardants for creating high-performance PC and reveals its structure-composition-property relationship in PC, which will enable PC to realize its practical applications in above-mentioned industries.

International audience; Renewable polylactide (PLA) features good biodegradability, high optical transparency and mechanical strength. However, inherent flammability severely restricts its practical applications in packaging, fabric and electronics. Polyphosphoramides have recently demonstrated high fire-retardant effectiveness in PLA, but their synthesis usually involves the use of a large volume of toxic organic solvents, in addition to their negative impacts on the transparency of PLA. Herein, we report a one-pot green solvent-free approach for massively synthesizing a silicon (Si)-containing polyphosphoramide (DM-Si). The results show that with only 1.0 wt% of DM-Si, the resultant PLA material exhibits desirable fire retardancy, e.g., a UL-94 V-0 rating and a limiting oxygen index of 27.9%, and a 68% increase in toughness relative to virgin PLA. Moreover, both the tensile strength and transparency of PLA are well-preserved. This work provides an eco-benign yet facile strategy for the synthesis of efficient flame re-tardants for bioplastics with balanced mechanical strength and transparency, which hold great promise as sus-tainable materials for many industrial applications.

This work reports a novel triple-functional electronic skin (e-skin) which shows both wonderful thermal-magnetic-mechanical sensing performance and interesting magnetic actuation behavior. The flexible e-skin comprises thermo-sensitive, magnetic, and conductive tri-components, and their sensitive characteristics under 5-70 °C, 0-1200 mT, and 0.1-5.1 MΩ are studied, respectively. Owing to the unique piezoresistive characteristic and magnetorheological effect, the e-skin exhibits a rapid response time (38 ms) to the external stimuli. The assembled e-skin with the triple-layer structure can act as a functional sensor to monitor various human motions, magnetic fields, and environmental temperatures. Based on this e-skin, an intelligent magneto-active gripper is further developed, and it can be used to grasp and transport targets by the actuated force of magnetic field under various working conditions. Importantly, the multi-functional sensing capability endows the gripper with real-time deformation and ambient temperature perception characteristics. As a result, because of the ideal multi-field coupling sensing and magnetic active features, this e-skin shows a wide prospect in wearable electronics, man-machine interactions, and intelligent transport systems.

Bio-based flame retardants represent one of the most promising directions for next-generation flame retardants due to their sustainability, environmental benefits and comparable efficiency to current non-bio-based counterparts. Because of lignin's unique aromatic structure and high charring capability, recent years have witnessed the great flame-retardancy potential of pristine lignin and its derivatives in a wide range of polymeric materials. Unfortunately, to date there has been no critical review on the preparation, modification and application of lignin-derived flame retardants for polymeric materials. This review focuses on the flame-retardancy effects of pristine lignin and lignin chemically modified by introducing the elements phosphorus and/or nitrogen, as well as their synergistic effects with existing flame-retardant additives. This review also comprehensively compares the flame-retardancy performances of different lignin-derived flame retardants in various polymeric matrices, such as polylactic acid, polypropylene and polyamide 11. Following the conclusions, future perspectives are also presented along with new opportunities for the development of more efficient and effective lignin-based flame retardants for polymeric materials.

The ongoing Covid-19 pandemic has raised the need for urgent antibacterial requirements for many commercially important polymers, e.g., Epoxy resins (EPs). Meanwhile, intrinsic flammability and poor impact toughness are two big obstacles that greatly impede the practical applications of EPs. Hence, it has been imperative but highly challenging to create advanced EPs combining satisfactory antibacterial, fire-retardant and mechanically robust performances so far. Here, we report a reactive multifunctional heterostructure, copper-organophosphate-MXene (CuP-MXene) by rational design. Our results show that with 5.0 wt% of CuP-MXene, in addition to achieving a high antibacterial efficiency above 99.9%, the resultant EP nanocomposite exhibits satisfactory flame retardancy (UL-94 V-0 rating, peak heat release rate decreased by 64.4%) and improved mechanical properties (tensile strength, elastic modulus and impact strength increased by 31.7%, 38.9%, and 25.0%, respectively) relative to virgin EP, outperforming its previous counterparts. Such a desirable performance portfolio arises from multiple synergistic effects between CuP and MXene. This work provides a general strategy for the design of multifunctional nanoadditives and advanced functional polymers, and creates more opportunities for industrial applications of EP in the areas of coatings, medical devices and furniture.

