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
Energy density and safety are two crucial parameters when evaluating lithium-metal batteries(LMBs).Herein,we present an ultralight polymer-based current collector,incorporating flame-retardant materials,designed speci...Energy density and safety are two crucial parameters when evaluating lithium-metal batteries(LMBs).Herein,we present an ultralight polymer-based current collector,incorporating flame-retardant materials,designed specifically for thin lithium-metal anodes.Compared to the traditional copper current collector(8.96 mg cm^(-2),10μm thick),the polymer-based current collector(12μm thick)has a significantly lower areal density of 1.41 mg cm^(-2),i.e.,only one-sixth of the copper collector,thus enabling substantially higher energy densities.Accordingly,when employed in Li||NMC_(622)full-cells,the polymer-based current collector enables a specific energy of 449 Wh kg^(-1),representing a notable improvement of about14.5%compared to cells employing a classic copper current collector.The inclusion of Al(OH)_(3) as a flame retardant into the current collector suppresses flammability and,thereby,significantly improves the safety of the resulting LMBs.展开更多
A new principle for producing fire-resistant polymer materials with increased deformation properties using a flame retardant not as a heterogeneous additive,but as a thermoplastic flame retardant in a hybrid polymer m...A new principle for producing fire-resistant polymer materials with increased deformation properties using a flame retardant not as a heterogeneous additive,but as a thermoplastic flame retardant in a hybrid polymer mixture with a polyhydrocarbon is considered.Hybrid polymer blends of low-molecular ammonium polyphosphate(APP)with an ethylene-vinyl acetate copolymer(EVA)with an APP content of 80 wt%with enhanced deformation properties were obtained by extrusion mixing at various temperatures in the range from 200°C to 250°C.A chemical scheme for the transformations of the components during the formation of the composite is proposed.X-ray diffraction analysis showed the formation of new crystalline structures of APP.The phase structure of the systems corresponding to the model of a dispersed-filled composite in which EVA plays the role of a matrix,determining the deformation of the mixture,and the filler is ammonium polyphosphate,was studied by scanning electron microscopy(SEM).The method of FTIR microscopy showed chemical interactions between EVA and APP with the formation of amide groups.The conditions for obtaining compositions characterized by heat resistance of 210°C,oxygen index of 55 and ultimate elongation at drawing of 213%were established.展开更多
Bio-based 2,5-furandicarboxylic acid polyesters offer significant promise for reducing energy and environmental crises.However,their intrinsic flammability remains a critical limitation,and conventional flame-retardan...Bio-based 2,5-furandicarboxylic acid polyesters offer significant promise for reducing energy and environmental crises.However,their intrinsic flammability remains a critical limitation,and conventional flame-retardant strategies often compromise their mechanical properties,hindering their practical applications.Herein,a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO)-based comonomer(DDP)was used to synthesize flame-retardant poly(ethylene furandicarboxylate-co-phosphaphenanthrene)(PEFDn).The covalent integration of DDP confers intrinsic flame retardancy,avoiding the plasticization and migration issues associated with additive-type systems.Upon thermal decomposition,the DOPO-derived moieties release phosphoric acid and radical scavengers,promoting char formation and suppressing flame propagation.Furthermore,density functional theory(DFT)calculations combined with non-covalent interaction(NCI)analysis revealed that DOPO dimer molecules adopt a stable parallel-displaced π-π stacking configu ration,potentially facilitating microphase separation and enhancing the energy dissipation capability.PEFD_(10)achieves a UL-94 V-0 rating while simultaneously increasing impact toughness from 1.5 kJ/m^(2) to 14.7 kJ/m^(2).Im portantly,PEFDn maintained acceptable oxygen-barrier properties.PEFD10 also exhibited high transparency and UV-shielding performance.The combination of intrinsic flame safety,im pact-toughness resistance,UV shielding,and an oxygen barrier ensures reliable protection of electrical components and long-term operational stability.The integration of multiple critical properties within a single bio-based material represents a novel approach fo r enabling sustainable polymer solutions for high-pe rformance electrical applications.展开更多
