MPHPB was prepared from melamine,phenylphosphonic acid and boric acid,and its flame retardant effect in PE was investigated.Compared to the intermediate product(melamine phenyl hypophosphite(MPHP)),the residual char i...MPHPB was prepared from melamine,phenylphosphonic acid and boric acid,and its flame retardant effect in PE was investigated.Compared to the intermediate product(melamine phenyl hypophosphite(MPHP)),the residual char increased from 17.9% of MPHP to 41.2% of MPHPB at 800℃.The limiting oxygen index(LOI)of PE/20%MPHPB is 23.6%,which reaches V-0 rating.After the addition of 20%MPHPB,the total heat release(THR),peak heat release rate(pK-HRR),and average effective thermal combustion rates(av-EHC)of PE decreased.Additionally,characterizations including the pyrolysis gas chromatography-mass spectrometry(Py-GC-MS),scanning electron microscopy(SEM),raman spectroscopy test(LRS)and fourier transform infrared(FT-IR)were taken to investigate the flame retardant mechanism,and the results show that MPHPB plays roles in both gas and condensed phases.展开更多
By combining the merits of radiative cooling(RC)and evaporation cooling(EC),radiative coupled evaporative cooling(REC)has attracted considerable attention for sub-ambient cooling purposes.However,for outdoor devices,t...By combining the merits of radiative cooling(RC)and evaporation cooling(EC),radiative coupled evaporative cooling(REC)has attracted considerable attention for sub-ambient cooling purposes.However,for outdoor devices,the interior heating power would increase the working temperature and fire risk,which would suppress their above-ambient heat dissipation capabilities and passive water cycle properties.In this work,we introduced a REC design based on an all-in-one photonic hydrogel for above-ambient heat dissipation and flame retardancy.Unlike conventional design RC film for heat dissipation with limited cooling power and fire risk,REC hydrogel can greatly improve the heat dissipation performance in the daytime with a high workload,indicating a 12.0℃lower temperature than the RC film under the same conditions in the outdoor experiment.In the nighttime with a low workload,RC-assisted adsorption can improve atmospheric water harvesting to ensure EC in the daytime.In addition,our REC hydrogel significantly enhanced flame retardancy by absorbing heat without a corresponding temperature rise,thus mitigating fire risks.Thus,our design shows a promising solution for the thermal management of outdoor devices,delivering outstanding performance in both heat dissipation and flame retardancy.展开更多
Developing polymer materials combining high strength,toughness,multifunctionality,and environmental sustainability remains a major challenge.Herein,high-performance PVA-PCSx composite films were successfully fabricate...Developing polymer materials combining high strength,toughness,multifunctionality,and environmental sustainability remains a major challenge.Herein,high-performance PVA-PCSx composite films were successfully fabricated by incorporating H_(3)PO_(3)-protonated chitosan(PCS)into the PVA matrix as both a bio-based multi-hydrogen-bonding crosslinking agent and a macromolecular flame retardant.Specifically,a comprehensive investigation was conducted on the hydrogen bonding interactions,microstructure,mechanical properties,antibacterial performance,and flame retardancy of the PVA-PCSx films.Strong hydrogen bonds between PCS and PVA enabled excellent compatibility and formed a unique mechanical interlocking interface architecture.This further resulted in superior transparency and synchronous reinforcement and toughening effects in the composites films.Compared with pure PVA,the PVA-PCSx films showed a 23%-51%increase in tensile strength and an 80%-108%improvement in fracture toughness.Moreover,PVA-PCSx films exhibited superior fire safety performance,achieving an LOI value of 31.3%,attaining UL-94 V-0 rating,and reducing the heat release rate by up to 73.1%.Additionally,PVA-PCSx films demonstrated 99.99%antibacterial efficacy against both Escherichia coli and Staphylococcus aureus.Collectively,this study presents a simple yet effective strategy for fabricating high-strength,high-toughness,multifunctional composites using biopolysaccharides as additives.展开更多
In this manuscript,we conveniently prepared a series of polyester-polycarbonate copolymer(PPC-P)/polybutylene adipate terephthalate(PBAT)blends that exhibit both flame-retardant properties and toughness.Piperazine pyr...In this manuscript,we conveniently prepared a series of polyester-polycarbonate copolymer(PPC-P)/polybutylene adipate terephthalate(PBAT)blends that exhibit both flame-retardant properties and toughness.Piperazine pyrophosphate(PAPP),melamine phosphate(MPP)and ZnO were used as synergistic flame retardants for PPC-P/PBAT blends.The effects of synergistic flame retardants on thermal stability,combustion behavior and flame retardancy of PPC-P/PBAT blends were investigated.The results showed that when the ratio of PAPP/MPP/ZnO was 18.4:9.2:2.4,the LOI of PPC-P/PBAT composite was 42.8%,and UL-94 reached V-0 level.The results of cone calorimetry showed that the mass loss rate(MLR),the peak value of the biggest smoke production rate(pSPR)and total smoke production(TSP)of the material decreased,and a continuously expanded carbon layer with a compact structure was formed after combustion.The carbon layer formed after surface combustion protects the material from decomposition over a long temperature range.In terms of mechanical properties,compared with the composites with only PAPP and MPP,PAPP/MPP/ZnO composites can improve the mechanical properties.After adding 2.4 wt% ZnO,the tensile strength and impact strength of the polymer increased to 34.2 MPa and 28.5 kJ/m^(2),respectively.The results showed that the use of non-toxic,environmentally friendly,halogen-free flame retardants to enhance the flame retardant properties of biodegradable polymer composites is a promising direction in the future.展开更多
Generally,gaining fundamental insights into chain processes during the combustion of flame-retardant polymers relies on the qualitative and quantitative characterization of key chain carriers.However,polymer combustio...Generally,gaining fundamental insights into chain processes during the combustion of flame-retardant polymers relies on the qualitative and quantitative characterization of key chain carriers.However,polymer combustion processes based on conventional solid-fuel combustion strategies,due to the high coupling of pyrolysis,combustion,soot formation and oxidation,exhibit relatively high complexity and poor flame stability,and lead to a huge obstacle to the use of optical diagnostics.Herein,a spatial-confinement combustion strategy,which can produce a special staged flame with multi-jets secondary wave,is devised to provide a highly decoupled combustion environment.Glowing soot particles are therefore decoupled from main chemiluminescence region and confined to the flame tip to provide a well-controlled,opticalthin test environment for combustion diagnostic.Based on this strategy,a multi-nozzle-separation(MNS)burner is designed and fabricated,and the combustion processes associated with four model compounds,PVC,PS,PP/TBBA blends and PP/RP blends are investigated by spontaneous spectral diagnosis,and the chemiluminescence fingerprint of key diatomic/triatomic intermediates(such as OH,CH,C_(2),ClO,Br_(2),and PHO)are clearly observed.This encouraging result means that the strategy of spatial-confinement combustion we proposed shows promising prospect in many subjects associated with combustion chain regulation,such as efficient design of flame retardants.展开更多
