In the Tibet ancient buildings, there are large amounts of combustible decorative textiles that pose great potential fire hazards. Some typical textile samples were collected from the Potala Palace. Their combustion p...In the Tibet ancient buildings, there are large amounts of combustible decorative textiles that pose great potential fire hazards. Some typical textile samples were collected from the Potala Palace. Their combustion properties were analyzed by UL 94 Vertical Burning test and Limiting Oxygen Index test. The effects of plateau climate on combustion properties, an important fact required to be considered in the flame retarding design for combustible textiles, were preliminarily compared via test data in the plain and those in the plateau. Based on the foregoing analyses, some thoughts were presented on the clean and feasible flame retarding means for the decorative textiles due to their special applications in Tibet, in ancient buildings and in plateau climate. The fire resistance, weather resistance, UV resistance, endurance, ornamentation and religious performances for these textiles must be taken into considerations comprehensively in the designs.展开更多
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
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
The synthesis of reaction flame retarding unsaturated polyester resin and the flame retarding mechanism are investigated.By taking the synthesis flame retarding unsaturated polyester resin as a base material,glass fib...The synthesis of reaction flame retarding unsaturated polyester resin and the flame retarding mechanism are investigated.By taking the synthesis flame retarding unsaturated polyester resin as a base material,glass fibers as reinforced material,under the condition of adding graphite or carbon black respectively,the composites were manufactured.The flame retarding and antistatic properties are also studied.In the experiment,bromide-bearing flame retarding resin decomposed under a high temperature.Compound HBr was set out and retarded or stopped the flame.High concentration of HBr gas wall was formed between gas and solid phrases,which decreased flame.The results show that antistatic property of carbon black is higher than that of graphite.Adding a threshed value of 1% carbon black into composite,the antistatic property is at its highest value.展开更多
Flame-retardant composites with high electromagnetic interference(EMI)shielding performance are desirable for electronic device packaging.Despite great potential of MXene for high EMI,it still remains a great challeng...Flame-retardant composites with high electromagnetic interference(EMI)shielding performance are desirable for electronic device packaging.Despite great potential of MXene for high EMI,it still remains a great challenge to develop high-performance flame-retardant polymer/MXene composites with excellent EMI shielding effectiveness because of the poor oxidative stability of MXene.Herein,phosphorylated MXene/polypropylene(PP)composites are prepared by coating phosphorylated MXene on PP fabric followed by spraying polyethylenimine(PEI)and hot-pressing.The phosphorylated MXene proves to be more durable against oxidation than pure MXene due to the protection effect of polyphosphates.Upon hot-pressing,melted PP fibers are fused together at their contact points and thus as-prepared composites are bi-continuous with two interpenetrating phases.The composites show significantly improved thermal stability and flame retardancy relative to pure PP,with a low total heat release(THR)of 3.7 kJ/g and a heat release rate(HRR)of 50.0 W/g,which are reduced by 78%and 87%,respectively.In addition,the composites exhibit a high electrical conductivity of~36,700 S/m and an EMI shielding performance of~90 d B over the whole frequency range of 8–12 GHz with a thickness of~400μm.The as-developed PP/MXene composites hold great promise for reliable protection of next-generation electronic devices working in complex environments.展开更多
Polymeric organic battery materials are promising alternatives to the transition-metal-based ones owing to their enriched chemistries. However, the flammability of organic compounds brings in serious concern on batter...Polymeric organic battery materials are promising alternatives to the transition-metal-based ones owing to their enriched chemistries. However, the flammability of organic compounds brings in serious concern on battery safety. In addition to use flame-retarding electrolyte/electrolyte additives or battery separators,flame retardancy can readily be achieved through the integration of flame-retarding unit into the polymer backbone, imparting the flame retardancy permanently. The as-designed polymer based on phenothiazine shows significantly shortened self-extinguished time without deteriorating its intrinsic thermodynamic and electrochemical properties. Moreover, two electron per phenothiazine molecule is realized for the first time in a highly reversible manner with discharge voltages of 3.52 V and 4.16 V versus Li+/Li and an average capacity of ca. 120 mAh g-1 at a current rate of 2 C. The origin of the reversibility is investigated through density functional theory(DFT) calculations. These findings address the importance of molecular design for safer and more stable organic materials for batteries.展开更多