Owing to the increasing heat dissipation problem of advanced modern electronic devices, polymer composites with high thermal conductivity have received extensive attention in recent years. Here, the high thermally conductive composites are prepared with a polymer matrix of epoxidized natural rubber (ENR)/polylactic acid (PLA) blend and a nano-additive hybrid system of boron nitride (BN)/graphene oxide (GO). To promote the dispersion of filler in ENR/PLA matrix, BN was covalently bonded with GO. When the contents of BN/GO into ENR/PLA composites was 14 wt%, a massive 240% enhancement of thermal conductivity, recoverable performance (85% of tensile strength after post forming compared to that of original composites), self-healing effect (86% of tensile strength after self-healing compared to that of original composites, respectively. The proposed composites system (BN/GO/ENR/PLA) will provide valuable insights for the application of polymers in electronic devices.

Fire warning sensor capable of rapidly monitoring critical fire risk of combustible materials growingly plays a crucial role in reducing or avioding fire disaster under complicated environments. Unfortunately, to date the rational design of smart fire warning sensors that are reusable and weather-resistant remains a major challenge. Here, we report a facile and green strategy for fabricating biomimetic polyethylene glycol or polyvinyl pyrrolidone polymer decorated Ti3C2Tx MXene networks that possess exceptional flame resistance and sensitive fire cyclic warning performance. Novel fire warning sensors that were constructed based on the as-prepared inherently fire-retardant MXene networks exhibit ultrafast fire warning response and recovery time (~1.8 s and ~1.0 s), resistance switching behavior with >4 orders of magnitude, and stable fire cyclic warning capability for 100 cycles. Structural observation and analysis disclose that, upon flame attack, thermal pyrolysis of the polymer molecules facilitates the oxidation of MXene sheets to form a compact fish scale-like C/N dopped titania network, and meanwhile its electron excitation is thus activated to generate a sensitive resistance transition to trigger a rapid fire cyclic warning signal. More improtantly, the multifunctional MXene networks treated with silane modification not only endow combustible substrate with excellent super-hydrophobicity and outstanding flame resistance, but provide reusable and weather-resistant fire warning responses even after one-year outdoor exposure. Therefore, this work provides an innovative concept of advanced MXene composites and design of fire cyclic warning sensors for fire safety and prevention.

Removing phosphate ions from eutrophic waters is of paramount importance; however, the design of low-cost, high-performance adsorbents for phosphorus removal has remained a huge challenge. Herein, we have demonstrated the fabrication of a low-cost, eco-friendly absorbent, LPC@La(OH)3, by loading lanthanum hydroxide nanorods within lignin-derived porous carbon for superfast and highly efficient phosphorus removal. As-prepared LPC@La(OH)3 exhibits a high adsorption capacity of 60.24 mg P L–1 and a high lanthanum usage efficiency. Our results show an ultrafast removal of up to 99.5% phosphate in 10 min when the initial concentration is 2 mg P L–1. Moreover, LPC@La(OH)3 can efficiently reduce the phosphate concentration to meet the below U.S. Environmental Protection Agency limits (50 μg P L–1) for eutrophication prevention. More importantly, it shows a high phosphate absorption ability over the wide range of pH 3–7, in addition to a high adsorption selectivity toward phosphate and high stability during adsor...

Epoxies are widely used in many engineering applications, however, their fracture energy remains less than desired and conventional toughening agents usually lead to compromised tensile strength. In this study, a simple one-pot blending method was used, in which both graphene oxide and a block ionomer were blended with epoxy resin. Herein, we reported that increases of ∼200% in fracture energy (GIC), 48% in uniaxial tensile strength (σt) and 340% in tensile strain could be achieved by incorporating 1.0 wt% graphene oxide into an epoxy matrix with 20 wt% sulfonated polystyrene-block-poly(ethylene-co-butylene)-block-polystyrene (SSEBS). In addition, the glass transition temperature (Tg) of the nanocomposite increased with increasing graphene oxide (GO) content and the storage modulus (E′) decreased when the GO content was less than 0.50 wt% owing to the introduction of the block ionomer SSEBS. Careful examination of the nano-morphology of SSEBS revealed that it improved the dispersion of the graphene oxide in and enhanced its interaction with the epoxy matrix, hence simultaneously strengthening and toughening the epoxy resin.