Different reactive flame retardants have been extensively developed for vinyl ester resins(VERs),but very few of them can yield a flame-retardant resin that meets defined standards(e.g.UL-94 V-0 rating).In this work,p...Different reactive flame retardants have been extensively developed for vinyl ester resins(VERs),but very few of them can yield a flame-retardant resin that meets defined standards(e.g.UL-94 V-0 rating).In this work,phosphorous-containing 1-vinylimidazole salts(called VIDHP and VIDPP)were synthesized through the facile neutralization of the acid and 1-vinylimidazole.VIDHP and VIDPP were then applied as flame-retardant crosslinking agents of VERs,by which phosphorus-containing groups could be incorporated into the resin chain via ionic bonds.VIDHP/VER and VIDPP/VER showed a high curing activity and can be well cured in moderate temperatures.With 20 wt.%additions of VIDHP and VIDPP,VIDHP20/VER,and VIDPP20/VER presented a limiting oxygen index value of 29.7%and 28.4%,respectively,with the latter achieving a UL 94 V0 rating.In the cone calorimetric test,compared to the unmodified VERs,VIDPP20/VER exhibited large reductions in the peak heat release rate,total heat release rate,and total smoke release rate while VIDHP20/VER demonstrated comparatively inferior performance in terms of the heat release.VIDHP20/VER and VIDPP20/VER showed good thermal stability and presented a little lower glass transition temperature than the control sample.VIDPP with a low phosphorus oxidation state(+1)demonstrated high flame-retardant activities in the gaseous phase,whereas VIDHP with a high phosphorus oxidation state(+5)primarily exhibited efficacy in the condensed phase.展开更多
The microstructure design for thermal conduction pathways in polymeric electrical encapsulation materials is essential to meet the stringent requirements for efficient thermal management and thermal runaway safety in ...The microstructure design for thermal conduction pathways in polymeric electrical encapsulation materials is essential to meet the stringent requirements for efficient thermal management and thermal runaway safety in modern electronic devices.Hence,a composite with three-dimensional network(Ho/U-BNNS/WPU)is developed by simultaneously incorporating magnetically modified boron nitride nanosheets(M@BNNS)and non-magnetic organo-grafted BNNS(U-BNNS)into waterborne polyurethane(WPU)to synchronous molding under a horizontal magnetic field.The results indicate that the continuous in-plane pathways formed by M@BNNS aligned along the magnetic field direction,combined with the bridging structure established by U-BNNS,enable Ho/U-BNNS/WPU to exhibit exceptional in-plane(λ//)and through-plane thermal conductivities(λ_(⊥)).In particular,with the addition of 30 wt%M@BNNS and 5 wt%U-BNNS,theλ//andλ_(⊥)of composites reach 11.47 and 2.88 W m^(-1) K^(-1),respectively,which representing a 194.2%improvement inλ_(⊥)compared to the composites with a single orientation of M@BNNS.Meanwhile,Ho/U-BNNS/WPU exhibits distinguished thermal management capabilities as thermal interface materials for LED and chips.The composites also demonstrate excellent flame retardancy,with a peak heat release and total heat release reduced by 58.9%and 36.9%,respectively,compared to WPU.Thus,this work offers new insights into the thermally conductive structural design and efficient flame-retardant systems of polymer composites,presenting broad application potential in electronic packaging fields.展开更多
Sodium-ion batteries hold great promise as next-generation energy storage systems.However,the high instability of the electrode/electrolyte interphase during cycling has seriously hindered the development of SIBs.In p...Sodium-ion batteries hold great promise as next-generation energy storage systems.However,the high instability of the electrode/electrolyte interphase during cycling has seriously hindered the development of SIBs.In particular,an unstable cathode–electrolyte interphase(CEI)leads to successive electrolyte side reactions,transition metal leaching and rapid capacity decay,which tends to be exacerbated under high-voltage conditions.Therefore,constructing dense and stable CEIs are crucial for high-performance SIBs.This work reports localized high-concentration electrolyte by incorporating a highly oxidation-resistant sulfolane solvent with non-solvent diluent 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether,which exhibited excellent oxidative stability and was able to form thin,dense and homogeneous CEI.The excellent CEI enabled the O3-type layered oxide cathode NaNi_(1/3)Mn_(1/3)Fe_(1/3)O_(2)(NaNMF)to achieve stable cycling,with a capacity retention of 79.48%after 300 cycles at 1 C and 81.15%after 400 cycles at 2 C with a high charging voltage of 4.2 V.In addition,its nonflammable nature enhances the safety of SIBs.This work provides a viable pathway for the application of sulfolane-based electrolytes on SIBs and the design of next-generation high-voltage electrolytes.展开更多
The oxidation behavior and mechanism of Mg-Ca alloys in air and under flame exposure were studied.Results show that for the oxidation in air,the Mg-Ca-O oxide film with Ca accumulation and low Mg vapor pressure on the...The oxidation behavior and mechanism of Mg-Ca alloys in air and under flame exposure were studied.Results show that for the oxidation in air,the Mg-Ca-O oxide film with Ca accumulation and low Mg vapor pressure on the surface of Mg-Ca alloys with high Ca content shows good protective effect.However,the falling off phenomenon of the oxide film on Mg_(2)Ca results in the further oxidation.Hence,the Mg-Ca alloys with high Ca content only show good protective effect.For the oxidation in flame,the molten alloys release the Ca atoms to diffuse outward.The Mg-Ca-O oxide film with high Ca accumulation layer forms in Mg-Ca alloys with high Ca content.Despite the high Mg vapor pressure in the molten alloy,the Mg-Ca-O oxide film with high Ca accumulation layer shows excellent protective effect.展开更多
To further expand the application of Mg alloys at high temperatures,the oxidation resistance of Mg-0.3Ca and Mg-3.6Ca alloys with protective coating under flame exposure was studied.Results show that the oxidation res...To further expand the application of Mg alloys at high temperatures,the oxidation resistance of Mg-0.3Ca and Mg-3.6Ca alloys with protective coating under flame exposure was studied.Results show that the oxidation resistance of Mg-Ca alloys under flame exposure is significantly improved by the protective coating,and Mg-3.6Ca alloy shows better oxidation resistance performance.The surface temperature of Mg-Ca alloys is reduced by the coating,therefore improving the oxidation resistance under flame exposure.However,the thermal insulation effect of the coating on Mg-3.6Ca alloy is better,which can be attributed to the Ca accumulation on the surface film.In addition,the surface film with Ca accumulation layer plays a crucial role in protecting the alloy.No obvious Ca accumulation layer exists on the Mg-0.3Ca alloy surface,presenting a restricted protective effect.Nevertheless,the surface film containing Ca accumulation layer is formed on Mg-3.6 Ca alloy,which shows an excellent protective effect.展开更多
