The theory and approach of the surface modified of asphalt fire-retardant with silane coupling agent were introduced. The optimum silane dosage was determined, and the structure and properties of the asphalt fire-reta...The theory and approach of the surface modified of asphalt fire-retardant with silane coupling agent were introduced. The optimum silane dosage was determined, and the structure and properties of the asphalt fire-retardant before and after the surface modification were characterized by infrared spectrum and thermo gravimetric analysis. The dispersion effect of asphalt flre-retardant was studied. The influence of the surface modification on the hydrophilicity and lipophilicity of the asphalt fire-retardant was analyzed. The experimental results showed that there were physical and chemical interactions between the silane coupling agent and the asphalt fire-retardant, which reduced the surface polarity of the asphalt fire retardant. The optimum silane coupling agent dosage was 0.95% of the asphalt fire retardant. The surface modification improved the thermal stability, dispersibility and lipophilicity of the asphalt fire retardant, which enhanced the compatibility between asphalt fire retardant and asphalt.展开更多
This study was to develop the flame retardant (FR) protective clothing which had multifunction such anti-bacterial, UV cut, FR function with water repellent and water vapor permeable laminating textiles for industrial...This study was to develop the flame retardant (FR) protective clothing which had multifunction such anti-bacterial, UV cut, FR function with water repellent and water vapor permeable laminating textiles for industrial workers. First of all, the FR yarn and FR textiles were developed for this purpose. Second, the comparison analysis between the halogen laminating textiles and halogen-free laminating textiles were tested to figure out the eco-friendly laminating method. Third, the flame retardant ability was compared the halogen laminated textiles to halogen-free laminated textiles. LOI, UV protection ratio, antibiosis after 50 laundry test, water proof pressure, and moisture permeability of developed textiles were tested. GC-HR-TOF-MS was used for analysis of laminating film (halogen and halogen-free). 4.1 wt% TiO2 yarn showed antibacterial function (Pneumococcus & Staphylococcus aureus: 99.9%), UV Protection (UVA: 90.8, UVB: 92.1), and LOI (33.6). The chosen optimal compounding ratio for PU compound of HRF and HFFR were as followed: PU resin 58.3%, DMF (Dimethyl formamide, δ = 12.2) 8.3%, MEK (Methylethylketone) 8.3% and FR (flame retardants) 25.0%. Binder for laminating should not be included over 10% of FRs because of adhesion between textiles and FR laminating film. There were detected phosphorus compounds in the textiles treated by halogenated type flame retardants and halogenated-free type flame retardants. There were not any detected harmful compounds from all textile samples.展开更多
Nanocrystalline Mg-Al layered double hydroxides with the particle size being 10—40 nm were firstly prepared by the technology of the microwave-crystallization and the vari- able-speed addition of the alkali. The obta...Nanocrystalline Mg-Al layered double hydroxides with the particle size being 10—40 nm were firstly prepared by the technology of the microwave-crystallization and the vari- able-speed addition of the alkali. The obtained samples were characterized by TEM and XRD. The roles of the microwave and addition rate of the alkali were also discussed in the present work. The thermal decomposition activation energy of the nano-LDHs was calculated according to their TG, DTG and DSC curves by the Ozawa method. The results showed that the thermal decom- position of the nano-LDHs had four steps. Thereby the decomposition model of the nano-LDHs was supposed according to the analysis of their thermal decomposition. After PS, ABS, HDPE and PVC were filled with the nano-LDHs, their LOI values could be increased up to 28, 27, 26 and 33, respectively. When the fire-retardant coating contained 1.9% of the nano-LDHs that was 0.27 times the dosage of the conventional TiO2, its fire endurance time reached 32.75min that was 7.05 min longer than that of the best coating containing TiO2 according to the model big-panel combustion test method.展开更多
Driven by global environmental concerns,many efforts have been made to develop halogen-free flame retardants for rigid polyurethane foam(RPUF).These environmentally benign flame retardants are mainly divided into(i)re...Driven by global environmental concerns,many efforts have been made to develop halogen-free flame retardants for rigid polyurethane foam(RPUF).These environmentally benign flame retardants are mainly divided into(i)reactive,(ii)additive,and(iii)coating types.The last decade has witnessed great progress of these three strategies,which enhance the fire safety of RPUF and maintain even improve the thermal insulation properties.This comprehensive review focuses on the up-to-date design of the reactive,additive,and coating flame retardants,and their effects on flame retardancy and thermal conductivity of RPUF.Moreover,the practical applications of the as-prepared flame-retardant RPUFs are highlighted.Finally,key challenges associated with these three kinds of flame retardants are discussed and future research opportunities are also proposed.展开更多
To study the effects of different proportions of aluminum hydroxide and expandable graphite (EG) composites on flame retardation, sealing, mechanical, electrical and other properties of RTV- 1, aluminum hydroxide/ex...To study the effects of different proportions of aluminum hydroxide and expandable graphite (EG) composites on flame retardation, sealing, mechanical, electrical and other properties of RTV- 1, aluminum hydroxide/expandable graphite (ATH/EG) and silicone rubber composites were prepared by the compression molding method. The experimental results show that heat resistance improves with the increase of proportion of EG. Although the resistance coefficient changes, the composite materials still keep good electrical insulating property. Moreover, oxygen index and expansion index rise first then fall. When ATH/EG is 1:1, the oxygen index reaches the highest; the mechanical property of the silicone rubber is not affected under various environments such as acid, alkali, oily, artificial sea water environments, etc.展开更多
