To improve the flame resistance of polypropylene(PP)/carbon fiber(CF)composite materials,triazine char-forming agent(TCA)was compounded with ammonium polyphosphate(APP)or modified APP(CS-APP)in a 2:1 ratio to prepare ...To improve the flame resistance of polypropylene(PP)/carbon fiber(CF)composite materials,triazine char-forming agent(TCA)was compounded with ammonium polyphosphate(APP)or modified APP(CS-APP)in a 2:1 ratio to prepare intumescent flame retardant(IFR)and the modified intumescent flame retardant(CS-IFR)in this paper.Flame retardancy and thermal degradation behaviors of the composites modified by IFR and CS-IFR were characterized by Fourier Transform Infrared(FTIR),contact angle measurement,oxygen index(OI),vertical burning tests(UL-94),thermogravimetric analyer(TGA),and thermogravimetric analyzer coupled with Fourier transform infrared(TG-FTIR).It was found that 25.0 phr of IFR and 24.0 phr of CS-IFR could improve the LOI value of PP/CF composites to 28.3%and 28.9%,respectively.At the same time,a UL-94 V-0 rating was achieved.The experimental results show that the IFR and CS-IFR prepared could effectively improve the flame retardancy and thermostability of PP/CF composites,and they would greatly expand the application range of PP/CF composite materials.展开更多
Lithium-sulfur(Li-S)batteries are one of the most promising modern-day energy supply systems because of their high theoretical energy density and low cost.However,the development of high-energy density Li-S batteries ...Lithium-sulfur(Li-S)batteries are one of the most promising modern-day energy supply systems because of their high theoretical energy density and low cost.However,the development of high-energy density Li-S batteries with high loading of flammable sulfur faces the challenges of electrochemical performance degradation owing to the shuttle effect and safety issues related to fire or explosion accidents.In this work,we report a three-dimensional(3D)conductive nitrogen-doped carbon foam supported electrostatic self-assembled MXene-ammonium polyphosphate(NCF-MXene-APP)layer as a heat-resistant,thermally-insulated,flame-retardant,and freestanding host for Li-S batteries with a facile and costeffective synthesis method.Consequently,through the use of NCF-MXene-APP hosts that strongly anchor polysulfides,the Li-S batteries demonstrate outstanding electrochemical properties,including a high initial discharge capacity of 1191.6 mA h g^(-1),excellent rate capacity of 755.0 mA h g^(-1)at 1 C,and long-term cycling stability with an extremely low-capacity decay rate of 0.12%per cycle at 2 C.More importantly,these batteries can continue to operate reliably under high temperature or flame attack conditions.Thus,this study provides valuable insights into the design of safe high-performance Li-S batteries.展开更多
Phase change materials(PCMs)offer a promising solution to address the challenges posed by intermittency and fluctuations in solar thermal utilization.However,for organic solid-liquid PCMs,issues such as leakage,low th...Phase change materials(PCMs)offer a promising solution to address the challenges posed by intermittency and fluctuations in solar thermal utilization.However,for organic solid-liquid PCMs,issues such as leakage,low thermal conductivity,lack of efficient solar-thermal media,and flamma-bility have constrained their broad applications.Herein,we present an innova-tive class of versatile composite phase change materials(CPCMs)developed through a facile and environmentally friendly synthesis approach,leveraging the inherent anisotropy and unidirectional porosity of wood aerogel(nanowood)to support polyethylene glycol(PEG).The wood modification process involves the incorporation of phytic acid(PA)and MXene hybrid structure through an evaporation-induced assembly method,which could impart non-leaking PEG filling while concurrently facilitating thermal conduction,light absorption,and flame-retardant.Consequently,the as-prepared wood-based CPCMs showcase enhanced thermal conductivity(0.82 W m^(-1)K^(-1),about 4.6 times than PEG)as well as high latent heat of 135.5 kJ kg^(-1)(91.5%encapsula-tion)with thermal durability and stability throughout at least 200 heating and cooling cycles,featuring dramatic solar-thermal conversion efficiency up to 98.58%.In addition,with the synergistic effect of phytic acid and MXene,the flame-retardant performance of the CPCMs has been significantly enhanced,showing a self-extinguishing behavior.Moreover,the excellent electromagnetic shielding of 44.45 dB was endowed to the CPCMs,relieving contemporary health hazards associated with electromagnetic waves.Overall,we capitalize on the exquisite wood cell structure with unidirectional transport inherent in the development of multifunctional CPCMs,showcasing the operational principle through a proof-of-concept prototype system.展开更多
Preparing both safe and high-performance lithium-ion batteries(LIBs) based on commonly used commercial electrolytes is highly desirable,yet challenging.To overcome the poor compatibility of conventional small-molecula...Preparing both safe and high-performance lithium-ion batteries(LIBs) based on commonly used commercial electrolytes is highly desirable,yet challenging.To overcome the poor compatibility of conventional small-molecular flame-retardants as electrolyte additives for safe LIBs with graphite anodes,in this study,we propose and design a novel low-cost flame-retardant oligomer that achieves an accurate and complete reconciliation of fire safety and electrochemical performance in LIBs.Owing to the integration of phosphonate units and polyethylene glycol(PEG) chains,this oligomer,which is a phosphonatecontaining PEG-based oligomer(PPO),not only endows commercial electrolytes with excellent flame retardancy but also helps stabilize the electrodes and Li-ion migration.Specifically,adding 15 wt% of PPO can reduce 70% of the self-extinguishing time and 54% of total heat release for commercial electrolytes.Moreover,LiFePO_(4)/lithium and graphite/lithium cells as well as LiFePO_(4)/graphite pouch full cells exhibit good long-term cycling stability.展开更多