A novel eco-friendly charring agent(L-OH)was successfully synthesized by combining pentaerythritol(PER)with lignin through a simple two-step reaction.The structure of L-OH was characterized using Fourier transform inf...A novel eco-friendly charring agent(L-OH)was successfully synthesized by combining pentaerythritol(PER)with lignin through a simple two-step reaction.The structure of L-OH was characterized using Fourier transform infrared(FTIR),X-ray diffraction(XRD),scanning electron microscopy(SEM)and EDS.In addition,L-OH was introduced into polypropylene(PP)together with melamine(MEL)and ammonium polyphosphate(APP)as an intumescent flame retardant(IFRR).The flame retardancy of PP/IFRR composites were investigated using limited oxygen index(LOI),UL-94,thermogravimetric analysis(TGA)and cone calorimeter(CC)test.The experimental results indicate that the PP/IFRR composites pass the V-0 grade of the UL-94 test when the addition amount of IFRR is no less than 20%,and the LOI value of the composite reaches 32.2%at 30%IFRR addition.The peak heat release rate(PHRR)and peak smoke production rate(PSPR)of the composite decrease by 72.8%and 70.4%compared with pure PP,respectively.The flame retardancy mechanism was investigated by TGA,TG-FTIR and residual carbon analysis.These analyses indicate that L-OH can form a more continuous and dense carbon layer during the combustion process,which is the main factor contributing to the improved flame retardancy of PP.展开更多
We aimed to enhance the flame retardancy of epoxy resin(EP)by synthesizing a novel,halogen-free flame retardant through a one-pot method.The synthesis utilized 9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide(DOPO)...We aimed to enhance the flame retardancy of epoxy resin(EP)by synthesizing a novel,halogen-free flame retardant through a one-pot method.The synthesis utilized 9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide(DOPO),furfurylamine(FA),and benzene propionaldehyde(BPA)as raw materials.We conducted differential scanning calorimetry(DSC)analysis to investigate the effects of FPD on the curing process and thermal properties of EP.Our findings reveal that incorporating FPD into EP can facilitate a faster curing process and increase the carbon residue post-combustion.Specifically,the FPD/EP-7 composite demonstrates a limiting oxygen index(LOI)of 34.9%and achieves a UL-94V-0 rating with a phosphorus content of 0.91wt%.These results indicate that FPD significantly enhances the thermal stability and charring rate of EP,thereby improving its flame retardancy.Although the addition of FPD slightly reduces the mechanical properties of EP,the composite material maintains excellent performance.展开更多
The widespread presence of organophosphate flame retardants(OPFRs)in aquatic environments has raised significant concerns regarding environmental and hu-man health risks.In this study,the adsorption behavior of two re...The widespread presence of organophosphate flame retardants(OPFRs)in aquatic environments has raised significant concerns regarding environmental and hu-man health risks.In this study,the adsorption behavior of two representative aromatic OPFRs,triphenylphosphine ox-ide(TPPO)and triphenyl phosphate(TPhP),was system-atically investigated using organically modified montmoril-lonite(MMT).The effects of various environmental and operational parameters,including cationic surfactant dos-age,temperature,pH,ionic strength,and humic acid(HA)concentration,on OPFR adsorption were thoroughly examined.Results revealed that modification with hexa-decyltrimethylammonium bromide enhanced the TPPO and TPhP adsorption capacities of MMT.The adsorption pro-cess was largely independent of pH and HA concentration,and the presence of inorganic cations significantly improved the adsorption efficiency.Adsorption equilibrium was achieved within 30 min,with kinetics best described by a pseudo-second-order model.The adsorption isotherms ex-hibited a linear relationship,and the distribution coefficients for TPPO and TPhP were 0.16 and 0.51 L/g,respectively.Thermodynamic analysis indicated that the considered ad-sorption was more favorable at lower temperatures.The pri-mary adsorption mechanism was attributed to the partition-ing behavior facilitated by the organophilic nature of the modified MMT.Moreover,the adsorbent demonstrated ex-cellent regeneration performance,with its adsorption capac-ity remaining stable over five consecutive cycles.Overall,these findings show that cationic surfactant-modified MMT has a promising potential for application in wastewater treat-ment to effectively remove OPFRs from aqueous systems.展开更多
Highly flame-retardant bio-based composites were prepared in this study.Firstly,glucose-citric acid(GC)resin was synthesized through the interaction of glucose and citric acid derived from agricultural and forestry so...Highly flame-retardant bio-based composites were prepared in this study.Firstly,glucose-citric acid(GC)resin was synthesized through the interaction of glucose and citric acid derived from agricultural and forestry sources.Polyvinyl alcohol(PVA)served as a toughening agent,whereas walnut shell powder(WSP)functioned as a filler in the formulation of a thermosetting bio-based GC-PVA-WSP(GCPW)composite with GC resin.The findings demonstrated that boric acid increased the limited oxygen index(LOI)value of GCPW to 33%,while simultaneously diminishing its total smoke production(TSP)by 99.9%,and achieving a flame retardant index(FRI)of 5.04.In addition,the incorporation of WSP enhanced the compressive strength of the GCPW composite to 9.15 MPa.Concurrently,the GCPW composite demonstrates excellent hydrophobic properties,with a thermal conductivity as low as 0.086 W/m·K.展开更多
Poly(vinyl alcohol)(PVA)is a biodegradable and environmentally friendly material known for its gas barrier characteristics and solvent resistance.However,its flammability and water sensitivity limit its application in...Poly(vinyl alcohol)(PVA)is a biodegradable and environmentally friendly material known for its gas barrier characteristics and solvent resistance.However,its flammability and water sensitivity limit its application in specialized fields.In this study,phytic acid(PA)was introduced as a halogen-free flame retardant and biochar(BC)was introduced as a reinforcement to achieve both flame resistance and mechanical robustness.We thoroughly investigated the effects of BC particle sizes(100-3000 mesh)and addition amounts(0 wt%-10 wt%),as well as PA addition amounts(0 wt%-15 wt%),on the properties of PVA composite films.Notably,the PA10/1000BC5 composite containing 10 wt%PA and 5 wt%1000 mesh BC exhibited optimal properties.The limiting oxygen index increased to 39.2%,and the UL-94 test achieved a V-0 rating.Additionally,the PA10/1000BC5 composite film demonstrated significantly enhanced water resistance,with a swelling ratio reaching 800%without dissolving,unlike that of the control PVA.The water contact angle was 70°,indicating that hydrophilic properties remained essentially unaffected.Most importantly,the tensile modulus and elongation at break were 213 MPa and 281.7%,respectively,nearly double those of the PVA/PA composite film.This study presents an efficient and straightforward method for preparing PVA composite films that are flame-retardant,tough,and waterresistant,expanding their potential applications in various fields.展开更多
In recent years,polymer-based triboelectric nanogenerators(TENGs)have been increasingly applied in the field of flexible wearable electronics.However,the lack of flame retardancy of existing TENGs greatly lim-its thei...In recent years,polymer-based triboelectric nanogenerators(TENGs)have been increasingly applied in the field of flexible wearable electronics.However,the lack of flame retardancy of existing TENGs greatly lim-its their applications in extreme circumstances.Herein,an ultra-thin and highly flexible aramid nanofiber(ANF)/MXene(Ti_(3)C_(2)T_(x))/Ni nanochain composite paper was prepared through vacuum-assisted filtration and freeze-drying technology.Owing to the synergistic effect between ANF and MXene,the composite paper not only possessed excellent mechanical properties,which were able to withstand over 10,000 times its own weight,but also exhibited outstanding flame-retardant and controllable Joule heating ca-pabilities.Moreover,the mechanical energy capture characteristics of the composite paper-based TENG were evaluated,resulting in the open-circuit voltage(55.6 V),short-circuit current(0.62μA),and trans-ferred charge quantity(25μC).It also could enable self-powering as a wearable electronic device with an instantaneous power of 15.6μW at the optimal external resistance of 10 MΩ.This work is intended to set TENG as safe energy harvesting devices for reducing fire hazards,and will provide a new strategy to broaden the application ranges of TENG.展开更多