A series of new halogen-free dicationic ionic liquids(ILs)with different alkyl chain lengths were prepared,and the relationship between the alkyl chain length,physicochemical and tribological properties of ILs,and the...A series of new halogen-free dicationic ionic liquids(ILs)with different alkyl chain lengths were prepared,and the relationship between the alkyl chain length,physicochemical and tribological properties of ILs,and their role as neat lubricant for steel–steel friction pairs,was investigated.Evaluation of stability during hydrolysis and copper strip corrosion test results show that synthetic ILs are stable and not corrosive to metal contacts,due to the halogen-free anions.The friction and wear test results indicate that ILs with long alkyl chains have excellent friction-reducing and anti-wear properties,especially at high temperatures.Based on the surface three-dimensional(3D)profiles,electrical contact resistance,scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),and the X-ray photoelectron spectrometry(XPS)analysis of the worn surfaces of steel discs,we can conclude that the efficiency of ILs is due to the formation of high quality tribofilms that consist of both tribochemical reaction and ordered absorption films.展开更多
Poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt(4,4′-(N-(4-butylphenyl))](TFB),one of the most popular and widely used hole-transport layer(HTL)materials,has been successfully applied in high performance spin-coated quantum...Poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt(4,4′-(N-(4-butylphenyl))](TFB),one of the most popular and widely used hole-transport layer(HTL)materials,has been successfully applied in high performance spin-coated quantum dots-based light-emitting diodes(QLEDs)due to its suitable energy level and high mobility.However,there are still many challenging issues in inkjet-printed QLED devices when using TFB as HTL.TFB normally suffers from the interlayer mixing and erosion,and low surface energy against the good film formation.Here,a novel environment-friendly binary solvent system was established for formulating quantum dot(QD)inks,which is based on mixing halogen-free alkane solvents of decalin and n-tridecane.The optimum volume ratio for the mixture of decalin and n-tridecane was found to be 7:3,at which a stable ink jetting flow and coffee-ring free QD films could be formed.To research the influence of substrate surface on the formation of inkjet-printed QD films,TFB was annealed at different temperatures,and the optimum annealing temperature was found to enable high quality inkjet-printed QD film.Inkjet-printed red QLED was ultimately manufactured.A maximum 18.3%of external quantum efficiency(EQE)was achieved,reaching 93%of the spin-coated QLED,which is the best reported high efficiency inkjet-printed red QLEDs to date.In addition,the inkjet-printed QLED achieved similar T75 operational lifetime(27 h)as compared to the spin-coated reference QLED(28 h)at 2,000 cd·m−2.This work demonstrated that the novel orthogonal halogen-free alkane co-solvents can improve the interfacial contact and facilitate high-performance inkjet printing QLEDs with high EQE and stability.展开更多
The atom-economical cycloaddition of CO_(2) with epoxides to synthesize cyclic carbonates is a promising route for valuable utilization of CO_(2).Halogenide such as alkali metal halides and quaternary ammonium salt ha...The atom-economical cycloaddition of CO_(2) with epoxides to synthesize cyclic carbonates is a promising route for valuable utilization of CO_(2).Halogenide such as alkali metal halides and quaternary ammonium salt have been developed as the efficient catalysts.However,the spilled halogen causes equipment corrosion and affects the product purity.To address these concerns,the halogen-free cycloaddition of CO_(2) with epoxides has always been desired.In this review,we systematically discussed the halogen-free catalysis for cycloaddition of CO_(2) with epoxides from the mechanistic insights,aiming to promote the development of efficient halogen-free catalysts.Two types of catalysts,i.e.,alternatives of halogen nucleophiles for epoxide activation,and bifunctional catalysts with Lewis acid-base sites for synergistic activation of CO_(2) and epoxides are summarized and emphasized.Specially,metal oxides as the potential halogen-free catalysts are highlighted due to their flexible acid-base sites for synergistic activation of CO_(2) and epoxides,facile preparation,and low cost.展开更多
The chemical transformation of CO2 and epoxides into cyclic carbonates has been receiving much attention and is one of the successful examples for CO2 utilization as carbon resource.Many catalysts containing halide an...The chemical transformation of CO2 and epoxides into cyclic carbonates has been receiving much attention and is one of the successful examples for CO2 utilization as carbon resource.Many catalysts containing halide anions have been explored and exhibit excellent catalytic activity.However,halogen salt is generally toxic and corrosive to reactors.From a green chemistry perspective,it is more attractive to develop a halogen-free catalyst with excellent performance.Herein,a review of recent research progress of halogen-free catalysts in the cycloaddition of CO2 and epoxide is presented.According to previous experimental and theoretical works,two possible strategies for achieving the halogen-free process were summarized.The relationship between catalytic activity and catalyst structure,the mechanism of CO2 activation should be both studied deeply combined with experimental results and DFT calculation,which can guide the design of new catalysts and realize halogen-free process under mild reaction conditions.展开更多
Polymer solar cells(PSCs)consisting of a polymer donor and a small molecular acceptor is a promising photovoltaic technology,whose device performance is determined by both polymer donor and small molecular acceptor.Ha...Polymer solar cells(PSCs)consisting of a polymer donor and a small molecular acceptor is a promising photovoltaic technology,whose device performance is determined by both polymer donor and small molecular acceptor.Halogen atoms such as fluorine or chlorine atoms were usually introduced onto the polymer donors to downshift the highest occupied molecular orbital(HOMO)energy levels and improve the open-circuit voltage(VOC)of the PSCs.However,the introduction of the halogen atoms especially fluorine atoms greatly complicates the polymer synthesis.Herein,we report the use of a structural simple and easily synthesized building block,3,4-dicyanothiophene(DCT),to construct a set of halogen-free polymer donors PBCNTx(x=25,50,75)via ternary random copolymerization.The introduction of DCT units not only simplified the synthesis,but also downshifted the HOMO energy levels of the polymers and improved the V_(OC) of PSCs effectively.Encouragingly,the PBCNT75 afforded a power conversion efficiency up to 15.7%with a V_(OC) of 0.83 V,which are among the top values for halogen-free polymer donors.This work shows that the introduction of DCT units is a simple yet effective strategy to construct halogen-free and low-cost polymer donors for high-performance PSCs.展开更多