Despite substantial advances, it remains imperative but challenging to develop high-performance polymer/graphene nanocomposites combining with excellent mechanical, thermal, and fire-retardant properties. In this work, a novel kind of graphene-based multifunctional nanofiller (La@PN-RGO) was fabricated via the nitrogen doping and the decoration with organophosphorus and lanthanum based on graphene oxide, which is then incorporated into acrylonitrile–butadiene–styrene (ABS) resin via melt blending to obtain resultant ABS nanocomposites. As expected, the La@PN-RGO nanosheets were well dispersed in ABS composites. Attractively, with only 1.0 wt % of La@PN-RGO incorporated into ABS matrix, the peak heat release rate (PHRR) and total smoke production (TSP) were significantly reduced by 38% and 36%, which is much superior to its counterparts at the same nanofillers loading level. The notably enhanced fire safety was primarily attributed to the rare earth catalysis accompanied by the lamellae blocking effect and...

Expanding the application range of flame-retardant polymer biocomposites remains a huge challenge for a sustainable society. Despite largely enhanced flame retardancy, until now the resultant poly(lactic acid) (PLA) composites still suffer reduced tensile strength and impact toughness due to improper material design strategies. We, herein, demonstrate the design of a green flame retardant additive (ammonium polyphosphate (APP)@cellulose nanofiber (CNF)) via using the cellulose nanofibers (CNFs) as the green multifunctional additives hybridized with ammonium polyphosphate (APP). The results show that PLA composite with 5 wt % loading of APP@CNF can pass the UL-94 V-0 rating, besides a high limited oxygen index of 27.5%, indicative of a significantly enhanced flame retardancy. Moreover, the 5 wt % of APP@CNF enables the impact strength (σi) of the PVA matrix to significantly improve from 7.63 to 11.8 kJ/m2 (increase by 54%), in addition to a high tensile strength of 50.3 MPa for the resultant flame-retardant PLA composite. The enhanced flame retardancy and mechanical strength performances are attributed to the improved dispersion of APP@CNF and its smaller phase size within the PLA matrix along with their synergistic effect between APP and CNF. This work opens up a facile innovative methodology for the design of high-performance ecofriendly flame retardants and their advanced polymeric composites.

Silicon monoxide (SiO) has emerged as one promising anode material for lithium-ion battery owing to its high theoretical capacity and relatively small volume change compared with silicon based anode. However, poor conductivity extremely restricts its specific capacity and cycling stability of SiO, C-SiO is most considered to be addressed this issue. Despite that, the effect of the orderly arrangements of carbon coatings on the overall electrochemical performance of SiO anode remains unclear. It is more important to explore the structure of carbon coatings on the electrochemical properties of silicon based anode. Herein, we have much improved orderly array of carbon coatings for C-SiO by introducing 3% TiO2, and evidenced by Raman spectroscopy and HRTEM. The electrochemical results show that the TC-SiO with 3% TiO2 exhibits striking advantages in cycling stability, high rate charge/discharge and interfacial stability properties compared with C-SiO with disorder carbon coatings. This work provides a new strategy for further improving conductivity and interfacial stability of C-Si based anode materials.