The unparalleled energy density has granted lithium-sulfur batteries(LSBs)with attractive usages.Unfortunately,LSBs still face some unsurpassed challenges in industrialization,with polysulfides shuttling,dendrite grow...The unparalleled energy density has granted lithium-sulfur batteries(LSBs)with attractive usages.Unfortunately,LSBs still face some unsurpassed challenges in industrialization,with polysulfides shuttling,dendrite growth and thermal hazard as the major problems triggering the cycling instability and low safety.With the merit of convenience,the method of designing functional separator has been adapted.Concretely,the carbon aerogel confined with CoS_(2)(CoS_(2)-NCA)is constructed and coated on Celgard separator surface,acquiring CoS_(2)-NCA modified separator(CoS_(2)-NCA@C),which holds the promoted electrolyte affinity and flame retardance.As revealed,CoS_(2)-NCA@C cell gives a high discharge capacity 1536.9 mAh/g at 1st cycle,much higher than that of Celgard cell(987.1 mAh/g).Moreover,the thermal runaway triggering time is dramatically prolonged by 777.4 min,corroborating the promoted thermal safety of cell.Noticeably,the higher coulombic efficiency stability and lower overpotential jointly confirm the efficacy of CoS_(2)-NCA@C in suppressing the lithium dendrite growth.Overall,this work can provide useful inspirations for designing functional separator,coping with the vexing issues of LSBs.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
Silicone rubber(SR)exhibits superior breathability and high-temperature resistance.However,SR is prone to degradation under extreme heat or combustion,limiting its effectiveness in mitigating secondary hazards.In this...Silicone rubber(SR)exhibits superior breathability and high-temperature resistance.However,SR is prone to degradation under extreme heat or combustion,limiting its effectiveness in mitigating secondary hazards.In this study,phosphate glass powder was used to calcinate zinc borate,lanthanum oxide,and cerium oxide.Methylphenyl polysiloxane was then grafted onto the surface of the glass powder,resulting in the modified pow-ders designated as Methylphenyl polysiloxane-grafted zinc borate-modified phosphate glass powder(GF-ZnBM),Methylphenyl polysiloxane-grafted lanthanum oxide-modified phosphate glass powder(GF-LaM),and Methylphenyl polysiloxane-grafted cerium oxide-modified phosphate glass powder(GF-CeM).The modified powders were sub-sequently incorporated into silicone rubber composites to enhance the ceramicization capability of silicone rubber at high temperatures.Specifically,GF-CeM and GF-LaM significantly increased the limiting oxygen index(LOI)to 33%and reduced the tendency for combustion propagation.Additionally,GF-CeM notably contributed to enhancing ceramicization strength.The presence of cerium oxide helps in the melting of the glass powder and enhances its adhesion to the silicone rubber matrix.SR/ZnB-GF exhibited the lowest activation energy among the tested composites,along with the best protective capability.The inclusion of modified glass powder has a minor impact on the rheological properties,indicating that the composite retains its ability to flow and deform under stress.This confirms that the material remains flexible under normal conditions and forms a ceramic structure when heated,thereby exhibiting self-supporting properties.This study provides a practical methodology for the targeted modification of glass powders,thereby further enhancing the fire safety of silicone-based composites.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
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
The global automotive sector is moving towards zero-emission transportation,which has led to the rapid growthof the electric vehidles(EVs)market,projected to reach USD1,318 billion in 2028.However,behind the booming d...The global automotive sector is moving towards zero-emission transportation,which has led to the rapid growthof the electric vehidles(EVs)market,projected to reach USD1,318 billion in 2028.However,behind the booming develop-ment of the electric vehicle market,its safety issues havealways been the focal point of consumers'concern and alsothe cornerstone for the sustained and healthy developmentof the new energy vehicle industry.展开更多