Polystyrene(PS)is rich in plastic materials,but it produces a large amount of waste every year,causing a huge burden on the environment.Although PS plastic is the source of a common"white pollution"in daily ...Polystyrene(PS)is rich in plastic materials,but it produces a large amount of waste every year,causing a huge burden on the environment.Although PS plastic is the source of a common"white pollution"in daily life,it still has a high utilization value.At the same time,the flammability of PS material determines that it cannot be applicated in places where fire accidents occur frequently.As a result,its application has been greatly limited.In order to realize the efficient utilization of waste PS and broaden its scope of application,PS was modified by hyper-crosslinking in order to improve its fire-retardant performance.In this method,the PS solution with high purity was obtained by dissolving waste PS foam with 1,2-dichloroethane(DCE),and then the hyper-crosslinked polymer with high specific surface area was prepared by adding cross-linking agent formaldehyde dimethyl acetal(FDA)and a Lewis-acid catalyst ferric chloride(FeCl_(3)).Further studies showed that the effects of the amount of cross-linking agent FDA,catalyst FeCl_(3) and PS on the reaction products were different.In addition,compared the as-prepared fire-retardant materials with PS foam from the aspects of flame retardancy and thermal insulation,it can be concluded that the fire-retardant performance of the materials prepared by this method has been significantly enhanced.And it is proved that this method is feasible towards the preparation of a large number of fire-retardant composite materials by using a scale-up experiment.展开更多
For the first time,we employed the halogen-free deep eutectic solvent(DES)into the Knoevenagel condensation between aromatic aldehydes and active methylene compounds at room temperature.The DESs[3Im:PTSA]and[4Im:PTSA]...For the first time,we employed the halogen-free deep eutectic solvent(DES)into the Knoevenagel condensation between aromatic aldehydes and active methylene compounds at room temperature.The DESs[3Im:PTSA]and[4Im:PTSA]were prepared by imidazole(Im)and p-tol-uenesulfonic acid(PTSA),which were experimentally screened from a series of organic acids with imidazole.a,b-Unsaturated carbonyl compounds were obtained in good to excellent yields under solvent-free conditions with fast reaction rate.These two DESs can be reused for multiple times with no loss of catalytic activity.展开更多
Bisphenol A bis(diphenyl phosphate) oligomer(BDP) is prepared successfully from the reactants consisting of phosphorus oxyehloride (POCl3), bisphenol A and phenol with a Friedel-Crafts catalyst. The resultant pr...Bisphenol A bis(diphenyl phosphate) oligomer(BDP) is prepared successfully from the reactants consisting of phosphorus oxyehloride (POCl3), bisphenol A and phenol with a Friedel-Crafts catalyst. The resultant products were examined with thermtygravimetrie analysis (TGA) and high performance liquid chro- matography(HPLC). Thermogravimetry data shows that BDP decomposes at 375℃ when 5 % weight lost. Experiments results show that catalyst is preferably AICI3 and the amount of it is preferably 1% relative to bisphenol A by mole. POCl3/bisphenol A mole ratio is preferably about 5:1 to 6:1. Experiments unclosed that a seal apparatus is very important to the properties of product.展开更多
The consumption ofthermoset resins as building polymers is approximately over one million tone word wide. The thermoset resins are proven construction materials for the technical and highly demanding applications of t...The consumption ofthermoset resins as building polymers is approximately over one million tone word wide. The thermoset resins are proven construction materials for the technical and highly demanding applications of the transportation, electrical and building part industry. Heat stability, high thermal, low shrinkage, excellent mechanical properties are typical for their type of polymers. Above applications in addition to the mechanical properties also require good flame retardants of the materials. Undertaken activities refer to official draft, laws and legal recommendations in UE states. This paper presents positive effect of reduced flammability of thermoset resins (unsaturated polyester and epoxy resins) thanks to the use of nanocomposites containing multi-ingredient halogen-flee flame retardants which combine conventional phosphorus/nitrogen modifiers interacting with nanofillers (oMMT (organomodified montmorillonite), EG (expandable graphite), graphene, GO (graphene oxide), nSi (nanosilica)).展开更多
Due to their durability,versatility,and aesthetic value,wood and wood-based composites are widely used as building materials.The fact that these materials are flammable,however,raises a major worry since they might ca...Due to their durability,versatility,and aesthetic value,wood and wood-based composites are widely used as building materials.The fact that these materials are flammable,however,raises a major worry since they might cause fire hazards and significant loss of life and property.The article investigates the variables that affect fire performance as well as the various fire-retardant treatments and their mechanisms.The current developments and challenges in improving the fire performance of wood and wood-based composites treated with fire-retardant materials are summarized in this paper.Nanoparticles,organic chemicals,and densification are some recent developments in fire-retardant treatments that are also emphasized.Key points from the review are summarized,along with potential areas for further research and development.展开更多