The design of an environmentally benign cost-effective adsorbent for superfast removal of phosphate from wastewater is vital but remains a huge challenge. Herein, we have developed a recyclable, low-cost nanostructured bio-adsorbent, poly(ethyleneimine)-graft-alkali lignin loaded with nanoscale lanthanum hydroxide (AL–PEI–La), by a facile fabrication. AL–PEI–La was found to exhibit an excellent adsorption performance toward phosphate ions. For example, 94% of the phosphate ions from 40 mL of a solution containing 50 mg P L−1 phosphate ions was removed in 60 min. Additionally, in a low phosphate concentration wastewater of 2.0 mg P L−1, 95% of phosphate was removed in just 1 min and 99% of phosphate was removed in 15 min and the phosphate concentration dramatically decreased below 50 μg P L−1, which met the standard of eutrophication prevention. The adsorption capacity of AL–PEI–La for phosphate ions was found to be 65.79 mg P g−1, which is 33 times larger than that of lignin. AL–PEI–La shows strong anti-jamming capability in terms of pH value (3.0–9.0) and the co-existing ions of the aqueous solution exhibiting highly selective capacity for phosphate removal. The interactions between surface precipitation and ligand exchange are predominantly responsible for the adsorption process. Importantly, it shows a good reusability and 85.76% of the original adsorption capacity remains after 3 cycles. Thus, the as-designed nanostructured bio-adsorbent with exceptional adsorption effectiveness and efficiency is expected to find extensive applications for remediating the phosphate-contaminated waters.

The global micro- and nano-plastic issue has greatly triggered the development of advanced biodegradable polymeric materials. The creation of biodegradable polyvinyl alcohol (PVA)/phytic acid (PhyAc) composite represents a sustainable solution. However, it remains unclear how PhyAc molecules affect intermolecular hydrogen-bonding (H-bonding), structure, chain dynamics and mechanical properties of PVA so far. Herein, we explore structure, chain dynamics and mechanical properties of PVA/PhyAc composite by combining molecular dynamics simulation and experimental. The number of PVA-PhyAc H-bonds per PhyAc molecule and that of total H-bonds show different PhyAc content dependence. The PVA composite with 1.9 wt% of PhyAc shows a lower free volume and a smaller diffusion coefficient. Meanwhile, the glass transition temperature ( Tg) of PVA reaches the maximum value at ca. 1.25 wt% of PhyAc. Interestingly, 10 wt% PhyAc endows PVA with the highest tensile strength in addition to a good antibacterial capability. This work reveals how small molecules affect structure and mechanical properties of polymers and contributes to expanding practical applications of PVA/PhyAc in industry.

Although the flammability of biodegradable poly(lactic acid) (PLA) has been effectively addressed so far, the resultant flame retardant PLA still displays a high brittleness, extremely restricting its wide applications in electrical, automobile and aerospace fields. In this work, we have demonstrated the fabrication of flame retardant and tough PLA composites by combining ammonia polyphosphate (APP) and poly(ethylene glycol) (PEG) with a molecular weight of 20,000 via the melt-blending strategy. The results show that the peak heat release rate of PLA can reduce by 14% in cone tests and a V-0 rating is achieved in vertical burning tests by adding 7 wt% of APP and 14 wt% PEG. Moreover, such PLA composite shows a high strain at break of 280% and impact strength of 14.9 kJ/m2, respectively increasing by thirty-eight-fold and two-fold relative to the PLA bulk. The results strongly indicate that flammability and brittleness of the PLA are strikingly reduced. This work provides an integrated strategy for creating advanced green polymer composites with exceptional flame resistance and toughness.

Thermoplastic polyurethane (TPU) features many important industrial applications, but intrinsic flammability extremely impedes its practical applications. Current fire-retardant strategies often lead to improved flame retardancy but reduced mechanical properties (strength, ductility, and toughness). Hence, to date it has been unsuccessful to design advanced TPU materials that are strong, stretchable, tough, fatigue-and fire-resistant to meet increasing performance portfolio requirements. Here, we report a hybridized fire retardant (Zr-MXene) by in situ facilely loading zirconium amino-tris-(methylenephosphonate) (Zr-AMP) onto the titanium carbide (MXene) surface. Our results show that with 1 wt% of Zr-MXene, the resultant TPU nanocomposites demonstrate a record break strain (2060%) and toughness (316 MJ/m3) to date, in addition to increased tensile strength by 43.4% and improved fatigue resistance relative to the TPU matrix, because of favorable interfacial hydrogen-bonding. Moreover, the resultant TPU material exhibit significantly reduced flammability as a result of the combined physical barrier, catalytical carbonization and diluting effects of Zr-MXene. This work provides a promising strategy for the creation of multifunctional MXene and its polymeric nanocomposites, which hold great promise for many industrial applications.