Polyamide 6 (PA6) was employed as a charring agent of intumescent flame retardant (IFR) to improve the flame retardancy of ethylene-vinyl acetate copolymer (EVA). Different processing procedures were used to regulate ...Polyamide 6 (PA6) was employed as a charring agent of intumescent flame retardant (IFR) to improve the flame retardancy of ethylene-vinyl acetate copolymer (EVA). Different processing procedures were used to regulate the localization of IFR in the EVA matrix. Localizations in which IFR was dispersed in the PA6phase or in the EVA phase were prepared. The effect of the localization of IFR on the flame retardancy of EVA was investigated. The limited oxygen index (LOI), vertical burning (UL 94) and cone calorimeter test (CCT)showed that the localization of IFR in the EVA matrix exhibited a remarkable influence on the flame retardancy.Compared with EVA/IFR, a weak improvement in the flame retardancy was observed in the EVA/PA6/IFR blend withthe localization of IFR in the PA6 phase. When IFR was regulated from the PA6 phase to the EVA matrix,a remarkable increase in the flame retardancy was exhibited. The LOI was increased from 27.8%to 32.7%, and the UL 94 vertical rating was increased from V-2 to V-0. Moreover, an approximately 41.36%decrease in the peak heat release rate was exhibited. A continuous and compact intumescent charring layer that formed in the blends with the localization of IFR in the EVA matrix should be responsible for its excellent flame retardancy.展开更多
A novel phosphorus-nitrogen containing intumescent flame retardant (P-N IFR) was prepared via the reaction of dichlor-opentate with N-methylaniline. The structure of the product was confirmed by ^1H NMR, ^31p NMR, M...A novel phosphorus-nitrogen containing intumescent flame retardant (P-N IFR) was prepared via the reaction of dichlor-opentate with N-methylaniline. The structure of the product was confirmed by ^1H NMR, ^31p NMR, MS and IR. TGA analysis showed it has effective thermal stability.展开更多
The synergistic effects of silicotungstic acid (SiW12) as a catalyst in the phosphorus-nitrogen compounds AM-based intumescent flame-retardant (IFR) polypropylene (PP) were studied using the limiting oxygen index (LOI...The synergistic effects of silicotungstic acid (SiW12) as a catalyst in the phosphorus-nitrogen compounds AM-based intumescent flame-retardant (IFR) polypropylene (PP) were studied using the limiting oxygen index (LOI), the UL-94 test, thermogravimetric analysis (TGA), real time Fourier transform infrared (FTIR), laser Raman spectroscopy (LRS). The LOI data show that SiW12 added to PP/IFR systems has a synergistic FR effect with an IFR additive named AM. The TGA data show that SiW12 apparently increases the thermal stability of the PP/IFR systems at high temperature (T > 500degreesC). The FTIR results provide the positive evidence that IFR can improve the thermal stability of PP and SiW12 can induce a higher rate of formation of phosphoric acid and its derivatives. The LRS measurements provide useful information on the carbonaceous microstructures. In short, a suitable amount of SiW12 (1.5 wt%) exerts synergistic effects with the IFR by increasing the LOI value and the thermal stability at high temperature and promoting the formation of charred structures on the burning PP surface.展开更多
Three novel triazine-based charring-foaming agents (M2-CFA,M4-CFA,and M6-CFA) were synthesized successfully with only water as the solvent and were characterized by FT-IR and thermal gravimetric analysis (TGA).These t...Three novel triazine-based charring-foaming agents (M2-CFA,M4-CFA,and M6-CFA) were synthesized successfully with only water as the solvent and were characterized by FT-IR and thermal gravimetric analysis (TGA).These three charring-foaming agents and the byproduct 944-by were employed to study the effectiveness of the novel intumescent flame retardant dopant on the fire retardancy of polypropylene (PP) investigated through UL-94 and limiting oxygen index (LOI) tests.TGA results showed that the M4-CFA presented good char formation ability (char residue: 26.8% at 700 ℃).It was found that the sample with a 2/1 mass ratio of APP to M4-CFA exhibited the best flame retardancy among all the PP composites: 35.5% LOI and a V-0 rating of UL-94.Additionally,the microstructure and morphology of char residues were further studied by XRD,Raman spectroscopy and SEM.展开更多
Flame-retardant mechanism of magnesium oxychloride (M OC) in EP was in-vestigated by limiting oxygen index (LOI), XRD, SEM, TG-DTG and DSC. The results show that MOC performed well as an inorganic flame-retardant ...Flame-retardant mechanism of magnesium oxychloride (M OC) in EP was in-vestigated by limiting oxygen index (LOI), XRD, SEM, TG-DTG and DSC. The results show that MOC performed well as an inorganic flame-retardant in EP. When the content of MOC is 50%, the LOI of EP reaches 29.6% and mass of residual char reaches 9.6%. The flame retarde mechanism of MOC is due to the synergies of diluting, cooling, catalyzing char forming and obstructing effects.展开更多