The rational utilization of nuclear energy is crucial in current global energy system.Using a flame denitrificationreactor,this study develops uranium trioxide(UO_(3)),a critical intermediate product in the nuclear fu...The rational utilization of nuclear energy is crucial in current global energy system.Using a flame denitrificationreactor,this study develops uranium trioxide(UO_(3)),a critical intermediate product in the nuclear fuel cycle,and systematically characterizes its physicochemical properties.The UO_(3) products are comprehensively examined to assess their suitability for downstream nuclear industry applications.Our results indicates that high-quality UO_(3) products can be obtained using flamedenitrificationreactor at temperatures between 440℃ and 480℃.This study reveals the considerable potential of UO_(3) production via flamedenitrification,marking a significantadvancement towards enhanced nuclear fuel cycle systems.展开更多
The construction of hierarchical thermoplastic polyurethane(TPU)composites with superior flame retardant and electromagnetic shielding capabilities hold significant practical importance.In this work,TPU composites loa...The construction of hierarchical thermoplastic polyurethane(TPU)composites with superior flame retardant and electromagnetic shielding capabilities hold significant practical importance.In this work,TPU composites loaded with a multilayer core-shell flame retardant(APP@CoAl-LDH@Si)and a modified conductive nanofiller(MWCNT-NH_(2)-PA)were firstly prepared through the melt blending method,acting as surface layer.Additionally,multilayered MXene films functionalized by bacterial cellulose(BC)and dopamine hydrochloride(DA)were fabricated via a facile and efficient vacuum filtration approach.Finally,a PBM film was utilized as an intermediate layer to construct hierarchical TPU composites.The results indicated that the introduction of 10 wt%APP@CoAl-LDH@Si hybrid,the peak heat release rate,total heat release,peak smoke production rate,and total smoke release of the TPU composites were decreased by 83.0%,61.3%,48.5%and 66.9%,respectively,compared with those of pure TPU due to the free radicals capture effect of APP,and the flame-retardant functions of LDH and silane.Moreover,the hierarchical TPU/APP@CoAl-LDH@Si/CP1-PBM exhibited excellent electromagnetic shielding performance,achieving 43.6 dB in the X-band because of multiple reflection losses,interface polarization losses,and charge carrier movement-induced thermal dissipation.Extraordinarily,the A and R coefficients were reversed in the X and K bands.This phenomenon was attributed to the different degrees of confinement of the multilayer structure to electromagnetic waves with different wavelengths.This work presents a novel model for the design and preparation of high-performance polymer composites with multiple properties and regulation mechanism.展开更多
Power cables are important pieces of equipment for energy transmission,but achieving a good balance between flame retardancy and mechanical properties of cable sheaths remains a challenge.In this work,a novel intumesc...Power cables are important pieces of equipment for energy transmission,but achieving a good balance between flame retardancy and mechanical properties of cable sheaths remains a challenge.In this work,a novel intumescent flame retardant(IFR)system containing silicone-containing macromolecular charring agent(Si-MCA)and ammonium polyphosphate(APP)was designed to synergistically improve the flame retardancy and mechanical properties of ethylene-butyl acrylate copolymer(EBA)composites.The optimal mass ratio of APP/Si-MCA was 3/1 in EBA composites(EBA/APP-Si-31),corresponding to the best flame retardancy with 31.2% of limited oxygen index(LOI),V-0 rating in UL-94 vertical burning test,and 76.4%reduction on the peak of heat release rate(PHRR)in cone calorimeter test.The enhancement mechanism was attributed to the synergistic effect of APP/Si-MCA during combustion,including the radical-trapping effect,the dilution effect of non-flammable gases,and the barrier effect of the intumescent char layer.Meanwhile,the tensile results indicated that EBA/APP-Si-31 also exhibited good mechanical properties with the addition of maleic anhydride-grafted polyethylene(PE-g-MA)as the compatibilizer.Thus,the APP/Si-MCA combination is an effective IFRs system for preparing high-performance EBA composites,and it will promote their applications as cable sheath materials.展开更多
The demand for anisotropic aerogels with excellent comprehensive properties in cutting-edge fields such as aerospace is growing.Based on the above background,a novel heterocyclic para-aramid nanofiber/reduced graphene...The demand for anisotropic aerogels with excellent comprehensive properties in cutting-edge fields such as aerospace is growing.Based on the above background,a novel heterocyclic para-aramid nanofiber/reduced graphene oxide(HPAN/rGO)composite aerogel was prepared by combining electrospinning and unidirectional freeze-drying.The anisotropic HPAN/rGO composite aerogel exhibited a honeycomb morphology in the direction perpendicular to the growth of ice crystals,and a through-well structure of directed microchannels in the direction parallel to the temperature gradient.By varying the mass ratio of HPAN/rGO,a composite aerogel with an ultra-low density of 5.34-7.81 mg·cm^(-3) and an ultra-high porosity of 98%-99%was obtained.Benefiting from the anisotropic structure,the radial and axial thermal conductivities of HPAN/rGO-3 composite aerogel were 29.37 and 44.35 mW·m^(-1)·K^(-1),respectively.A combination of software simulation and experiments was used to analyze the effect of anisotropic structures on the thermal insulation properties of aerogels.Moreover,due to the intrinsic self-extinguishing properties of heterocyclic para-aramid and the protection of the graphene carbon layer,the composite aerogel also exhibits excellent flame retardancy properties,and its total heat release rate(THR)was only 5.8 kJ·g^(-1),which is far superior to many reported aerogels.Therefore,ultralight anisotropic HPAN/rGO composite aerogels with excellent high-temperature thermal insulation and flame retardancy properties have broad application prospects in complex environments such as aerospace.展开更多
基金Funded by the Natural Science Foundation of Guangdong(Nos.2014A030313241,2014B090901068,and 2016A010103003)。
文摘MPHPB was prepared from melamine,phenylphosphonic acid and boric acid,and its flame retardant effect in PE was investigated.Compared to the intermediate product(melamine phenyl hypophosphite(MPHP)),the residual char increased from 17.9% of MPHP to 41.2% of MPHPB at 800℃.The limiting oxygen index(LOI)of PE/20%MPHPB is 23.6%,which reaches V-0 rating.After the addition of 20%MPHPB,the total heat release(THR),peak heat release rate(pK-HRR),and average effective thermal combustion rates(av-EHC)of PE decreased.Additionally,characterizations including the pyrolysis gas chromatography-mass spectrometry(Py-GC-MS),scanning electron microscopy(SEM),raman spectroscopy test(LRS)and fourier transform infrared(FT-IR)were taken to investigate the flame retardant mechanism,and the results show that MPHPB plays roles in both gas and condensed phases.