Although poly(urethane-urea)elastomers(PUEs)possess excellent mechanical properties and durability,their inherent flammability and inability to self-repair after damage significantly limits their applications in high-...Although poly(urethane-urea)elastomers(PUEs)possess excellent mechanical properties and durability,their inherent flammability and inability to self-repair after damage significantly limits their applications in high-end fields.To address this challenge,this study employs a supramolecular chemistry approach by simultaneously incorporating multiple hydrogen bonds as dynamic cross-linking points and a phosphorus-nitrogen synergistic flame-retardant structure into the poly(urethane-urea)network.The multiple hydrogen bonds endow the material with efficient intrinsic self-healing capability,while the phosphorus-nitrogen flame retardant ensures outstanding thermal stability and flame resistance,leading to the successful synthesis of a high-performance multifunctional poly(urethane-urea)elastomer.Experimental results demonstrated that when the content of the flame retardant diethyl(2-((2-aminoethyl)amino)ethyl)phosphoramidate(DEPTA)was 10 wt%,the resulting PUE/10%DEPTA achieved a V-0 rating in the vertical burning test,with a limiting oxygen index(LOI)of 30%.Concurrently,the elastomer maintained good toughness,exhibiting a tensile strength of 27.3 MPa,an elongation at break of 601%,and a self-healing efficiency of up to 94.46%.This breakthrough shows significant promise for advanced engineering applications that demand fire safety,structural durability,and extended service life through self-repair.展开更多
Polyurea(PUA)is widely valued in protective coatings and structural reinforcement because of its impressive mechanical strength and resistance to corrosion.Its high flammability,together with the poor dispersion that ...Polyurea(PUA)is widely valued in protective coatings and structural reinforcement because of its impressive mechanical strength and resistance to corrosion.Its high flammability,together with the poor dispersion that often comes with simply blending in flame retardants,continues to limit its use in demanding environments.To overcome these issues,this study introduces a different approach.We grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO)onto the surface of a metal-organic framework(MOF)and then partially amino-functionalized the DOPO layer,ultimately creating an amino-modified DOPO-MOF hybrid.The introduced amino groups can directly react with the isocyanate(-NCO)groups in the PUA matrix,allowing the flame-retardant component to be integrated via reactive integration rather than physical blending.This approach helps avoid the interfacial defects and the mechanical weakening typically observed in conventional blending.With 5 wt% ZIF-67@DOPO-NH2 added to the PUA system,the composite successfully reached a UL-94 V-0 classification and showed a notable increase in limiting oxygen index(LOI),from19.2% to 23.8%.The peak heat release rate and total heat release dropped by 36.3% and 38.7%,respectively.Meanwhile,the tensile strength decreased from 25.74 to 22.52 MPa,while the elongation at break remained above 300%,indicating that the material maintained excellent toughness.展开更多
Gel-based room-temperature phosphorescence(RTP)materials have garnered significant attention due to their promising applications in flexible electronics and photonics.However,the inherent swollen state and porous arch...Gel-based room-temperature phosphorescence(RTP)materials have garnered significant attention due to their promising applications in flexible electronics and photonics.However,the inherent swollen state and porous architecture of such gels often promote intense molecular motion and facilitate oxygen diffusion,which can severely quench phosphorescence under ambient conditions.In this work,we report a versatile strategy for constructing high-performance organic RTP materials by leveraging organic aerogels,which exhibit superior luminescent,mechanical,and thermal properties.Owing to their structural advantages,these organic aerogels possess a three-dimensional rigid framework that enhances intersystem crossing(ISC)efficiency and promotes multiple intermolecular interactions,thereby enabling efficient RTP with an ultralong phosphorescent lifetime of up to 1007 ms.Notably,the resulting RTP aerogels demonstrate exceptional structural robustness(compression modulus of 1 MPa),excellent thermal insulation(peak heat release rate reduced to 31.1 kW/m^(2)),and outstanding flame retardancy(limiting oxygen index exceeding 90%),positioning them among the most multifunctional organic aerogels reported to date.Given their balanced combination of RTP performance,mechanical resilience,and thermal stability,these phosphorescent aerogels represent a highly promising platform for the development of advanced,multifunctional organic RTP materials.展开更多
Traditional fluorination strategies have attracted significant attention due to their ability to construct a fluorine-rich solid-electrolyte interphase(SEI)at the anode-electrolyte interface.However,the inhomogeneous ...Traditional fluorination strategies have attracted significant attention due to their ability to construct a fluorine-rich solid-electrolyte interphase(SEI)at the anode-electrolyte interface.However,the inhomogeneous distribution of LiF within the SEI layer remains a critical challenge that hinders the effective suppression of lithium dendrite growth.This work explores the synergy between HDBDPE(degradation products of decabromodiphenyl ethane)and MgF_(2),developing a fluorinated,flame-retardant separator with optimized ion channels,HDBDPE acts as both a low-toxicity flame retardant and an"F-element guide"through hydrogen bonding with MgF_(2),forming a uniform LiF SEI layer on the Li anode for rapid reaction kinetics.Moreover,under thermal runaway conditions,the MgF_(2)@HDBDPE/PP separator constructs a"high-efficiency flame-retardant barrier",effectively quenching free radicals and promoting the formation of MgBr_(2),thereby suppressing electrolyte combustion.As a result,both symmetric and full cells assembled with the MgF_(2)@HDBDPE/PP separator demonstrate superior cyclic stability and rate performance due to improved interfacial reactions.The MgF_(2)@HDBDPE/PP separator exhibits rapid flame retardancy under thermal runaway conditions.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