The effect of Ti3C2 MXene nanosheets on the intumescent flame retardant(IFR)poly(lactic acid)(PLA)composites was investigated among a series of PLA/IFR/MXene,which were prepared by melt blending 0-2.0 wt%MXene,10.0 wt...The effect of Ti3C2 MXene nanosheets on the intumescent flame retardant(IFR)poly(lactic acid)(PLA)composites was investigated among a series of PLA/IFR/MXene,which were prepared by melt blending 0-2.0 wt%MXene,10.0 wt%-12.0 wt%IFR and PLA together.The results of limiting oxygen index(LOI)and vertical burning(UL-94)discover that the combination of 0.5 wt%MXene and 11.5 wt%IFR synergistically improves the fire safety of PLA to reach UL-94 V-0 rating with LOI value of 33.0%.The PLA/IFR/MXene composites perform an obvious reduction in peak of heat release rate(HRR)in cone calorimeter tests(CCTs).Furthermore,the carbon residues after CCTs were characterized by scanning electron microscope(SEM),laser Raman spectroscopy(LRS),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).It is demonstrated that both the titanium composition of the MXene structure and the characteristics of the two-dimensional material enhance the PLA/IFR/MXene composite materials’ability to produce a dense barrier layer to resist burnout during thermal degradation.展开更多
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.Howeve...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~2.3and~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℃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.展开更多
A halogen-free flame-retardant (hydroquinone bis (N,N’-diarylphosphoramidate),4N-HDP) containing phosphorus-nitrogen was synthesized.Its structure was characterized by infrared spectroscopy (IR),nuclear magnetic reso...A halogen-free flame-retardant (hydroquinone bis (N,N’-diarylphosphoramidate),4N-HDP) containing phosphorus-nitrogen was synthesized.Its structure was characterized by infrared spectroscopy (IR),nuclear magnetic resonance (^(1)H-NMR and^(31)P-NMR).Thermogravimetric analysis (TG),limiting oxygen index (LOI),UL-94 vertical burning test (UL-94),thermogravimetric-infrared instrument (TG-IR) and scanning electron microscopy (SEM) were used to compare the flame-retarding performance and mechanism of hydroquinone bis (diphenyl phosphate) (HDP) and 4N-HDP.TG,IR and TG-IR were used for comparative analysis,indicating that both HDP and 4N-HDP are flame-retardants,and the gas phase and condensed phase act synergistically.In the pyrolysis process,it is divided into two steps:the first step is the breakage of large molecules to small molecules;the second step is the gasification and carbonization of small molecules,and eventually produces phosphate ester and non-flammable gases.Through the comparison of various results,it could be found that 4N-HDP has better flame-retarding performance compared to HDP in the composite with polycarbonate (PC).展开更多
For solid polymer electrolytes(SPEs),improving their mechanical and electrochemical properties is the key to obtaining batteries with higher safety and higher energy density.Herein,a novel synergistic strategy propose...For solid polymer electrolytes(SPEs),improving their mechanical and electrochemical properties is the key to obtaining batteries with higher safety and higher energy density.Herein,a novel synergistic strategy proposed is preparing a 3D flame-retardant skeleton(3DPA)and adding nano-multifunctional fillers(Li-ILs@ZIF-8).In addition to providing mechanical support for the polyethylene oxide(PEO)matrix,3DPA also has further contributed to the system’s flame retardancy and further improved the safety.Simultaneously,the electrochemical performance is fully guaranteed by rigid Li-ILs@ZIF-8,which provides fast migration channels forLi^(+),reduces the crystallinity of PEO and effectively inhibits lithium dendrites.The limiting oxygen index of the optimal sample(PL3Z/PA)is as high as 20.5%,and the ionic conductivity reaches 2.89×10^(-4) and 0.91×10^(-3) S cm^(-1) at 25 and 55°C,respectively.The assembled Li|PL3Z/PA|Li battery can be cycled stably for more than 1000 h at a current density of 0.1 m A cm^(-2) without short circuit being pierced by lithium dendrites.The specific capacity of the LFP|PL3Z/PA|Li battery was 160.5 m Ah g^(-1) under a current density of 0.5 C,and the capacity retention rate was 90.0%after 300 cycles.展开更多
Twenty tests were conducted to investigate the efficiency of the intumescent coating designed to protect steel plate at the elevated temperature, by means of electrical furnace. And the factors of the initial thicknes...Twenty tests were conducted to investigate the efficiency of the intumescent coating designed to protect steel plate at the elevated temperature, by means of electrical furnace. And the factors of the initial thickness of coating and temperature of electrical furnace were considered. The high temperature response behavior of the intumescent coating was observed. And the expansion form of ultrathin intumescent coating and the temperature of the steel plate(TS) were obtained. Besides, the heat flux from expansion layer to steel plate versus time was analyzed in order to evaluate the heat transfer effect of intumescent coating on steel plate. The experimental results show that the response behaviors of the coating subjected to fire could be divided into four phases: stabilization phase, foaming expansion phase, carbonization-consumption phase and inorganic layer phase. And the net heat flux to the steel plate decreased observably in the foaming expansion phase, while the surplus white inorganic substance, which is the residue of the intumesced char layer in the inorganic layer phase under the condition of the temperature of the electrical furnace(TEF) beyond 700 °C over 1 h, has little effect on fire protection for the steel plate.展开更多