基金financially supported by the Science and Technology Innovation Program of Hunan Province(2024RC3003)the Central South University Innovation-Driven Research Programme(2023CXQD012)the Initiative for Sustainable Energy for its financial support。
文摘By combining the merits of radiative cooling(RC)and evaporation cooling(EC),radiative coupled evaporative cooling(REC)has attracted considerable attention for sub-ambient cooling purposes.However,for outdoor devices,the interior heating power would increase the working temperature and fire risk,which would suppress their above-ambient heat dissipation capabilities and passive water cycle properties.In this work,we introduced a REC design based on an all-in-one photonic hydrogel for above-ambient heat dissipation and flame retardancy.Unlike conventional design RC film for heat dissipation with limited cooling power and fire risk,REC hydrogel can greatly improve the heat dissipation performance in the daytime with a high workload,indicating a 12.0℃lower temperature than the RC film under the same conditions in the outdoor experiment.In the nighttime with a low workload,RC-assisted adsorption can improve atmospheric water harvesting to ensure EC in the daytime.In addition,our REC hydrogel significantly enhanced flame retardancy by absorbing heat without a corresponding temperature rise,thus mitigating fire risks.Thus,our design shows a promising solution for the thermal management of outdoor devices,delivering outstanding performance in both heat dissipation and flame retardancy.
基金financially supported by the National Natural Science Foundation of China(Nos.51991351,52173100)the Taishan Scholars Program(No.tsqn202312176)the Youth Innovation Team Project of Shandong Province(No.2022KJ304)。
文摘Developing polymer materials combining high strength,toughness,multifunctionality,and environmental sustainability remains a major challenge.Herein,high-performance PVA-PCSx composite films were successfully fabricated by incorporating H_(3)PO_(3)-protonated chitosan(PCS)into the PVA matrix as both a bio-based multi-hydrogen-bonding crosslinking agent and a macromolecular flame retardant.Specifically,a comprehensive investigation was conducted on the hydrogen bonding interactions,microstructure,mechanical properties,antibacterial performance,and flame retardancy of the PVA-PCSx films.Strong hydrogen bonds between PCS and PVA enabled excellent compatibility and formed a unique mechanical interlocking interface architecture.This further resulted in superior transparency and synchronous reinforcement and toughening effects in the composites films.Compared with pure PVA,the PVA-PCSx films showed a 23%-51%increase in tensile strength and an 80%-108%improvement in fracture toughness.Moreover,PVA-PCSx films exhibited superior fire safety performance,achieving an LOI value of 31.3%,attaining UL-94 V-0 rating,and reducing the heat release rate by up to 73.1%.Additionally,PVA-PCSx films demonstrated 99.99%antibacterial efficacy against both Escherichia coli and Staphylococcus aureus.Collectively,this study presents a simple yet effective strategy for fabricating high-strength,high-toughness,multifunctional composites using biopolysaccharides as additives.
基金Financial support from National Natural Science Foundation of China(Grant No.22075298)National Key R&D Program of China(2022YFD2301204)is gratefully acknowledged.
文摘In this manuscript,we conveniently prepared a series of polyester-polycarbonate copolymer(PPC-P)/polybutylene adipate terephthalate(PBAT)blends that exhibit both flame-retardant properties and toughness.Piperazine pyrophosphate(PAPP),melamine phosphate(MPP)and ZnO were used as synergistic flame retardants for PPC-P/PBAT blends.The effects of synergistic flame retardants on thermal stability,combustion behavior and flame retardancy of PPC-P/PBAT blends were investigated.The results showed that when the ratio of PAPP/MPP/ZnO was 18.4:9.2:2.4,the LOI of PPC-P/PBAT composite was 42.8%,and UL-94 reached V-0 level.The results of cone calorimetry showed that the mass loss rate(MLR),the peak value of the biggest smoke production rate(pSPR)and total smoke production(TSP)of the material decreased,and a continuously expanded carbon layer with a compact structure was formed after combustion.The carbon layer formed after surface combustion protects the material from decomposition over a long temperature range.In terms of mechanical properties,compared with the composites with only PAPP and MPP,PAPP/MPP/ZnO composites can improve the mechanical properties.After adding 2.4 wt% ZnO,the tensile strength and impact strength of the polymer increased to 34.2 MPa and 28.5 kJ/m^(2),respectively.The results showed that the use of non-toxic,environmentally friendly,halogen-free flame retardants to enhance the flame retardant properties of biodegradable polymer composites is a promising direction in the future.
基金supported by the National Natural Science Foundation of China(No.51827803)the Fundamental Research Funds for the Central Universities,111 Center(No.B20001)Institutional Research Fund from Sichuan University(No.2021SCUNL201).
文摘Generally,gaining fundamental insights into chain processes during the combustion of flame-retardant polymers relies on the qualitative and quantitative characterization of key chain carriers.However,polymer combustion processes based on conventional solid-fuel combustion strategies,due to the high coupling of pyrolysis,combustion,soot formation and oxidation,exhibit relatively high complexity and poor flame stability,and lead to a huge obstacle to the use of optical diagnostics.Herein,a spatial-confinement combustion strategy,which can produce a special staged flame with multi-jets secondary wave,is devised to provide a highly decoupled combustion environment.Glowing soot particles are therefore decoupled from main chemiluminescence region and confined to the flame tip to provide a well-controlled,opticalthin test environment for combustion diagnostic.Based on this strategy,a multi-nozzle-separation(MNS)burner is designed and fabricated,and the combustion processes associated with four model compounds,PVC,PS,PP/TBBA blends and PP/RP blends are investigated by spontaneous spectral diagnosis,and the chemiluminescence fingerprint of key diatomic/triatomic intermediates(such as OH,CH,C_(2),ClO,Br_(2),and PHO)are clearly observed.This encouraging result means that the strategy of spatial-confinement combustion we proposed shows promising prospect in many subjects associated with combustion chain regulation,such as efficient design of flame retardants.
基金supported by the National Natural Science Foundation of China(Grant Nos.51991351 and51903132)the Young Elite Scientist Sponsorship Program by CAST(No.2022QNRC001).