The development of epoxy(EP)nanocomposites has emerged as a prominent research area across diverse sectors,including automotive,construction,and aerospace industries.Recently,adopting biomimetic strategies for the pre...The development of epoxy(EP)nanocomposites has emerged as a prominent research area across diverse sectors,including automotive,construction,and aerospace industries.Recently,adopting biomimetic strategies for the preparation of nanomaterials to design multifunctional epoxy resins has emerged as a prominent research hotspot.Inspired by the growth pattern of coral reefs,this study successfully engineered a novel hierarchical nanostructured material(Fe-NiPS-PBA)with the aim of creating EP nanocomposites that exhibit highly flame-retardant efficiency,exceptional mechanical strength,and distinguished wear-resisting property even at low additive concentrations.With a 3 wt%addition of Fe-NiPS-PBA,the limiting oxygen index of the EP/3Fe-NiPS-PBA nanocomposite increased from 23.5 to 25.9,achieving a UL-94 V-0 rating.Compared to pure EP,EP/3Fe-NiPSPBA nanocomposite reduced the peak heat release rate(PHRR),total heat release(THR),peak smoke production rate(PSPR),total smoke production(TSP),and maximum CO emission(MCO)by 44.1%,66.7%,47.0%,67.8%,and 51.7%,respectively.Moreover,the incorporation of a 1 wt%additive resulted in significant enhancements of tensile strength from 76.7 MPa to 96.9 MPa,while the wear rate demonstrated a remarkable reduction of 77.8%.The Fe-NiPS-PBA significantly enhanced the fire performance and mechanical strength of EP nanocomposites,demonstrating exceptional overall performance in various applications.展开更多
Nanoscale red phosphorus(NRP)was synthesized via a phosphorus-amine dissolution method and immobilized onto mesoporous silica nanospheres(MSNs)to obtain hybrid NRP@MSN particles with improved dispersion stability.Epox...Nanoscale red phosphorus(NRP)was synthesized via a phosphorus-amine dissolution method and immobilized onto mesoporous silica nanospheres(MSNs)to obtain hybrid NRP@MSN particles with improved dispersion stability.Epoxy resin(EP)composites containing 2 wt%fillers were prepared to evaluate their thermal and flame-retardant behaviors.Compared with EP,the NRP@MSNs/EP composite significantly enhanced fire safety,resulting in a 52.8%reduction in the peak heat release rate,a 13.9%decrease in total smoke production,and a 165%increase in char yield.Mechanical testing revealed a notable toughening effect under impact loading.The improved flame retardancy originates from the combined nano-barrier effect of MSNs and the catalytic charring and radical-quenching functions of NRP.This work demonstrates an efficient strategy for stabilizing NRP and highlights its strong potential as an environmentally friendly flame retardant for EP systems.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
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
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
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
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
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
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
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
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
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financial support from the Helmholtz Association and the German Federal Ministry of Education and Research(BMBF)within the ExcellBattUlm project(03XP0257D)the HighSafe-3 project(03XP0568A)。
文摘Energy density and safety are two crucial parameters when evaluating lithium-metal batteries(LMBs).Herein,we present an ultralight polymer-based current collector,incorporating flame-retardant materials,designed specifically for thin lithium-metal anodes.Compared to the traditional copper current collector(8.96 mg cm^(-2),10μm thick),the polymer-based current collector(12μm thick)has a significantly lower areal density of 1.41 mg cm^(-2),i.e.,only one-sixth of the copper collector,thus enabling substantially higher energy densities.Accordingly,when employed in Li||NMC_(622)full-cells,the polymer-based current collector enables a specific energy of 449 Wh kg^(-1),representing a notable improvement of about14.5%compared to cells employing a classic copper current collector.The inclusion of Al(OH)_(3) as a flame retardant into the current collector suppresses flammability and,thereby,significantly improves the safety of the resulting LMBs.