The efficiency of different intumescent flame-retardant (IFR) formulations designed to improve the flame resistance of fluoroelastomer ( FKM ) composites was studied. The proportion of ammonium polyphosphate (APP...The efficiency of different intumescent flame-retardant (IFR) formulations designed to improve the flame resistance of fluoroelastomer ( FKM ) composites was studied. The proportion of ammonium polyphosphate (APP) with charring-foaming agent (CFA) in IFR systems, and the addi- tion of synergists zinc borate (ZB) and ketonealdehyde resin ( KR120 ) were investigated to show their effect on flame resistance of FKM. According to flame resistance tests, when the mass ratio of APP to CFA was 4:1 as well as the loadings of IFR, ZB, KR120 were 83 parts per hundred resin (phr), 13phr, 25phr, respectively, the FKM-KR120/IFR-ZB composites had good synergetic flame resistant effect. TGA data showed that IFR and synergists could obviously lower the maximum weight loss rate of FKM composites and effectively increase the char residue at high temperature. The morphological structures of the composites observed by scanning electron microscopy (SEM) demonstrated that the addition of ZB and KR120 could clearly reduce the cracks in char residue and make the char layer structure more integrated and compact.展开更多
Although polyimide fibers are excellent intrinsic flame-retardant fibers, their price is so high that they are rarely used in clothing. To expand their application, the polyimide fibers were blended with flame-retarda...Although polyimide fibers are excellent intrinsic flame-retardant fibers, their price is so high that they are rarely used in clothing. To expand their application, the polyimide fibers were blended with flame-retardant viscose fibers at a ratio of 30∶70, and the blended yarns were woven with flame-retardant polyester filaments. Fabrics with different parameters, including fabric weaves, warp yarn densities, and fabric layers, were designed, and the effects of those fabric parameters on mechanical properties and flame-retardant properties were tested and analyzed. The results show that the tearing load of the fabrics is affected by fabric weaves, warp yarn densities, and fabric layers, and the tearing load of the weft mountain weave fabric and the twill weave fabric is higher than that of the plain weave fabric. The bursting load of the fabric increases with the increase of warp yarn densities and layers. Among the tested fabric samples, the triple-layer twill fabric has the best flame-retardant performance, which meets the standard of flame-retardant protective fabric Grade B1 level. The research of this paper would provide guidance for the development and production of polyimide blended fabrics.展开更多
Some organoboron compounds as flame-retardants for fiber materials were prepared.Flame-retarding properties of these compounds determined by the Oxygen-Index Method weregood.These new compounds were characterized by I...Some organoboron compounds as flame-retardants for fiber materials were prepared.Flame-retarding properties of these compounds determined by the Oxygen-Index Method weregood.These new compounds were characterized by IR,~1H NMR spectrum and elementalanalysis.展开更多
Flame-retardant polymer electrolytes(FRSPEs)are attractive due to their potential for fundamentally settling the safety issues of liquid electrolytes.However,the current FRSPEs have introduced large quantity of flame-...Flame-retardant polymer electrolytes(FRSPEs)are attractive due to their potential for fundamentally settling the safety issues of liquid electrolytes.However,the current FRSPEs have introduced large quantity of flame-retardant composition which cannot conduct lithium ions,thus decreasing the Li-ion conductivity.Here,we synthesize a novel liquid monomer 2-((bis((2-oxo-1,3-dioxolan-4-yl)methoxy)phosphoryl)oxy)ethyl acrylate(BDPA)for preparing FRSPE by in-situ polymerization,in which PBDPA polymer can not only conduct lithium ions,but also prevent burning.The prepared FRSPE demonstrated outstanding flame-retardant property,favorable lithium-ion conductivity of 5.65×10^(-4) S cm^(-1) at ambient temperature,and a wide electrochemical window up to 4.5 V.Moreover,the Li/in-situ FRSPE/S@pPAN cell exhibited favorable electrochemical performances.We believe that this work provides an effective strategy for establishing high-performance fireproof quasi-solid-state battery system.展开更多
基金Funded by the Program for New Century Excellent Talents in University of Ministry of Education of China(NCET-12-0912)。
文摘To improve the flame resistance of polypropylene(PP)/carbon fiber(CF)composite materials,triazine char-forming agent(TCA)was compounded with ammonium polyphosphate(APP)or modified APP(CS-APP)in a 2:1 ratio to prepare intumescent flame retardant(IFR)and the modified intumescent flame retardant(CS-IFR)in this paper.Flame retardancy and thermal degradation behaviors of the composites modified by IFR and CS-IFR were characterized by Fourier Transform Infrared(FTIR),contact angle measurement,oxygen index(OI),vertical burning tests(UL-94),thermogravimetric analyer(TGA),and thermogravimetric analyzer coupled with Fourier transform infrared(TG-FTIR).It was found that 25.0 phr of IFR and 24.0 phr of CS-IFR could improve the LOI value of PP/CF composites to 28.3%and 28.9%,respectively.At the same time,a UL-94 V-0 rating was achieved.The experimental results show that the IFR and CS-IFR prepared could effectively improve the flame retardancy and thermostability of PP/CF composites,and they would greatly expand the application range of PP/CF composite materials.