Polyurethane (PU) sponge has a wide range of applications in our daily life. Unfortunately, the PU sponge is highly flammable and becomes a breeding ground for bacteria, thereby threatening human health and life. To date, it remains a challenge to improve the flame retardant and antibacterial properties of PU sponge simultaneously without destroying its inherent elasticity and flexibility. Here we report a novel composite coating on the PU sponge using bioderived phytic acid and sodium lignosulfonate via a facile soaking method. Compared to the pristine sponge, the coated PU sponge can reach a 32% reduction in peak heat release rate during cone calorimeter test, and prevent melt dripping after being ignited by a butane torch and the flame can be self-extinguished after the torch is removed. The resultant composite coating also demonstrates a killing rate of 99% against Staphylococcus aureus. Meanwhile, the coated PU sponge can retain the inherent elasticity and flexibility even after 500 cycles of compression. Furthermore, the coating materials are easily recyclable, which provide a useful reference for multifunctional treatment of sponge and cyclic utilization of resources.

Electromagnetic interference has become a serious pollution concern in modern society, which has significantly driven the development of lightweight electromagnetic interference shielding materials based on porous carbon/polymer nanocomposites. This work discusses the state-of-the-art methods for fabricating polymer foams and carbon foams, aerogels, and sponges for electromagnetic interference shielding. In order to obtain an ideal electromagnetic interference shielding effectiveness, it is crucial to create carbon/polymer nanocomposites with effective conductive networks at low filler loadings. To this end, there have been three design strategies, including the use of carbon foams with polymer backfilling, the use of carbon-based hybrid fillers, and the formation of segregated structures in conductive polymer composite. This review also discusses electrical conductivity and electromagnetic interference shielding performances as well as associated mechanisms behind of lightweight carbon-polymer nanocomposites, and their potential applications are summarized. Some key challenges on lightweight polymer-carbon nanocomposites as electromagnetic interference shielding materials are presented followed by some future perspectives.

Effective utilization of abundant industrial lignin has growingly attracted much attention besides potential environmental issues. Although chemical graft polymerization modification is one facile strategy for extending its applications, it remains an intractable challenge to select a highly efficient initiation system. We herein have attempt to understand the CaCl2–H2O2 system in initiating the graft polymerization of acrylic monomers onto acetic acid lignin (AAL) and biobutanol lignin (BBL). The initiation system is found to be highly efficient and selective, as proved by the successful graft of polyacrylates onto them, and a possible mechanism is also proposed. Thermal analysis shows that the graft modification results in a higher glass transition temperature and higher thermal stability of lignin. The graft modification make both AAL and BBL become more hydrophobic than before modification. Moreover, adding a small amount of lignin-graft-polyacrylate can considerably improve the UV blocking capability...

Natural fibers reinforced benzoxazine bio‐composites are one class of highly attractive engineering materials in automobile, train and aerospace fields because of high thermal stability, good mechanical and improved biodegradability properties. Unfortunately, their poor interface and flammability issues remain unsatisfactorily addressed to date. Herein, we have demonstrated the fabrication of benzoxazine semi‐biocomposites reinforced by ramie fabric which was coated with bio‐based poly(diphenolic acid‐phenyl phosphate) (poly[DPA‐PDCP]) and polyethylenimine (PEI) via layer‐by‐layer self‐assembly method. The results show that the presence of poly(DPA‐PDCP)/PEI coating can significantly improve the interfacial adhesion between fabric and the resin matrix. This enables the tensile strength and flexural strength of as‐prepared semi‐biocomposite to increase by 53% (68.7 MPa) and 113% (120 MPa), respectively. In addition, the resultant semi‐biocomposite shows superior flame retardancy with a V‐0 rating achieved in the UL‐94 test. This work offers an effective approach to fabricate strong and flame retardant benzoxazine semi‐biocomposites. POLYM COMPOS., 39:E480–E488, 2018. © 2017 Society of Plastics Engineers