基金financially supported by Ministry of Science and Higher Education of the Russian Federation.
文摘A new principle for producing fire-resistant polymer materials with increased deformation properties using a flame retardant not as a heterogeneous additive,but as a thermoplastic flame retardant in a hybrid polymer mixture with a polyhydrocarbon is considered.Hybrid polymer blends of low-molecular ammonium polyphosphate(APP)with an ethylene-vinyl acetate copolymer(EVA)with an APP content of 80 wt%with enhanced deformation properties were obtained by extrusion mixing at various temperatures in the range from 200°C to 250°C.A chemical scheme for the transformations of the components during the formation of the composite is proposed.X-ray diffraction analysis showed the formation of new crystalline structures of APP.The phase structure of the systems corresponding to the model of a dispersed-filled composite in which EVA plays the role of a matrix,determining the deformation of the mixture,and the filler is ammonium polyphosphate,was studied by scanning electron microscopy(SEM).The method of FTIR microscopy showed chemical interactions between EVA and APP with the formation of amide groups.The conditions for obtaining compositions characterized by heat resistance of 210°C,oxygen index of 55 and ultimate elongation at drawing of 213%were established.
基金financially supported by the National Key Research and Development Program of China(No.2021YFB3700300)the National Natural Science Foundation of China(Nos.52573017 and U21B2093)+1 种基金Key Research and Development Program of Ningbo(No.2022Z200)the Zhejiang Provincial Natural Science Foundation(No.LY23E030005)。
文摘Bio-based 2,5-furandicarboxylic acid polyesters offer significant promise for reducing energy and environmental crises.However,their intrinsic flammability remains a critical limitation,and conventional flame-retardant strategies often compromise their mechanical properties,hindering their practical applications.Herein,a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO)-based comonomer(DDP)was used to synthesize flame-retardant poly(ethylene furandicarboxylate-co-phosphaphenanthrene)(PEFDn).The covalent integration of DDP confers intrinsic flame retardancy,avoiding the plasticization and migration issues associated with additive-type systems.Upon thermal decomposition,the DOPO-derived moieties release phosphoric acid and radical scavengers,promoting char formation and suppressing flame propagation.Furthermore,density functional theory(DFT)calculations combined with non-covalent interaction(NCI)analysis revealed that DOPO dimer molecules adopt a stable parallel-displaced π-π stacking configu ration,potentially facilitating microphase separation and enhancing the energy dissipation capability.PEFD_(10)achieves a UL-94 V-0 rating while simultaneously increasing impact toughness from 1.5 kJ/m^(2) to 14.7 kJ/m^(2).Im portantly,PEFDn maintained acceptable oxygen-barrier properties.PEFD10 also exhibited high transparency and UV-shielding performance.The combination of intrinsic flame safety,im pact-toughness resistance,UV shielding,and an oxygen barrier ensures reliable protection of electrical components and long-term operational stability.The integration of multiple critical properties within a single bio-based material represents a novel approach fo r enabling sustainable polymer solutions for high-pe rformance electrical applications.