基金supported by the National Research Foundation of Korea(NRF-2021R1A2C1008272)supported by the Institute of Information&communications Technology Planning&Evaluation(IITP)grant funded by the Korean government(MSIT)(No.2021-0-00259,Development of a Fast Wireless Charging System for Portable Terminals with improved heat dissipation and shielding performance)supported by the Applied Basic Research Program of Changzhou City(CJ20220030).
文摘Lithium-sulfur(Li-S)batteries are one of the most promising modern-day energy supply systems because of their high theoretical energy density and low cost.However,the development of high-energy density Li-S batteries with high loading of flammable sulfur faces the challenges of electrochemical performance degradation owing to the shuttle effect and safety issues related to fire or explosion accidents.In this work,we report a three-dimensional(3D)conductive nitrogen-doped carbon foam supported electrostatic self-assembled MXene-ammonium polyphosphate(NCF-MXene-APP)layer as a heat-resistant,thermally-insulated,flame-retardant,and freestanding host for Li-S batteries with a facile and costeffective synthesis method.Consequently,through the use of NCF-MXene-APP hosts that strongly anchor polysulfides,the Li-S batteries demonstrate outstanding electrochemical properties,including a high initial discharge capacity of 1191.6 mA h g^(-1),excellent rate capacity of 755.0 mA h g^(-1)at 1 C,and long-term cycling stability with an extremely low-capacity decay rate of 0.12%per cycle at 2 C.More importantly,these batteries can continue to operate reliably under high temperature or flame attack conditions.Thus,this study provides valuable insights into the design of safe high-performance Li-S batteries.
基金funding from the National Natural Science Foundation of China(No.22268025)China Postdoctoral Science Foundation(NO.2022MD713757)+2 种基金Yunnan Provincial Postdoctoral Science Foundation(NO.34Y2022)Yunnan Province Joint Special Project for Enterprise Fundamental Research and Applied Basic Research(No.202101BC070001-016)Guangdong Basic and Applied Basic Research Foundation(No.2023A1515011985).
文摘Phase change materials(PCMs)offer a promising solution to address the challenges posed by intermittency and fluctuations in solar thermal utilization.However,for organic solid-liquid PCMs,issues such as leakage,low thermal conductivity,lack of efficient solar-thermal media,and flamma-bility have constrained their broad applications.Herein,we present an innova-tive class of versatile composite phase change materials(CPCMs)developed through a facile and environmentally friendly synthesis approach,leveraging the inherent anisotropy and unidirectional porosity of wood aerogel(nanowood)to support polyethylene glycol(PEG).The wood modification process involves the incorporation of phytic acid(PA)and MXene hybrid structure through an evaporation-induced assembly method,which could impart non-leaking PEG filling while concurrently facilitating thermal conduction,light absorption,and flame-retardant.Consequently,the as-prepared wood-based CPCMs showcase enhanced thermal conductivity(0.82 W m^(-1)K^(-1),about 4.6 times than PEG)as well as high latent heat of 135.5 kJ kg^(-1)(91.5%encapsula-tion)with thermal durability and stability throughout at least 200 heating and cooling cycles,featuring dramatic solar-thermal conversion efficiency up to 98.58%.In addition,with the synergistic effect of phytic acid and MXene,the flame-retardant performance of the CPCMs has been significantly enhanced,showing a self-extinguishing behavior.Moreover,the excellent electromagnetic shielding of 44.45 dB was endowed to the CPCMs,relieving contemporary health hazards associated with electromagnetic waves.Overall,we capitalize on the exquisite wood cell structure with unidirectional transport inherent in the development of multifunctional CPCMs,showcasing the operational principle through a proof-of-concept prototype system.