文摘Different reactive flame retardants have been extensively developed for vinyl ester resins(VERs),but very few of them can yield a flame-retardant resin that meets defined standards(e.g.UL-94 V-0 rating).In this work,phosphorous-containing 1-vinylimidazole salts(called VIDHP and VIDPP)were synthesized through the facile neutralization of the acid and 1-vinylimidazole.VIDHP and VIDPP were then applied as flame-retardant crosslinking agents of VERs,by which phosphorus-containing groups could be incorporated into the resin chain via ionic bonds.VIDHP/VER and VIDPP/VER showed a high curing activity and can be well cured in moderate temperatures.With 20 wt.%additions of VIDHP and VIDPP,VIDHP20/VER,and VIDPP20/VER presented a limiting oxygen index value of 29.7%and 28.4%,respectively,with the latter achieving a UL 94 V0 rating.In the cone calorimetric test,compared to the unmodified VERs,VIDPP20/VER exhibited large reductions in the peak heat release rate,total heat release rate,and total smoke release rate while VIDHP20/VER demonstrated comparatively inferior performance in terms of the heat release.VIDHP20/VER and VIDPP20/VER showed good thermal stability and presented a little lower glass transition temperature than the control sample.VIDPP with a low phosphorus oxidation state(+1)demonstrated high flame-retardant activities in the gaseous phase,whereas VIDHP with a high phosphorus oxidation state(+5)primarily exhibited efficacy in the condensed phase.
基金support from the National Natural Science Foundation of China(22268025,52473083,and 22475176)Key Research and Development Program of Yunnan Province(202403AP140036)+2 种基金Natural Science Basic Research Program of Shaanxi(2024JC-TBZC-04)Applied Basic Research Program of Yunnan Province(202201AT070115 and 202201BE070001-031)supported by the Innovation Capability Support Program of Shaanxi(2024RS-CXTD-57).
文摘The microstructure design for thermal conduction pathways in polymeric electrical encapsulation materials is essential to meet the stringent requirements for efficient thermal management and thermal runaway safety in modern electronic devices.Hence,a composite with three-dimensional network(Ho/U-BNNS/WPU)is developed by simultaneously incorporating magnetically modified boron nitride nanosheets(M@BNNS)and non-magnetic organo-grafted BNNS(U-BNNS)into waterborne polyurethane(WPU)to synchronous molding under a horizontal magnetic field.The results indicate that the continuous in-plane pathways formed by M@BNNS aligned along the magnetic field direction,combined with the bridging structure established by U-BNNS,enable Ho/U-BNNS/WPU to exhibit exceptional in-plane(λ//)and through-plane thermal conductivities(λ_(⊥)).In particular,with the addition of 30 wt%M@BNNS and 5 wt%U-BNNS,theλ//andλ_(⊥)of composites reach 11.47 and 2.88 W m^(-1) K^(-1),respectively,which representing a 194.2%improvement inλ_(⊥)compared to the composites with a single orientation of M@BNNS.Meanwhile,Ho/U-BNNS/WPU exhibits distinguished thermal management capabilities as thermal interface materials for LED and chips.The composites also demonstrate excellent flame retardancy,with a peak heat release and total heat release reduced by 58.9%and 36.9%,respectively,compared to WPU.Thus,this work offers new insights into the thermally conductive structural design and efficient flame-retardant systems of polymer composites,presenting broad application potential in electronic packaging fields.
基金financial support by National Natural Science Foundation(NNSF)of China(Nos.52202269,52002248,U23B2069,22309162)Shenzhen Science and Technology program(No.20220810155330003)+1 种基金Shenzhen Basic Research Project(No.JCYJ20190808163005631)Xiangjiang Lab(22XJ01007).
文摘Sodium-ion batteries hold great promise as next-generation energy storage systems.However,the high instability of the electrode/electrolyte interphase during cycling has seriously hindered the development of SIBs.In particular,an unstable cathode–electrolyte interphase(CEI)leads to successive electrolyte side reactions,transition metal leaching and rapid capacity decay,which tends to be exacerbated under high-voltage conditions.Therefore,constructing dense and stable CEIs are crucial for high-performance SIBs.This work reports localized high-concentration electrolyte by incorporating a highly oxidation-resistant sulfolane solvent with non-solvent diluent 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether,which exhibited excellent oxidative stability and was able to form thin,dense and homogeneous CEI.The excellent CEI enabled the O3-type layered oxide cathode NaNi_(1/3)Mn_(1/3)Fe_(1/3)O_(2)(NaNMF)to achieve stable cycling,with a capacity retention of 79.48%after 300 cycles at 1 C and 81.15%after 400 cycles at 2 C with a high charging voltage of 4.2 V.In addition,its nonflammable nature enhances the safety of SIBs.This work provides a viable pathway for the application of sulfolane-based electrolytes on SIBs and the design of next-generation high-voltage electrolytes.
基金National Natural Science Foundation of China(52405425)Project of Natural Science Research in Higher Education Institutions in Jiangsu Province(23KJB430039)+1 种基金Major Natural Science Research Project of Higher Education Institutions in Jiangsu Province(21KJA460007)333 High Level Talent Training Project in Jiangsu Province(2022-3-12-182)。
文摘The oxidation behavior and mechanism of Mg-Ca alloys in air and under flame exposure were studied.Results show that for the oxidation in air,the Mg-Ca-O oxide film with Ca accumulation and low Mg vapor pressure on the surface of Mg-Ca alloys with high Ca content shows good protective effect.However,the falling off phenomenon of the oxide film on Mg_(2)Ca results in the further oxidation.Hence,the Mg-Ca alloys with high Ca content only show good protective effect.For the oxidation in flame,the molten alloys release the Ca atoms to diffuse outward.The Mg-Ca-O oxide film with high Ca accumulation layer forms in Mg-Ca alloys with high Ca content.Despite the high Mg vapor pressure in the molten alloy,the Mg-Ca-O oxide film with high Ca accumulation layer shows excellent protective effect.
基金General Project of Natural Science Research in Higher Education Institutions in Jiangsu Province(23KJB430039)Major Natural Science Research Project of Higher Education Institutions in Jiangsu Province(21KJA460007)National Natural Science Foundation of China(51905462)。
文摘To further expand the application of Mg alloys at high temperatures,the oxidation resistance of Mg-0.3Ca and Mg-3.6Ca alloys with protective coating under flame exposure was studied.Results show that the oxidation resistance of Mg-Ca alloys under flame exposure is significantly improved by the protective coating,and Mg-3.6Ca alloy shows better oxidation resistance performance.The surface temperature of Mg-Ca alloys is reduced by the coating,therefore improving the oxidation resistance under flame exposure.However,the thermal insulation effect of the coating on Mg-3.6Ca alloy is better,which can be attributed to the Ca accumulation on the surface film.In addition,the surface film with Ca accumulation layer plays a crucial role in protecting the alloy.No obvious Ca accumulation layer exists on the Mg-0.3Ca alloy surface,presenting a restricted protective effect.Nevertheless,the surface film containing Ca accumulation layer is formed on Mg-3.6 Ca alloy,which shows an excellent protective effect.