文摘Although poly(urethane-urea)elastomers(PUEs)possess excellent mechanical properties and durability,their inherent flammability and inability to self-repair after damage significantly limits their applications in high-end fields.To address this challenge,this study employs a supramolecular chemistry approach by simultaneously incorporating multiple hydrogen bonds as dynamic cross-linking points and a phosphorus-nitrogen synergistic flame-retardant structure into the poly(urethane-urea)network.The multiple hydrogen bonds endow the material with efficient intrinsic self-healing capability,while the phosphorus-nitrogen flame retardant ensures outstanding thermal stability and flame resistance,leading to the successful synthesis of a high-performance multifunctional poly(urethane-urea)elastomer.Experimental results demonstrated that when the content of the flame retardant diethyl(2-((2-aminoethyl)amino)ethyl)phosphoramidate(DEPTA)was 10 wt%,the resulting PUE/10%DEPTA achieved a V-0 rating in the vertical burning test,with a limiting oxygen index(LOI)of 30%.Concurrently,the elastomer maintained good toughness,exhibiting a tensile strength of 27.3 MPa,an elongation at break of 601%,and a self-healing efficiency of up to 94.46%.This breakthrough shows significant promise for advanced engineering applications that demand fire safety,structural durability,and extended service life through self-repair.
基金financially supported by Natural Science Foundation of Shandong Province(Grant No.ZR2021ME019).
文摘Polyurea(PUA)is widely valued in protective coatings and structural reinforcement because of its impressive mechanical strength and resistance to corrosion.Its high flammability,together with the poor dispersion that often comes with simply blending in flame retardants,continues to limit its use in demanding environments.To overcome these issues,this study introduces a different approach.We grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO)onto the surface of a metal-organic framework(MOF)and then partially amino-functionalized the DOPO layer,ultimately creating an amino-modified DOPO-MOF hybrid.The introduced amino groups can directly react with the isocyanate(-NCO)groups in the PUA matrix,allowing the flame-retardant component to be integrated via reactive integration rather than physical blending.This approach helps avoid the interfacial defects and the mechanical weakening typically observed in conventional blending.With 5 wt% ZIF-67@DOPO-NH2 added to the PUA system,the composite successfully reached a UL-94 V-0 classification and showed a notable increase in limiting oxygen index(LOI),from19.2% to 23.8%.The peak heat release rate and total heat release dropped by 36.3% and 38.7%,respectively.Meanwhile,the tensile strength decreased from 25.74 to 22.52 MPa,while the elongation at break remained above 300%,indicating that the material maintained excellent toughness.
基金supported by the National Natural Science Foundation of China(22475172 and 52203242)the Zhejiang Provincial Natural Science Foundation of China(LQ23B020004)the Fundamental Research Funds for the Central Universities.
文摘Gel-based room-temperature phosphorescence(RTP)materials have garnered significant attention due to their promising applications in flexible electronics and photonics.However,the inherent swollen state and porous architecture of such gels often promote intense molecular motion and facilitate oxygen diffusion,which can severely quench phosphorescence under ambient conditions.In this work,we report a versatile strategy for constructing high-performance organic RTP materials by leveraging organic aerogels,which exhibit superior luminescent,mechanical,and thermal properties.Owing to their structural advantages,these organic aerogels possess a three-dimensional rigid framework that enhances intersystem crossing(ISC)efficiency and promotes multiple intermolecular interactions,thereby enabling efficient RTP with an ultralong phosphorescent lifetime of up to 1007 ms.Notably,the resulting RTP aerogels demonstrate exceptional structural robustness(compression modulus of 1 MPa),excellent thermal insulation(peak heat release rate reduced to 31.1 kW/m^(2)),and outstanding flame retardancy(limiting oxygen index exceeding 90%),positioning them among the most multifunctional organic aerogels reported to date.Given their balanced combination of RTP performance,mechanical resilience,and thermal stability,these phosphorescent aerogels represent a highly promising platform for the development of advanced,multifunctional organic RTP materials.