The materials with thermal insulating and fre-retardant properties are highly demanded for architectures to improve the energy efficiency.The applications of conventional inorganic insulating materials such as silica ...The materials with thermal insulating and fre-retardant properties are highly demanded for architectures to improve the energy efficiency.The applications of conventional inorganic insulating materials such as silica aerogels are restricted by their mechanical fragility and organic insulating materials are either easily ignitable or exhibit unsatisfactory thermal insulation performance.Here,we report an organic/inorganic composite aerogel with integrated double network structure,in which silica constituent homogeneously distribute in the anisotropic polyimide nanofber aerogel matrix and strong interfacial effect is formed between two components.The integrated binary network endows the polyimide/silica composite aerogels with outstanding compressibility and flexibility even with a high inorganic content of 60%,which can withstand 500 cyclic fatigue tests at a compressive strain of 50%in the radial direction.The resulting composite aerogel exhibits a combination of outstanding insulating performance with a low thermal conductivity(21.2 mW m^(-1)K^(-1))and excellent resistance to a 1200℃flame without disintegration.The high-performance polyimide/silica aerogels can decrease the risk brought by the collapse of reinforced concrete structures in a fre,demonstrating great potential as efficient building materials.展开更多
This paper investigated the fire-retardant mechanism of the nano-LDHs in the intumescent system by the temperature programmed oxidation (TPO). Researches were also conducted to explore the function of the nano-LDHs in...This paper investigated the fire-retardant mechanism of the nano-LDHs in the intumescent system by the temperature programmed oxidation (TPO). Researches were also conducted to explore the function of the nano-LDHs in the composite fire-retardant agents in air and nitrogen atmosphere, respectively. The results indicated that the nano-LDHs species were responsible for the catalytic oxidation of the rich-carbon compound in oxygen atmosphere. In addition, the nano-LDHs species and their calcinated products at high temperature could increase the carbonaceous residue-shield of the carbon-rich materials, improve the quality and the graphitization degree of the formed char-layer, and accelerate the intumescence and expansion of the melting carbon-rich materials to a certain degree under the oxygen-free condition, leading to the carbonization and expansion of the intumescent layer.展开更多
Carbon fibers(CFs)are widely used in various cutting-edge fields,such as aerospace,military,automobiles,and sports,owing to their unique combination of excellent mechanical properties,good thermal stability,and lightw...Carbon fibers(CFs)are widely used in various cutting-edge fields,such as aerospace,military,automobiles,and sports,owing to their unique combination of excellent mechanical properties,good thermal stability,and lightweight.However,their inherent super-black appearance makes it difficult to satisfy the aesthetic/fashion requirements of the colorful world,and the flammability of CFs severely limits their practical utilization in high-temperature and other extreme environments.Herein,we fabricated full-color tunable colored CFs on a large-scale via atomic layer deposition,based on the monolayer film interference strategy.CFs exhibited brilliant colors and excellent environmental durability in extreme environments,such as intense ultraviolet(UV)irradiation,accelerated laundering,friction,high-temperature,and low-temperature treatments.Colored CFs also exhibited excellent fire-retardant performance that could withstand alcohol-lamp flame burning for 60 min.Our work provides insights into an innovative material/structural design that can help achieve rapid development of the CF industry and global carbon neutrality/sustainability.展开更多
Though the power conversion efficiencies(PCEs) of organic solar cells(OSCs) have been boosted to 12%,the use of highly pollutive halogenated solvents as the processing solvent significantly hinders the mass produc...Though the power conversion efficiencies(PCEs) of organic solar cells(OSCs) have been boosted to 12%,the use of highly pollutive halogenated solvents as the processing solvent significantly hinders the mass production of OSCs. It is thus necessary to achieve high-efficiency OSCs by utilizing the halogen-free and environmentally-friendly solvents. Herein, we applied a halogen-free solvent system(oxylene/1-phenylnaphthalene, XY/PN) for fabricating fullerene-free OSCs, and a high PCE of 11.6% with a notable fill factor(FF) of 72% was achieved based on the PBDB-T:IT-M blend, which is among the top efficiencies of halogen-free solvent processed OSCs. In addition, the influence of different halogen-free solvent additives on the blend morphology and device performance metrics was studied by synchrotron-based tools and other complementary methods. Morphological results indicate the highly ordered molecular packing and highest average domain purity obtained in the blend films prepared by using XY/PN co-solvent are favorable for achieving increased FFs and thus higher PCEs in the devices.Moreover, a lower interaction parameter(χ) of the IT-M:PN pair provides a good explanation for the more favorable morphology and performance in devices with PN as the solvent additive, relative to those with diphenyl ether and Nmethylpyrrolidone. Our study demonstrates that carefully screening the non-halogenated solvent additive plays a vital role in realizing the efficient and environmentally-friendly solvent processed OSCs.展开更多
基金Funded by the National Natural Science Foundation of China(No.50978263)
文摘The theory and approach of the surface modified of asphalt fire-retardant with silane coupling agent were introduced. The optimum silane dosage was determined, and the structure and properties of the asphalt fire-retardant before and after the surface modification were characterized by infrared spectrum and thermo gravimetric analysis. The dispersion effect of asphalt flre-retardant was studied. The influence of the surface modification on the hydrophilicity and lipophilicity of the asphalt fire-retardant was analyzed. The experimental results showed that there were physical and chemical interactions between the silane coupling agent and the asphalt fire-retardant, which reduced the surface polarity of the asphalt fire retardant. The optimum silane coupling agent dosage was 0.95% of the asphalt fire retardant. The surface modification improved the thermal stability, dispersibility and lipophilicity of the asphalt fire retardant, which enhanced the compatibility between asphalt fire retardant and asphalt.