基金supported by the National Natural Science Foundation of China (51773134, U19A2095)the Sichuan Science and Technology Program (2019YFH0112)+2 种基金the Fundamental Research Funds for the Central UniversitiesInstitutional Research Fund from Sichuan University (2021SCUNL201)the 111 Project (B20001)。
文摘Preparing both safe and high-performance lithium-ion batteries(LIBs) based on commonly used commercial electrolytes is highly desirable,yet challenging.To overcome the poor compatibility of conventional small-molecular flame-retardants as electrolyte additives for safe LIBs with graphite anodes,in this study,we propose and design a novel low-cost flame-retardant oligomer that achieves an accurate and complete reconciliation of fire safety and electrochemical performance in LIBs.Owing to the integration of phosphonate units and polyethylene glycol(PEG) chains,this oligomer,which is a phosphonatecontaining PEG-based oligomer(PPO),not only endows commercial electrolytes with excellent flame retardancy but also helps stabilize the electrodes and Li-ion migration.Specifically,adding 15 wt% of PPO can reduce 70% of the self-extinguishing time and 54% of total heat release for commercial electrolytes.Moreover,LiFePO_(4)/lithium and graphite/lithium cells as well as LiFePO_(4)/graphite pouch full cells exhibit good long-term cycling stability.
基金the National Natural Science Foundation of China (No.51673059)the Science and Technology Planning Project of Henan Province (No. 212102210636)the Opening Project of Jiangxi Province Key Laboratory of Polymer Micro/Nano Manufacturing and Devices (East China University of Technology)。
文摘Polyamide 6 (PA6) was employed as a charring agent of intumescent flame retardant (IFR) to improve the flame retardancy of ethylene-vinyl acetate copolymer (EVA). Different processing procedures were used to regulate the localization of IFR in the EVA matrix. Localizations in which IFR was dispersed in the PA6phase or in the EVA phase were prepared. The effect of the localization of IFR on the flame retardancy of EVA was investigated. The limited oxygen index (LOI), vertical burning (UL 94) and cone calorimeter test (CCT)showed that the localization of IFR in the EVA matrix exhibited a remarkable influence on the flame retardancy.Compared with EVA/IFR, a weak improvement in the flame retardancy was observed in the EVA/PA6/IFR blend withthe localization of IFR in the PA6 phase. When IFR was regulated from the PA6 phase to the EVA matrix,a remarkable increase in the flame retardancy was exhibited. The LOI was increased from 27.8%to 32.7%, and the UL 94 vertical rating was increased from V-2 to V-0. Moreover, an approximately 41.36%decrease in the peak heat release rate was exhibited. A continuous and compact intumescent charring layer that formed in the blends with the localization of IFR in the EVA matrix should be responsible for its excellent flame retardancy.
文摘A novel phosphorus-nitrogen containing intumescent flame retardant (P-N IFR) was prepared via the reaction of dichlor-opentate with N-methylaniline. The structure of the product was confirmed by ^1H NMR, ^31p NMR, MS and IR. TGA analysis showed it has effective thermal stability.
基金This work was supported by a grant from the Knowledge-Creating Engineering Fund of the Chinese Academy of Science.
文摘The synergistic effects of silicotungstic acid (SiW12) as a catalyst in the phosphorus-nitrogen compounds AM-based intumescent flame-retardant (IFR) polypropylene (PP) were studied using the limiting oxygen index (LOI), the UL-94 test, thermogravimetric analysis (TGA), real time Fourier transform infrared (FTIR), laser Raman spectroscopy (LRS). The LOI data show that SiW12 added to PP/IFR systems has a synergistic FR effect with an IFR additive named AM. The TGA data show that SiW12 apparently increases the thermal stability of the PP/IFR systems at high temperature (T > 500degreesC). The FTIR results provide the positive evidence that IFR can improve the thermal stability of PP and SiW12 can induce a higher rate of formation of phosphoric acid and its derivatives. The LRS measurements provide useful information on the carbonaceous microstructures. In short, a suitable amount of SiW12 (1.5 wt%) exerts synergistic effects with the IFR by increasing the LOI value and the thermal stability at high temperature and promoting the formation of charred structures on the burning PP surface.
文摘Three novel triazine-based charring-foaming agents (M2-CFA,M4-CFA,and M6-CFA) were synthesized successfully with only water as the solvent and were characterized by FT-IR and thermal gravimetric analysis (TGA).These three charring-foaming agents and the byproduct 944-by were employed to study the effectiveness of the novel intumescent flame retardant dopant on the fire retardancy of polypropylene (PP) investigated through UL-94 and limiting oxygen index (LOI) tests.TGA results showed that the M4-CFA presented good char formation ability (char residue: 26.8% at 700 ℃).It was found that the sample with a 2/1 mass ratio of APP to M4-CFA exhibited the best flame retardancy among all the PP composites: 35.5% LOI and a V-0 rating of UL-94.Additionally,the microstructure and morphology of char residues were further studied by XRD,Raman spectroscopy and SEM.