基金the equipment support of Sharing Platform of Scientific Equipments,Ministry of Education's Research Center for Comprehensive Utilization and Clean Process Engineering of Phosphrous Resources,Sichuan University。
文摘A novel eco-friendly charring agent(L-OH)was successfully synthesized by combining pentaerythritol(PER)with lignin through a simple two-step reaction.The structure of L-OH was characterized using Fourier transform infrared(FTIR),X-ray diffraction(XRD),scanning electron microscopy(SEM)and EDS.In addition,L-OH was introduced into polypropylene(PP)together with melamine(MEL)and ammonium polyphosphate(APP)as an intumescent flame retardant(IFRR).The flame retardancy of PP/IFRR composites were investigated using limited oxygen index(LOI),UL-94,thermogravimetric analysis(TGA)and cone calorimeter(CC)test.The experimental results indicate that the PP/IFRR composites pass the V-0 grade of the UL-94 test when the addition amount of IFRR is no less than 20%,and the LOI value of the composite reaches 32.2%at 30%IFRR addition.The peak heat release rate(PHRR)and peak smoke production rate(PSPR)of the composite decrease by 72.8%and 70.4%compared with pure PP,respectively.The flame retardancy mechanism was investigated by TGA,TG-FTIR and residual carbon analysis.These analyses indicate that L-OH can form a more continuous and dense carbon layer during the combustion process,which is the main factor contributing to the improved flame retardancy of PP.
基金Funded by the Fundamental Research Funds for the Central Universities(WUT:2023III012JL)。
文摘We aimed to enhance the flame retardancy of epoxy resin(EP)by synthesizing a novel,halogen-free flame retardant through a one-pot method.The synthesis utilized 9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide(DOPO),furfurylamine(FA),and benzene propionaldehyde(BPA)as raw materials.We conducted differential scanning calorimetry(DSC)analysis to investigate the effects of FPD on the curing process and thermal properties of EP.Our findings reveal that incorporating FPD into EP can facilitate a faster curing process and increase the carbon residue post-combustion.Specifically,the FPD/EP-7 composite demonstrates a limiting oxygen index(LOI)of 34.9%and achieves a UL-94V-0 rating with a phosphorus content of 0.91wt%.These results indicate that FPD significantly enhances the thermal stability and charring rate of EP,thereby improving its flame retardancy.Although the addition of FPD slightly reduces the mechanical properties of EP,the composite material maintains excellent performance.
基金The National Natural Science Foundation of China (No. 42377020)the Innovation Project of Nanjing Water Group Co.,Ltd.(No. YF2025-009)。
文摘The widespread presence of organophosphate flame retardants(OPFRs)in aquatic environments has raised significant concerns regarding environmental and hu-man health risks.In this study,the adsorption behavior of two representative aromatic OPFRs,triphenylphosphine ox-ide(TPPO)and triphenyl phosphate(TPhP),was system-atically investigated using organically modified montmoril-lonite(MMT).The effects of various environmental and operational parameters,including cationic surfactant dos-age,temperature,pH,ionic strength,and humic acid(HA)concentration,on OPFR adsorption were thoroughly examined.Results revealed that modification with hexa-decyltrimethylammonium bromide enhanced the TPPO and TPhP adsorption capacities of MMT.The adsorption pro-cess was largely independent of pH and HA concentration,and the presence of inorganic cations significantly improved the adsorption efficiency.Adsorption equilibrium was achieved within 30 min,with kinetics best described by a pseudo-second-order model.The adsorption isotherms ex-hibited a linear relationship,and the distribution coefficients for TPPO and TPhP were 0.16 and 0.51 L/g,respectively.Thermodynamic analysis indicated that the considered ad-sorption was more favorable at lower temperatures.The pri-mary adsorption mechanism was attributed to the partition-ing behavior facilitated by the organophilic nature of the modified MMT.Moreover,the adsorbent demonstrated ex-cellent regeneration performance,with its adsorption capac-ity remaining stable over five consecutive cycles.Overall,these findings show that cationic surfactant-modified MMT has a promising potential for application in wastewater treat-ment to effectively remove OPFRs from aqueous systems.
基金supported by the Natural Science Foundation of China(32460363)Yunnan Province Agricultural Joint Key Foundation(No.202401BD070001-029)+3 种基金Yunnan Agricultural Joint General Foundation(202101BD070001-105)the Yunnan Provincial Youth Top Talent Project(Grant No.YNWR-QNBJ-2020-166)the Foreign ExpertWorkstation(202305AF150006)the 111 Project(D21027).
文摘Highly flame-retardant bio-based composites were prepared in this study.Firstly,glucose-citric acid(GC)resin was synthesized through the interaction of glucose and citric acid derived from agricultural and forestry sources.Polyvinyl alcohol(PVA)served as a toughening agent,whereas walnut shell powder(WSP)functioned as a filler in the formulation of a thermosetting bio-based GC-PVA-WSP(GCPW)composite with GC resin.The findings demonstrated that boric acid increased the limited oxygen index(LOI)value of GCPW to 33%,while simultaneously diminishing its total smoke production(TSP)by 99.9%,and achieving a flame retardant index(FRI)of 5.04.In addition,the incorporation of WSP enhanced the compressive strength of the GCPW composite to 9.15 MPa.Concurrently,the GCPW composite demonstrates excellent hydrophobic properties,with a thermal conductivity as low as 0.086 W/m·K.
基金supported by the Zhejiang Provincial"Vanguard"and"Leading Goose"R&D Program(No.2025C02203)the Zhejiang Provincial Natural Science Foundation of China(No.LTGS24C130001)the Fund for Key Scientific Research in the Public Interest of Ningbo(No.2024S009)。
文摘Poly(vinyl alcohol)(PVA)is a biodegradable and environmentally friendly material known for its gas barrier characteristics and solvent resistance.However,its flammability and water sensitivity limit its application in specialized fields.In this study,phytic acid(PA)was introduced as a halogen-free flame retardant and biochar(BC)was introduced as a reinforcement to achieve both flame resistance and mechanical robustness.We thoroughly investigated the effects of BC particle sizes(100-3000 mesh)and addition amounts(0 wt%-10 wt%),as well as PA addition amounts(0 wt%-15 wt%),on the properties of PVA composite films.Notably,the PA10/1000BC5 composite containing 10 wt%PA and 5 wt%1000 mesh BC exhibited optimal properties.The limiting oxygen index increased to 39.2%,and the UL-94 test achieved a V-0 rating.Additionally,the PA10/1000BC5 composite film demonstrated significantly enhanced water resistance,with a swelling ratio reaching 800%without dissolving,unlike that of the control PVA.The water contact angle was 70°,indicating that hydrophilic properties remained essentially unaffected.Most importantly,the tensile modulus and elongation at break were 213 MPa and 281.7%,respectively,nearly double those of the PVA/PA composite film.This study presents an efficient and straightforward method for preparing PVA composite films that are flame-retardant,tough,and waterresistant,expanding their potential applications in various fields.