Balancing the size of the primary Si unit and void space is considered to be an effective approach for developing high performance silicon-based anode materials and is vital to create a lithium ion battery with high energy density. We herein have demonstrated the facile fabrication of coralloid-like nanostructured silicon composites (c-nSi/SiOx@Cy) via sulfuric acid etching the Al60Si40 alloy, followed by a surface growth carbon layer approach. The HRTEM images of pristine and cycled c-nSi/SiOx@Cy show that abundant nanoscale internal pores and the continuous conductive carbon layer effectively avoid the pulverization and agglomeration of Si units during multiple cycles. It is interesting that the c-nSi/SiOx@C4.0 anode exhibits a high initial Coulombic efficiency of 85.53%, and typical specific capacity of over 850 mAh g–1 after deep 500 cycles at a current density of 1 A g–1. This work offers a facile strategy to create silicon-based anodes consisting of highly dispersed primary nano-Si units.

Despite extraordinary mechanical properties and excellent biodegradability, poly(lactic acid) (PLA) still suffers from a highly inherent flammability, restricting its wide applications in the electric and automobile fields. Although a wide range of flame retardants have been developed to reduce the flammability, so far, they normally compromise the mechanical strength of PLA. Herein, we have demonstrated the fabrication of a novel core–shell nanofibrous flame-retardant system, PN-FR@CNF, through in situ chemically grafting the phosphorus–nitrogen-based polymer onto the cellulose nanofiber (CNF) surface. The results show that adding 10 wt % PN-FR@CNF enables PLA to achieve a V-0 flame resistance rating during vertical burning tests and to exhibit a dramatically reduced peak heat release rate in cone calorimetry measurements, indicating a significantly reduced flammability. In addition, the tensile strength of PLA also increases by around 24% (about 72 MPa). This work offers an innovative methodology for th...

With growingly demands for better performances in electronic-related applications, further improving thermal and fire safety of nylon 612 (PA612) becomes extremely pressing. In this work, we have reported the fabrication of flame retardant and thermally stable and conductive PA612 composites by using two-dimensional alumina platelets. Alumina platelets are observed being uniformly dispersed within the PA612 matrix. Thermal analysis demonstrates that addition of alumina platelets noticeably increases thermal stability and conductivity of PA612. Cone calorimetry results show that 40 wt% of alumina platelets addition decreases the peak heat release rate (pHRR) and total smoke production of PA612 by 54% and 29%, respectively, indicating largely enhanced flame resistance. Rheology tests demonstrate that there exists a nearly qualitative correlation between the flammability (pHRR) and viscoelastic behaviors (storage modulus). This work offers a new approach for creating advanced polymer composites with enhanced thermal and flame retardancy properties by using alumina platelets as multifunctional filler.

Despite excellent ductility and dimension stability, the relatively low mechanical strength and stiffness of PA612 extremely restrict its engineering applications. We herein have demonstrated the fabrication of high-performance PA612 composites combining superior mechanical and abrasion resistance properties by choosing two dimensional alumina platelets with a relatively low aspect ratio (∼35). Infrared spectra show that Al2O3 forms strong hydrogen-bond interactions with PA612. Tensile results demonstrate that adding 30 wt% of Al2O3 platelets increases the tensile strength and elastic modulus of PA612 by 55% (∼73 MPa) and 128% (∼3.38 GPa), respectively. In addition, the specific wear rate is reduced by about 61%. Such remarkable improvements in mechanical and abrasion resistance properties are mainly due to the high strength and stiffness of alumina platelets and the strong interfacial interactions with the PA612 matrix. This work offers one new methodology for creating advanced polymer composites by choosing suitable building blocks and by regulating the interfacial interactions.

Inspired by interfacial interactions of protein matrix and the crystal platelets in nacre, herein, a super-tough artificial nacre was produced through constructing the synergistic interface interactions of π-π interaction and hydrogen bonding between graphene oxide (GO) nanosheets and sulfonated styrene-ethylene/butylene-styrene copolymer synthesized with multifunctional benzene. The resultant GO-based artificial nacre showed super-high toughness of 15.3 ± 2.5 MJ/m3, superior to natural nacre and other GO-based nanocomposites. The ultra-tough property of the novel nacre was attributed to synergistic effect of π-π stacking interactions and hydrogen bonding. This bioinspired synergistic toughening strategy opens a new avenue for constructing high performance GO-based nanocomposites in the near future.