文摘This study was to develop the flame retardant (FR) protective clothing which had multifunction such anti-bacterial, UV cut, FR function with water repellent and water vapor permeable laminating textiles for industrial workers. First of all, the FR yarn and FR textiles were developed for this purpose. Second, the comparison analysis between the halogen laminating textiles and halogen-free laminating textiles were tested to figure out the eco-friendly laminating method. Third, the flame retardant ability was compared the halogen laminated textiles to halogen-free laminated textiles. LOI, UV protection ratio, antibiosis after 50 laundry test, water proof pressure, and moisture permeability of developed textiles were tested. GC-HR-TOF-MS was used for analysis of laminating film (halogen and halogen-free). 4.1 wt% TiO2 yarn showed antibacterial function (Pneumococcus & Staphylococcus aureus: 99.9%), UV Protection (UVA: 90.8, UVB: 92.1), and LOI (33.6). The chosen optimal compounding ratio for PU compound of HRF and HFFR were as followed: PU resin 58.3%, DMF (Dimethyl formamide, δ = 12.2) 8.3%, MEK (Methylethylketone) 8.3% and FR (flame retardants) 25.0%. Binder for laminating should not be included over 10% of FRs because of adhesion between textiles and FR laminating film. There were detected phosphorus compounds in the textiles treated by halogenated type flame retardants and halogenated-free type flame retardants. There were not any detected harmful compounds from all textile samples.
文摘Nanocrystalline Mg-Al layered double hydroxides with the particle size being 10—40 nm were firstly prepared by the technology of the microwave-crystallization and the vari- able-speed addition of the alkali. The obtained samples were characterized by TEM and XRD. The roles of the microwave and addition rate of the alkali were also discussed in the present work. The thermal decomposition activation energy of the nano-LDHs was calculated according to their TG, DTG and DSC curves by the Ozawa method. The results showed that the thermal decom- position of the nano-LDHs had four steps. Thereby the decomposition model of the nano-LDHs was supposed according to the analysis of their thermal decomposition. After PS, ABS, HDPE and PVC were filled with the nano-LDHs, their LOI values could be increased up to 28, 27, 26 and 33, respectively. When the fire-retardant coating contained 1.9% of the nano-LDHs that was 0.27 times the dosage of the conventional TiO2, its fire endurance time reached 32.75min that was 7.05 min longer than that of the best coating containing TiO2 according to the model big-panel combustion test method.
基金financially supported by the Australian Research Council(Nos.DP190102992,FT190100188)the National Natural Science Foundation of China(No.51873196)the Key Research and Development Projects of Zhejiang Province(No.2019C01098)。
文摘Driven by global environmental concerns,many efforts have been made to develop halogen-free flame retardants for rigid polyurethane foam(RPUF).These environmentally benign flame retardants are mainly divided into(i)reactive,(ii)additive,and(iii)coating types.The last decade has witnessed great progress of these three strategies,which enhance the fire safety of RPUF and maintain even improve the thermal insulation properties.This comprehensive review focuses on the up-to-date design of the reactive,additive,and coating flame retardants,and their effects on flame retardancy and thermal conductivity of RPUF.Moreover,the practical applications of the as-prepared flame-retardant RPUFs are highlighted.Finally,key challenges associated with these three kinds of flame retardants are discussed and future research opportunities are also proposed.
文摘To study the effects of different proportions of aluminum hydroxide and expandable graphite (EG) composites on flame retardation, sealing, mechanical, electrical and other properties of RTV- 1, aluminum hydroxide/expandable graphite (ATH/EG) and silicone rubber composites were prepared by the compression molding method. The experimental results show that heat resistance improves with the increase of proportion of EG. Although the resistance coefficient changes, the composite materials still keep good electrical insulating property. Moreover, oxygen index and expansion index rise first then fall. When ATH/EG is 1:1, the oxygen index reaches the highest; the mechanical property of the silicone rubber is not affected under various environments such as acid, alkali, oily, artificial sea water environments, etc.
基金The authors acknowledge financial support from the National Key Research and Development Program of China(2018YFB0703802)the National Natural Science Foundation of China(Grant Nos.51705504,21972153,and 51675512)+3 种基金the China Postdoctoral Science Foundation Funded Project(2019M653798)the Youth Innovation Promotion Association of CAS(2018454)the pre-research project in the manned space field(040101)the Gansu Province Science and Technology Plan(18ZD2WA011).
文摘A series of new halogen-free dicationic ionic liquids(ILs)with different alkyl chain lengths were prepared,and the relationship between the alkyl chain length,physicochemical and tribological properties of ILs,and their role as neat lubricant for steel–steel friction pairs,was investigated.Evaluation of stability during hydrolysis and copper strip corrosion test results show that synthetic ILs are stable and not corrosive to metal contacts,due to the halogen-free anions.The friction and wear test results indicate that ILs with long alkyl chains have excellent friction-reducing and anti-wear properties,especially at high temperatures.Based on the surface three-dimensional(3D)profiles,electrical contact resistance,scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),and the X-ray photoelectron spectrometry(XPS)analysis of the worn surfaces of steel discs,we can conclude that the efficiency of ILs is due to the formation of high quality tribofilms that consist of both tribochemical reaction and ordered absorption films.