基金Funded by the Defense Preresearch Project of the Eleventh-Five-Year-Plan of China (No. 51312040404)
文摘Flame-retardant mechanism of magnesium oxychloride (M OC) in EP was in-vestigated by limiting oxygen index (LOI), XRD, SEM, TG-DTG and DSC. The results show that MOC performed well as an inorganic flame-retardant in EP. When the content of MOC is 50%, the LOI of EP reaches 29.6% and mass of residual char reaches 9.6%. The flame retarde mechanism of MOC is due to the synergies of diluting, cooling, catalyzing char forming and obstructing effects.
基金support from the National Natural Science Foundation of China(Grant Nos.21908031 and 51903092)the China Postdoctoral Science Foundation funded project(Grant No.2019M652884)support from Guangdong Special Support Program(Grant No.2017TX04N371)。
文摘The effect of Ti3C2 MXene nanosheets on the intumescent flame retardant(IFR)poly(lactic acid)(PLA)composites was investigated among a series of PLA/IFR/MXene,which were prepared by melt blending 0-2.0 wt%MXene,10.0 wt%-12.0 wt%IFR and PLA together.The results of limiting oxygen index(LOI)and vertical burning(UL-94)discover that the combination of 0.5 wt%MXene and 11.5 wt%IFR synergistically improves the fire safety of PLA to reach UL-94 V-0 rating with LOI value of 33.0%.The PLA/IFR/MXene composites perform an obvious reduction in peak of heat release rate(HRR)in cone calorimeter tests(CCTs).Furthermore,the carbon residues after CCTs were characterized by scanning electron microscope(SEM),laser Raman spectroscopy(LRS),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).It is demonstrated that both the titanium composition of the MXene structure and the characteristics of the two-dimensional material enhance the PLA/IFR/MXene composite materials’ability to produce a dense barrier layer to resist burnout during thermal degradation.
基金The research work was financially supported by the Australian Research Council(Nos.DE190101176,FT190100188,DP190102992,IC170100032)the National Natural Science Foundation of China(51973047)+2 种基金the Project for the Science and Technology Program of Hangzhou(20201203B136,20201203B134)the International Collaboration Programs of Guangdong Province(2020A0505100010)Open access funding provided by Shanghai Jiao Tong University
文摘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~2.3and~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℃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.
基金Funded by the National Key Research and Development Program of China(No.2016YFD0200404)the Sichuan Science and Technology Program(No.2018RZ0145)the National“Double First-Rate”Strategic Plan of Sichuan University,China(No.2030704401004)。
文摘A halogen-free flame-retardant (hydroquinone bis (N,N’-diarylphosphoramidate),4N-HDP) containing phosphorus-nitrogen was synthesized.Its structure was characterized by infrared spectroscopy (IR),nuclear magnetic resonance (^(1)H-NMR and^(31)P-NMR).Thermogravimetric analysis (TG),limiting oxygen index (LOI),UL-94 vertical burning test (UL-94),thermogravimetric-infrared instrument (TG-IR) and scanning electron microscopy (SEM) were used to compare the flame-retarding performance and mechanism of hydroquinone bis (diphenyl phosphate) (HDP) and 4N-HDP.TG,IR and TG-IR were used for comparative analysis,indicating that both HDP and 4N-HDP are flame-retardants,and the gas phase and condensed phase act synergistically.In the pyrolysis process,it is divided into two steps:the first step is the breakage of large molecules to small molecules;the second step is the gasification and carbonization of small molecules,and eventually produces phosphate ester and non-flammable gases.Through the comparison of various results,it could be found that 4N-HDP has better flame-retarding performance compared to HDP in the composite with polycarbonate (PC).
基金supported by the National Key Research and Development Program of China(Grant No.2017YFA0204600)the National Natural Science Foundation of China(Grant No.5210021666)the Key R&D and Promotion Projects of Henan Province(Grant No.212102310016)。
文摘For solid polymer electrolytes(SPEs),improving their mechanical and electrochemical properties is the key to obtaining batteries with higher safety and higher energy density.Herein,a novel synergistic strategy proposed is preparing a 3D flame-retardant skeleton(3DPA)and adding nano-multifunctional fillers(Li-ILs@ZIF-8).In addition to providing mechanical support for the polyethylene oxide(PEO)matrix,3DPA also has further contributed to the system’s flame retardancy and further improved the safety.Simultaneously,the electrochemical performance is fully guaranteed by rigid Li-ILs@ZIF-8,which provides fast migration channels forLi^(+),reduces the crystallinity of PEO and effectively inhibits lithium dendrites.The limiting oxygen index of the optimal sample(PL3Z/PA)is as high as 20.5%,and the ionic conductivity reaches 2.89×10^(-4) and 0.91×10^(-3) S cm^(-1) at 25 and 55°C,respectively.The assembled Li|PL3Z/PA|Li battery can be cycled stably for more than 1000 h at a current density of 0.1 m A cm^(-2) without short circuit being pierced by lithium dendrites.The specific capacity of the LFP|PL3Z/PA|Li battery was 160.5 m Ah g^(-1) under a current density of 0.5 C,and the capacity retention rate was 90.0%after 300 cycles.