The development of phosphorus-containing flame retardants combining good compatibility with matrix, low curing temperature, and mechanically reinforcing effect has remained a major challenge. Herein, we reported the synthesis of a liquid flame-retardant curing agent (DA) via the nucleophilic substitution between diphenylphosphinic chloride and 1-(3-aminopropyl)-imidazole (AI). DA exhibited good blending and latency towards epoxy resin (EP) at room temperature. According to DSC studies, DA could rapidly cure EP at moderate temperature. Compared with EP/AI sample, EP/DA samples displayed comparable or higher glass transition temperature (Tg) and enhanced mechanical properties due to the introduction of rigid diphenylphosphinyl group and improved cross-linking density. Moreover, DA improved the flame-retardant performances of EP thermoset. For instance, the LOI and UL94 rating of EP/DA-16 sample achieved 37.2 % and V-0, respectively. In addition, the peak of heat release rate (PHRR), average of heat release rate (AHRR), fire growth rate (FIGRA), and total heat release (THR) for EP/DA-16 sample reduced by 32 %, 42 %, 28 % and 27 % in comparison to EP/AI sample, respectively. DA was characterized by its good compatibility with EP, moderate curing temperature, fast curing rate, suitable thermal latency, mechanical reinforcing and flame-retardant effects, and thus it had a broad application prospect in various industrial fields.

Wooden structures in China&rsquo, s ancient buildings hold highly historical and cultural values. There is an urgent need to repair and replace the damaged wooden structures after hundreds and thousands of years of exposure to weather. Unfortunately, to date there is still a lack of insightful understanding on how the chemical structure, composition, and micro-morphology evolve over the long-term natural aging before artificial ancient timbers can be developed. This work aims to systematically examine the outer surface, middle layer, and inner surface of the same piece of Chinese fir (Cunninghamia lanceolate) collected from an ancient Chinese building. Based on qualitative and quantitative analysis, both cellulose and hemicellulose in aged woods are found to experience significant degrees of degradation. The crystalline regions of cellulose are also determined to undergo moderate degradation as compared to the control fresh wood. In comparison, the lignin basically remains unchanged and its content in the inner layer slightly increases, as evidenced by more free phenol groups determined. Relative to the outer and inner layer, the middle layer of the ancient wood shows the lowest degree of degradation close to that of the fresh wood. This work offers guidelines for fabricating artificial ancient woods to repair the destroyed ones in China&rsquo, s ancient architectures.

It has always been critical to develop high-performance polymeric materials with exceptional mechanical strength and toughness, thermal stability, and even healable properties for meeting performance requirements in industry. Conventional chemical cross-linking leads to enhanced mechanical strength and thermostability at the expense of extensibility due to mutually exclusive mechanisms. Such major challenges have recently been addressed by using noncovalent cross-linking of reversible multiple hydrogen-bonds (H-bonds) that widely exist in biological materials, such as silk and muscle. Recent decades have witnessed the development of many tailor-made high-performance H-bond cross-linked polymeric materials. Here, recent advances in H-bond cross-linking strategies are reviewed for creating high-performance polymeric materials. H-bond cross-linking of polymers can be realized via i) self-association of interchain multiple H-bonding interactions or specific H-bond cross-linking motifs, such as 2-ureido-4-pyrimidone units with self-complementary quadruple H-bonds and ii) addition of external cross-linkers, including small molecules, nanoparticles, and polymer aggregates. The resultant cross-linked polymers normally exhibit tunable high strength, large extensibility, improved thermostability, and healable capability. Such performance portfolios enable these advanced polymers to find many significant cutting-edge applications. Major challenges facing existing H-bond cross-linking strategies are discussed, and some promising approaches for designing H-bond cross-linked polymeric materials in the future are also proposed.