基金This work was supported by the National Key Research and Development Program of China(No.2016YFB0401600)the National Natural Science Foundation of China(No.U1605244)China Postdoctoral Science Foundation(No.2020M681726).
文摘Poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt(4,4′-(N-(4-butylphenyl))](TFB),one of the most popular and widely used hole-transport layer(HTL)materials,has been successfully applied in high performance spin-coated quantum dots-based light-emitting diodes(QLEDs)due to its suitable energy level and high mobility.However,there are still many challenging issues in inkjet-printed QLED devices when using TFB as HTL.TFB normally suffers from the interlayer mixing and erosion,and low surface energy against the good film formation.Here,a novel environment-friendly binary solvent system was established for formulating quantum dot(QD)inks,which is based on mixing halogen-free alkane solvents of decalin and n-tridecane.The optimum volume ratio for the mixture of decalin and n-tridecane was found to be 7:3,at which a stable ink jetting flow and coffee-ring free QD films could be formed.To research the influence of substrate surface on the formation of inkjet-printed QD films,TFB was annealed at different temperatures,and the optimum annealing temperature was found to enable high quality inkjet-printed QD film.Inkjet-printed red QLED was ultimately manufactured.A maximum 18.3%of external quantum efficiency(EQE)was achieved,reaching 93%of the spin-coated QLED,which is the best reported high efficiency inkjet-printed red QLEDs to date.In addition,the inkjet-printed QLED achieved similar T75 operational lifetime(27 h)as compared to the spin-coated reference QLED(28 h)at 2,000 cd·m−2.This work demonstrated that the novel orthogonal halogen-free alkane co-solvents can improve the interfacial contact and facilitate high-performance inkjet printing QLEDs with high EQE and stability.
基金Financial support from the National Key R&D Program of China(Grant No.2022YFB4101900)National Natural Science Foundation of China(Grant Nos.22278305 and U21B2096).
文摘The atom-economical cycloaddition of CO_(2) with epoxides to synthesize cyclic carbonates is a promising route for valuable utilization of CO_(2).Halogenide such as alkali metal halides and quaternary ammonium salt have been developed as the efficient catalysts.However,the spilled halogen causes equipment corrosion and affects the product purity.To address these concerns,the halogen-free cycloaddition of CO_(2) with epoxides has always been desired.In this review,we systematically discussed the halogen-free catalysis for cycloaddition of CO_(2) with epoxides from the mechanistic insights,aiming to promote the development of efficient halogen-free catalysts.Two types of catalysts,i.e.,alternatives of halogen nucleophiles for epoxide activation,and bifunctional catalysts with Lewis acid-base sites for synergistic activation of CO_(2) and epoxides are summarized and emphasized.Specially,metal oxides as the potential halogen-free catalysts are highlighted due to their flexible acid-base sites for synergistic activation of CO_(2) and epoxides,facile preparation,and low cost.
基金supported by the National Key Research and Development Program of China(2018YFB0605801)National Natural Science Foundation of China(21871277)Chinese Academy of Sciences(QYZDYSSW-SLH013).
文摘The chemical transformation of CO2 and epoxides into cyclic carbonates has been receiving much attention and is one of the successful examples for CO2 utilization as carbon resource.Many catalysts containing halide anions have been explored and exhibit excellent catalytic activity.However,halogen salt is generally toxic and corrosive to reactors.From a green chemistry perspective,it is more attractive to develop a halogen-free catalyst with excellent performance.Herein,a review of recent research progress of halogen-free catalysts in the cycloaddition of CO2 and epoxide is presented.According to previous experimental and theoretical works,two possible strategies for achieving the halogen-free process were summarized.The relationship between catalytic activity and catalyst structure,the mechanism of CO2 activation should be both studied deeply combined with experimental results and DFT calculation,which can guide the design of new catalysts and realize halogen-free process under mild reaction conditions.
基金The work was financially supported by the Ministry of Science and Technology of China(Nos.2017YFA0206600 and 2019YFA0705900)the National Natural Science Foundation of China(Nos.21875072,U20A6002 and 51973169)+2 种基金Guangdong Innovative and Entrepreneurial Research Team Program(No.2019ZT08L075)This study also received financial support from Science and Technology Foundation of Guangdong Province(No.2021A0101180005)Special Projects in Key Areas for the University of Guangdong Province(No.2021ZDZX1009).
文摘Polymer solar cells(PSCs)consisting of a polymer donor and a small molecular acceptor is a promising photovoltaic technology,whose device performance is determined by both polymer donor and small molecular acceptor.Halogen atoms such as fluorine or chlorine atoms were usually introduced onto the polymer donors to downshift the highest occupied molecular orbital(HOMO)energy levels and improve the open-circuit voltage(VOC)of the PSCs.However,the introduction of the halogen atoms especially fluorine atoms greatly complicates the polymer synthesis.Herein,we report the use of a structural simple and easily synthesized building block,3,4-dicyanothiophene(DCT),to construct a set of halogen-free polymer donors PBCNTx(x=25,50,75)via ternary random copolymerization.The introduction of DCT units not only simplified the synthesis,but also downshifted the HOMO energy levels of the polymers and improved the V_(OC) of PSCs effectively.Encouragingly,the PBCNT75 afforded a power conversion efficiency up to 15.7%with a V_(OC) of 0.83 V,which are among the top values for halogen-free polymer donors.This work shows that the introduction of DCT units is a simple yet effective strategy to construct halogen-free and low-cost polymer donors for high-performance PSCs.