基金Project(12JJ2033)supported by the Hunan Provincial Natural Science Foundation of ChinaProject(KFK2014ZD02)supported by the Key Laboratory of Building Fire Protection Engineering and Technology of MPS,ChinaProject supported by the Fundamental Research Funds for the Central Universities of Central South University,China
文摘Twenty tests were conducted to investigate the efficiency of the intumescent coating designed to protect steel plate at the elevated temperature, by means of electrical furnace. And the factors of the initial thickness of coating and temperature of electrical furnace were considered. The high temperature response behavior of the intumescent coating was observed. And the expansion form of ultrathin intumescent coating and the temperature of the steel plate(TS) were obtained. Besides, the heat flux from expansion layer to steel plate versus time was analyzed in order to evaluate the heat transfer effect of intumescent coating on steel plate. The experimental results show that the response behaviors of the coating subjected to fire could be divided into four phases: stabilization phase, foaming expansion phase, carbonization-consumption phase and inorganic layer phase. And the net heat flux to the steel plate decreased observably in the foaming expansion phase, while the surplus white inorganic substance, which is the residue of the intumesced char layer in the inorganic layer phase under the condition of the temperature of the electrical furnace(TEF) beyond 700 °C over 1 h, has little effect on fire protection for the steel plate.
基金Supported by the National Key Technology R & D Program (2006BAE03B05-2)
文摘The efficiency of different intumescent flame-retardant (IFR) formulations designed to improve the flame resistance of fluoroelastomer ( FKM ) composites was studied. The proportion of ammonium polyphosphate (APP) with charring-foaming agent (CFA) in IFR systems, and the addi- tion of synergists zinc borate (ZB) and ketonealdehyde resin ( KR120 ) were investigated to show their effect on flame resistance of FKM. According to flame resistance tests, when the mass ratio of APP to CFA was 4:1 as well as the loadings of IFR, ZB, KR120 were 83 parts per hundred resin (phr), 13phr, 25phr, respectively, the FKM-KR120/IFR-ZB composites had good synergetic flame resistant effect. TGA data showed that IFR and synergists could obviously lower the maximum weight loss rate of FKM composites and effectively increase the char residue at high temperature. The morphological structures of the composites observed by scanning electron microscopy (SEM) demonstrated that the addition of ZB and KR120 could clearly reduce the cracks in char residue and make the char layer structure more integrated and compact.
基金National Natural Science Foundation of China (No.11802161)Natural Science Foundation of Fujian Province,China (No.2020J05160)Startup Foundation for Doctors of Quanzhou Normal University,China (No.H18012)。
文摘Although polyimide fibers are excellent intrinsic flame-retardant fibers, their price is so high that they are rarely used in clothing. To expand their application, the polyimide fibers were blended with flame-retardant viscose fibers at a ratio of 30∶70, and the blended yarns were woven with flame-retardant polyester filaments. Fabrics with different parameters, including fabric weaves, warp yarn densities, and fabric layers, were designed, and the effects of those fabric parameters on mechanical properties and flame-retardant properties were tested and analyzed. The results show that the tearing load of the fabrics is affected by fabric weaves, warp yarn densities, and fabric layers, and the tearing load of the weft mountain weave fabric and the twill weave fabric is higher than that of the plain weave fabric. The bursting load of the fabric increases with the increase of warp yarn densities and layers. Among the tested fabric samples, the triple-layer twill fabric has the best flame-retardant performance, which meets the standard of flame-retardant protective fabric Grade B1 level. The research of this paper would provide guidance for the development and production of polyimide blended fabrics.
文摘Some organoboron compounds as flame-retardants for fiber materials were prepared.Flame-retarding properties of these compounds determined by the Oxygen-Index Method weregood.These new compounds were characterized by IR,~1H NMR spectrum and elementalanalysis.
基金financially supported by the National Natural Science Foundation of China(Nos.21773154 and U1705255)。
文摘Flame-retardant polymer electrolytes(FRSPEs)are attractive due to their potential for fundamentally settling the safety issues of liquid electrolytes.However,the current FRSPEs have introduced large quantity of flame-retardant composition which cannot conduct lithium ions,thus decreasing the Li-ion conductivity.Here,we synthesize a novel liquid monomer 2-((bis((2-oxo-1,3-dioxolan-4-yl)methoxy)phosphoryl)oxy)ethyl acrylate(BDPA)for preparing FRSPE by in-situ polymerization,in which PBDPA polymer can not only conduct lithium ions,but also prevent burning.The prepared FRSPE demonstrated outstanding flame-retardant property,favorable lithium-ion conductivity of 5.65×10^(-4) S cm^(-1) at ambient temperature,and a wide electrochemical window up to 4.5 V.Moreover,the Li/in-situ FRSPE/S@pPAN cell exhibited favorable electrochemical performances.We believe that this work provides an effective strategy for establishing high-performance fireproof quasi-solid-state battery system.