基金financially supported by the National Natural Science Foundation of China(52401283)National Natural Science Foundation of Jiangsu Province(BK20230933)+1 种基金Fundamental Research Funds for the Central Universities(No.30925010524)Young Faculty Development Fund of Nanjing University of Science and Technology。
文摘Traditional fluorination strategies have attracted significant attention due to their ability to construct a fluorine-rich solid-electrolyte interphase(SEI)at the anode-electrolyte interface.However,the inhomogeneous distribution of LiF within the SEI layer remains a critical challenge that hinders the effective suppression of lithium dendrite growth.This work explores the synergy between HDBDPE(degradation products of decabromodiphenyl ethane)and MgF_(2),developing a fluorinated,flame-retardant separator with optimized ion channels,HDBDPE acts as both a low-toxicity flame retardant and an"F-element guide"through hydrogen bonding with MgF_(2),forming a uniform LiF SEI layer on the Li anode for rapid reaction kinetics.Moreover,under thermal runaway conditions,the MgF_(2)@HDBDPE/PP separator constructs a"high-efficiency flame-retardant barrier",effectively quenching free radicals and promoting the formation of MgBr_(2),thereby suppressing electrolyte combustion.As a result,both symmetric and full cells assembled with the MgF_(2)@HDBDPE/PP separator demonstrate superior cyclic stability and rate performance due to improved interfacial reactions.The MgF_(2)@HDBDPE/PP separator exhibits rapid flame retardancy under thermal runaway conditions.
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Outstanding Youth Scientific Research Project in Anhui Province(2022AH020055)Key Research and Development Projects in Anhui Province(2022i01020016)。
文摘The development of epoxy(EP)nanocomposites has emerged as a prominent research area across diverse sectors,including automotive,construction,and aerospace industries.Recently,adopting biomimetic strategies for the preparation of nanomaterials to design multifunctional epoxy resins has emerged as a prominent research hotspot.Inspired by the growth pattern of coral reefs,this study successfully engineered a novel hierarchical nanostructured material(Fe-NiPS-PBA)with the aim of creating EP nanocomposites that exhibit highly flame-retardant efficiency,exceptional mechanical strength,and distinguished wear-resisting property even at low additive concentrations.With a 3 wt%addition of Fe-NiPS-PBA,the limiting oxygen index of the EP/3Fe-NiPS-PBA nanocomposite increased from 23.5 to 25.9,achieving a UL-94 V-0 rating.Compared to pure EP,EP/3Fe-NiPSPBA nanocomposite reduced the peak heat release rate(PHRR),total heat release(THR),peak smoke production rate(PSPR),total smoke production(TSP),and maximum CO emission(MCO)by 44.1%,66.7%,47.0%,67.8%,and 51.7%,respectively.Moreover,the incorporation of a 1 wt%additive resulted in significant enhancements of tensile strength from 76.7 MPa to 96.9 MPa,while the wear rate demonstrated a remarkable reduction of 77.8%.The Fe-NiPS-PBA significantly enhanced the fire performance and mechanical strength of EP nanocomposites,demonstrating exceptional overall performance in various applications.
基金financially supported by the National Natural Science Foundation of China(Nos.22175167 and 22375195)the Science Fund for Distinguished Young Scholars of Anhui Province(No.2308085J05)This work was also partially carried out at the Instruments Center for Physical Science,University of Science and Technology of China,and partially performed using the services from Scientific Compass(www.shiyanjia.com).
文摘Nanoscale red phosphorus(NRP)was synthesized via a phosphorus-amine dissolution method and immobilized onto mesoporous silica nanospheres(MSNs)to obtain hybrid NRP@MSN particles with improved dispersion stability.Epoxy resin(EP)composites containing 2 wt%fillers were prepared to evaluate their thermal and flame-retardant behaviors.Compared with EP,the NRP@MSNs/EP composite significantly enhanced fire safety,resulting in a 52.8%reduction in the peak heat release rate,a 13.9%decrease in total smoke production,and a 165%increase in char yield.Mechanical testing revealed a notable toughening effect under impact loading.The improved flame retardancy originates from the combined nano-barrier effect of MSNs and the catalytic charring and radical-quenching functions of NRP.This work demonstrates an efficient strategy for stabilizing NRP and highlights its strong potential as an environmentally friendly flame retardant for EP systems.
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(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.