基金Thanks for financial support from the National Natural Science Foun-dation of China(No.51906252)the Natural Science Foundation of Jiangsu Province(NO.BK20190632)China Postdoctoral Science Foun-dation(2019M661980).
文摘Polystyrene(PS)is rich in plastic materials,but it produces a large amount of waste every year,causing a huge burden on the environment.Although PS plastic is the source of a common"white pollution"in daily life,it still has a high utilization value.At the same time,the flammability of PS material determines that it cannot be applicated in places where fire accidents occur frequently.As a result,its application has been greatly limited.In order to realize the efficient utilization of waste PS and broaden its scope of application,PS was modified by hyper-crosslinking in order to improve its fire-retardant performance.In this method,the PS solution with high purity was obtained by dissolving waste PS foam with 1,2-dichloroethane(DCE),and then the hyper-crosslinked polymer with high specific surface area was prepared by adding cross-linking agent formaldehyde dimethyl acetal(FDA)and a Lewis-acid catalyst ferric chloride(FeCl_(3)).Further studies showed that the effects of the amount of cross-linking agent FDA,catalyst FeCl_(3) and PS on the reaction products were different.In addition,compared the as-prepared fire-retardant materials with PS foam from the aspects of flame retardancy and thermal insulation,it can be concluded that the fire-retardant performance of the materials prepared by this method has been significantly enhanced.And it is proved that this method is feasible towards the preparation of a large number of fire-retardant composite materials by using a scale-up experiment.
基金The financial support from National Natural Science Foundation of China(21576081,21776074 and 2181101120)is greatly acknowledged.
文摘For the first time,we employed the halogen-free deep eutectic solvent(DES)into the Knoevenagel condensation between aromatic aldehydes and active methylene compounds at room temperature.The DESs[3Im:PTSA]and[4Im:PTSA]were prepared by imidazole(Im)and p-tol-uenesulfonic acid(PTSA),which were experimentally screened from a series of organic acids with imidazole.a,b-Unsaturated carbonyl compounds were obtained in good to excellent yields under solvent-free conditions with fast reaction rate.These two DESs can be reused for multiple times with no loss of catalytic activity.
文摘Bisphenol A bis(diphenyl phosphate) oligomer(BDP) is prepared successfully from the reactants consisting of phosphorus oxyehloride (POCl3), bisphenol A and phenol with a Friedel-Crafts catalyst. The resultant products were examined with thermtygravimetrie analysis (TGA) and high performance liquid chro- matography(HPLC). Thermogravimetry data shows that BDP decomposes at 375℃ when 5 % weight lost. Experiments results show that catalyst is preferably AICI3 and the amount of it is preferably 1% relative to bisphenol A by mole. POCl3/bisphenol A mole ratio is preferably about 5:1 to 6:1. Experiments unclosed that a seal apparatus is very important to the properties of product.
文摘The consumption ofthermoset resins as building polymers is approximately over one million tone word wide. The thermoset resins are proven construction materials for the technical and highly demanding applications of the transportation, electrical and building part industry. Heat stability, high thermal, low shrinkage, excellent mechanical properties are typical for their type of polymers. Above applications in addition to the mechanical properties also require good flame retardants of the materials. Undertaken activities refer to official draft, laws and legal recommendations in UE states. This paper presents positive effect of reduced flammability of thermoset resins (unsaturated polyester and epoxy resins) thanks to the use of nanocomposites containing multi-ingredient halogen-flee flame retardants which combine conventional phosphorus/nitrogen modifiers interacting with nanofillers (oMMT (organomodified montmorillonite), EG (expandable graphite), graphene, GO (graphene oxide), nSi (nanosilica)).
基金Ministry of Higher Education Malaysia for their Fundamental Research Grant Scheme (FRGS)FRGS/1/2022/TK10/UMS/02/1the International Tropical Timber Organization for the ITTO Fellowship Pro-gramme (No.070/21A)。
文摘Due to their durability,versatility,and aesthetic value,wood and wood-based composites are widely used as building materials.The fact that these materials are flammable,however,raises a major worry since they might cause fire hazards and significant loss of life and property.The article investigates the variables that affect fire performance as well as the various fire-retardant treatments and their mechanisms.The current developments and challenges in improving the fire performance of wood and wood-based composites treated with fire-retardant materials are summarized in this paper.Nanoparticles,organic chemicals,and densification are some recent developments in fire-retardant treatments that are also emphasized.Key points from the review are summarized,along with potential areas for further research and development.