基金financially supported by the Zhejiang Provin-cial Natural Science Foundation of China(No.LQ22E030016)the National Natural Science Foundation of China(Nos.52275137,51705467),the China Postdoctoral Science Foundation(No.2022M722831)+2 种基金the Postdoctoral Research Selected Funding Project of Zhejiang Province(No.ZJ2022063)the Self-Topic Fund of Zhe-jiang Normal University(No.2020ZS04)the National Key Re-search and Development Program of China(No.2018YFE0199100).
文摘In recent years,polymer-based triboelectric nanogenerators(TENGs)have been increasingly applied in the field of flexible wearable electronics.However,the lack of flame retardancy of existing TENGs greatly lim-its their applications in extreme circumstances.Herein,an ultra-thin and highly flexible aramid nanofiber(ANF)/MXene(Ti_(3)C_(2)T_(x))/Ni nanochain composite paper was prepared through vacuum-assisted filtration and freeze-drying technology.Owing to the synergistic effect between ANF and MXene,the composite paper not only possessed excellent mechanical properties,which were able to withstand over 10,000 times its own weight,but also exhibited outstanding flame-retardant and controllable Joule heating ca-pabilities.Moreover,the mechanical energy capture characteristics of the composite paper-based TENG were evaluated,resulting in the open-circuit voltage(55.6 V),short-circuit current(0.62μA),and trans-ferred charge quantity(25μC).It also could enable self-powering as a wearable electronic device with an instantaneous power of 15.6μW at the optimal external resistance of 10 MΩ.This work is intended to set TENG as safe energy harvesting devices for reducing fire hazards,and will provide a new strategy to broaden the application ranges of TENG.
基金Xing Yuan Program of China National Nuclear Corporation(CNPE-8208)National Natural Science Foundation of China(22478056)for the financialsupport.
文摘The rational utilization of nuclear energy is crucial in current global energy system.Using a flame denitrificationreactor,this study develops uranium trioxide(UO_(3)),a critical intermediate product in the nuclear fuel cycle,and systematically characterizes its physicochemical properties.The UO_(3) products are comprehensively examined to assess their suitability for downstream nuclear industry applications.Our results indicates that high-quality UO_(3) products can be obtained using flamedenitrificationreactor at temperatures between 440℃ and 480℃.This study reveals the considerable potential of UO_(3) production via flamedenitrification,marking a significantadvancement towards enhanced nuclear fuel cycle systems.
基金financially supported by the National Natural Science Foundation of China(No.52173070)the Key research and development projects of Baoying County(No.BY202205).
文摘The construction of hierarchical thermoplastic polyurethane(TPU)composites with superior flame retardant and electromagnetic shielding capabilities hold significant practical importance.In this work,TPU composites loaded with a multilayer core-shell flame retardant(APP@CoAl-LDH@Si)and a modified conductive nanofiller(MWCNT-NH_(2)-PA)were firstly prepared through the melt blending method,acting as surface layer.Additionally,multilayered MXene films functionalized by bacterial cellulose(BC)and dopamine hydrochloride(DA)were fabricated via a facile and efficient vacuum filtration approach.Finally,a PBM film was utilized as an intermediate layer to construct hierarchical TPU composites.The results indicated that the introduction of 10 wt%APP@CoAl-LDH@Si hybrid,the peak heat release rate,total heat release,peak smoke production rate,and total smoke release of the TPU composites were decreased by 83.0%,61.3%,48.5%and 66.9%,respectively,compared with those of pure TPU due to the free radicals capture effect of APP,and the flame-retardant functions of LDH and silane.Moreover,the hierarchical TPU/APP@CoAl-LDH@Si/CP1-PBM exhibited excellent electromagnetic shielding performance,achieving 43.6 dB in the X-band because of multiple reflection losses,interface polarization losses,and charge carrier movement-induced thermal dissipation.Extraordinarily,the A and R coefficients were reversed in the X and K bands.This phenomenon was attributed to the different degrees of confinement of the multilayer structure to electromagnetic waves with different wavelengths.This work presents a novel model for the design and preparation of high-performance polymer composites with multiple properties and regulation mechanism.
基金supported by the National Natural Science Foundation of China(52473059)Taishan Scholar Constructive Engineering Foundation of Shandong Province(tsqn202103079)Key Research and Development Plan of Shandong Province(2024TSGC0264).
文摘Power cables are important pieces of equipment for energy transmission,but achieving a good balance between flame retardancy and mechanical properties of cable sheaths remains a challenge.In this work,a novel intumescent flame retardant(IFR)system containing silicone-containing macromolecular charring agent(Si-MCA)and ammonium polyphosphate(APP)was designed to synergistically improve the flame retardancy and mechanical properties of ethylene-butyl acrylate copolymer(EBA)composites.The optimal mass ratio of APP/Si-MCA was 3/1 in EBA composites(EBA/APP-Si-31),corresponding to the best flame retardancy with 31.2% of limited oxygen index(LOI),V-0 rating in UL-94 vertical burning test,and 76.4%reduction on the peak of heat release rate(PHRR)in cone calorimeter test.The enhancement mechanism was attributed to the synergistic effect of APP/Si-MCA during combustion,including the radical-trapping effect,the dilution effect of non-flammable gases,and the barrier effect of the intumescent char layer.Meanwhile,the tensile results indicated that EBA/APP-Si-31 also exhibited good mechanical properties with the addition of maleic anhydride-grafted polyethylene(PE-g-MA)as the compatibilizer.Thus,the APP/Si-MCA combination is an effective IFRs system for preparing high-performance EBA composites,and it will promote their applications as cable sheath materials.
基金supported by the National Key R&D Program of China(No.2021YFB3700103).
文摘The demand for anisotropic aerogels with excellent comprehensive properties in cutting-edge fields such as aerospace is growing.Based on the above background,a novel heterocyclic para-aramid nanofiber/reduced graphene oxide(HPAN/rGO)composite aerogel was prepared by combining electrospinning and unidirectional freeze-drying.The anisotropic HPAN/rGO composite aerogel exhibited a honeycomb morphology in the direction perpendicular to the growth of ice crystals,and a through-well structure of directed microchannels in the direction parallel to the temperature gradient.By varying the mass ratio of HPAN/rGO,a composite aerogel with an ultra-low density of 5.34-7.81 mg·cm^(-3) and an ultra-high porosity of 98%-99%was obtained.Benefiting from the anisotropic structure,the radial and axial thermal conductivities of HPAN/rGO-3 composite aerogel were 29.37 and 44.35 mW·m^(-1)·K^(-1),respectively.A combination of software simulation and experiments was used to analyze the effect of anisotropic structures on the thermal insulation properties of aerogels.Moreover,due to the intrinsic self-extinguishing properties of heterocyclic para-aramid and the protection of the graphene carbon layer,the composite aerogel also exhibits excellent flame retardancy properties,and its total heat release rate(THR)was only 5.8 kJ·g^(-1),which is far superior to many reported aerogels.Therefore,ultralight anisotropic HPAN/rGO composite aerogels with excellent high-temperature thermal insulation and flame retardancy properties have broad application prospects in complex environments such as aerospace.