基金supported by the Fundamental Research Funds for the Central Universities(2232019A3-03)the National Natural Science Foundation of China(52073053,21674019)+3 种基金Shanghai Rising-Star Program(21QA1400300)Shanghai Municipal Education Commission(17CG33)Innovation Program of Shanghai Municipal Education Commission(2021-01-07-00-03-E00108)Science and Technology Commission of Shanghai Municipality(20520741100)。
文摘The materials with thermal insulating and fre-retardant properties are highly demanded for architectures to improve the energy efficiency.The applications of conventional inorganic insulating materials such as silica aerogels are restricted by their mechanical fragility and organic insulating materials are either easily ignitable or exhibit unsatisfactory thermal insulation performance.Here,we report an organic/inorganic composite aerogel with integrated double network structure,in which silica constituent homogeneously distribute in the anisotropic polyimide nanofber aerogel matrix and strong interfacial effect is formed between two components.The integrated binary network endows the polyimide/silica composite aerogels with outstanding compressibility and flexibility even with a high inorganic content of 60%,which can withstand 500 cyclic fatigue tests at a compressive strain of 50%in the radial direction.The resulting composite aerogel exhibits a combination of outstanding insulating performance with a low thermal conductivity(21.2 mW m^(-1)K^(-1))and excellent resistance to a 1200℃flame without disintegration.The high-performance polyimide/silica aerogels can decrease the risk brought by the collapse of reinforced concrete structures in a fre,demonstrating great potential as efficient building materials.
基金Supported by the Social Public Benefit Research Special Funds of Scientific Research Institute of China (Grant No. 2005DIA2J007)the Applying Innovation Plan Funds of Ministry of Public Security of China (Grant No. 2005YYCXSCXF008)
文摘This paper investigated the fire-retardant mechanism of the nano-LDHs in the intumescent system by the temperature programmed oxidation (TPO). Researches were also conducted to explore the function of the nano-LDHs in the composite fire-retardant agents in air and nitrogen atmosphere, respectively. The results indicated that the nano-LDHs species were responsible for the catalytic oxidation of the rich-carbon compound in oxygen atmosphere. In addition, the nano-LDHs species and their calcinated products at high temperature could increase the carbonaceous residue-shield of the carbon-rich materials, improve the quality and the graphitization degree of the formed char-layer, and accelerate the intumescence and expansion of the melting carbon-rich materials to a certain degree under the oxygen-free condition, leading to the carbonization and expansion of the intumescent layer.
基金We thank Y.Huang from Tsinghua University for the help in characterizing colored CFs samplessupported by the National Natural Science Foundation of China(Grant Nos.51903008 and U1910209)+6 种基金Science and Technology Research Project of the Educational Commission of Hubei Province(D20211703)Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.2023433)Natural Science Foundation of Shanxi Province(Grant No.20210302124128)Open Foundation of State Key Laboratory of Bio-Fibers and Eco-Textiles from Qingdao University(Grant No.2020105)Hubei Key Laboratory of Digital Textile Equipment,Wuhan Textile University(Grant No.DTL 2022006)National Engineering Laboratory for Modern Silk,Soochow University(Grant No.SDGC2148)National Local Joint Laboratory for Advanced Textile Processing and Clean Production(Grant No.17).
文摘Carbon fibers(CFs)are widely used in various cutting-edge fields,such as aerospace,military,automobiles,and sports,owing to their unique combination of excellent mechanical properties,good thermal stability,and lightweight.However,their inherent super-black appearance makes it difficult to satisfy the aesthetic/fashion requirements of the colorful world,and the flammability of CFs severely limits their practical utilization in high-temperature and other extreme environments.Herein,we fabricated full-color tunable colored CFs on a large-scale via atomic layer deposition,based on the monolayer film interference strategy.CFs exhibited brilliant colors and excellent environmental durability in extreme environments,such as intense ultraviolet(UV)irradiation,accelerated laundering,friction,high-temperature,and low-temperature treatments.Colored CFs also exhibited excellent fire-retardant performance that could withstand alcohol-lamp flame burning for 60 min.Our work provides insights into an innovative material/structural design that can help achieve rapid development of the CF industry and global carbon neutrality/sustainability.
基金financial support from the National Natural Science Foundation of China (91333204, 21325419 and 51673201)the Chinese Academy of Sciences (XDB12030200, KJZD-EW-J01)+3 种基金the National Basic Research Program 973 (2014CB643501)the CAS-Croucher Funding Scheme for Joint Laboratories (CAS14601)supported by the US Office of Naval Resea (ONR) grant N00141512322supported by a Research Opportunity Initiative grant by the UNC General Administatrtion
文摘Though the power conversion efficiencies(PCEs) of organic solar cells(OSCs) have been boosted to 12%,the use of highly pollutive halogenated solvents as the processing solvent significantly hinders the mass production of OSCs. It is thus necessary to achieve high-efficiency OSCs by utilizing the halogen-free and environmentally-friendly solvents. Herein, we applied a halogen-free solvent system(oxylene/1-phenylnaphthalene, XY/PN) for fabricating fullerene-free OSCs, and a high PCE of 11.6% with a notable fill factor(FF) of 72% was achieved based on the PBDB-T:IT-M blend, which is among the top efficiencies of halogen-free solvent processed OSCs. In addition, the influence of different halogen-free solvent additives on the blend morphology and device performance metrics was studied by synchrotron-based tools and other complementary methods. Morphological results indicate the highly ordered molecular packing and highest average domain purity obtained in the blend films prepared by using XY/PN co-solvent are favorable for achieving increased FFs and thus higher PCEs in the devices.Moreover, a lower interaction parameter(χ) of the IT-M:PN pair provides a good explanation for the more favorable morphology and performance in devices with PN as the solvent additive, relative to those with diphenyl ether and Nmethylpyrrolidone. Our study demonstrates that carefully screening the non-halogenated solvent additive plays a vital role in realizing the efficient and environmentally-friendly solvent processed OSCs.