The fabrication of highly flame-retardant polyamide 6(PA6)composites is of great significance for expanding their practical applications.Herein,a new flame-retardant system(ADP/FA)was developed by combining aluminum d...The fabrication of highly flame-retardant polyamide 6(PA6)composites is of great significance for expanding their practical applications.Herein,a new flame-retardant system(ADP/FA)was developed by combining aluminum diethylphosphinate(ADP)with excellent flame retardancy and fly ash(FA),an economical and environmentally friendly industrial waste.Due to the synergistic flame-retardant effect of ADP/FA in the condensed phase and gas phase,the PA6 composite containing only 11 wt%of ADP/FA(mass ratio 93:7)obtained vertical burning(UL-94)tests V-0 rating with a limiting oxygen index(LOI)of 30.9%.To obtain the same flame-retardant level of PA6/ADP/FA-3,the loading amount of ADP alone was required 14 wt%.Compared with the PA6/ADP,the introduction of FA not only reduced the amount of flame retardant added but also inhibited the formation of molten droplets during combustion,greatly enhancing the fire safety of the PA6 composites.The flame-retardant performance of the ADP/FA system is superior to that of most current ADP-based synergistic strategies.In the meantime,the introduction of FA also significantly reduced the high smoke release caused by ADP flame retardant.The peak smoke production rate(pSPR)of the PA6 composite,from 0.221 m2⋅s-1(PA6/ADP)to 0.116 m2⋅s-1,represents a 47.5%decrease.This work provides a feasible solution for fabricating PA6 composites with excellent flame retardancy.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
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
文摘In the Tibet ancient buildings, there are large amounts of combustible decorative textiles that pose great potential fire hazards. Some typical textile samples were collected from the Potala Palace. Their combustion properties were analyzed by UL 94 Vertical Burning test and Limiting Oxygen Index test. The effects of plateau climate on combustion properties, an important fact required to be considered in the flame retarding design for combustible textiles, were preliminarily compared via test data in the plain and those in the plateau. Based on the foregoing analyses, some thoughts were presented on the clean and feasible flame retarding means for the decorative textiles due to their special applications in Tibet, in ancient buildings and in plateau climate. The fire resistance, weather resistance, UV resistance, endurance, ornamentation and religious performances for these textiles must be taken into considerations comprehensively in the designs.
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 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.
文摘The synthesis of reaction flame retarding unsaturated polyester resin and the flame retarding mechanism are investigated.By taking the synthesis flame retarding unsaturated polyester resin as a base material,glass fibers as reinforced material,under the condition of adding graphite or carbon black respectively,the composites were manufactured.The flame retarding and antistatic properties are also studied.In the experiment,bromide-bearing flame retarding resin decomposed under a high temperature.Compound HBr was set out and retarded or stopped the flame.High concentration of HBr gas wall was formed between gas and solid phrases,which decreased flame.The results show that antistatic property of carbon black is higher than that of graphite.Adding a threshed value of 1% carbon black into composite,the antistatic property is at its highest value.
基金funding support of the Key Laboratory of Flame Retardancy Finishing of Textile Materials,CNTAC(Q811580421)Australian Research Council(Nos.DP190102992 and FT190100188)the National Natural Science Foundation of China(Nos.51803200 and 52003104)。
文摘Flame-retardant composites with high electromagnetic interference(EMI)shielding performance are desirable for electronic device packaging.Despite great potential of MXene for high EMI,it still remains a great challenge to develop high-performance flame-retardant polymer/MXene composites with excellent EMI shielding effectiveness because of the poor oxidative stability of MXene.Herein,phosphorylated MXene/polypropylene(PP)composites are prepared by coating phosphorylated MXene on PP fabric followed by spraying polyethylenimine(PEI)and hot-pressing.The phosphorylated MXene proves to be more durable against oxidation than pure MXene due to the protection effect of polyphosphates.Upon hot-pressing,melted PP fibers are fused together at their contact points and thus as-prepared composites are bi-continuous with two interpenetrating phases.The composites show significantly improved thermal stability and flame retardancy relative to pure PP,with a low total heat release(THR)of 3.7 kJ/g and a heat release rate(HRR)of 50.0 W/g,which are reduced by 78%and 87%,respectively.In addition,the composites exhibit a high electrical conductivity of~36,700 S/m and an EMI shielding performance of~90 d B over the whole frequency range of 8–12 GHz with a thickness of~400μm.The as-developed PP/MXene composites hold great promise for reliable protection of next-generation electronic devices working in complex environments.
基金financial support from the National Natural Science Foundation of China (grant no.51772199)the Natural Science Foundation of Jiangsu Province (Grant no.BK20170329)+2 种基金the Collaborative Innovation Center of Suzhou Nano Science & Technologythe Priority Academic Program Development of Jiangsu Higher Education Institutionsthe 111 Project。
文摘Polymeric organic battery materials are promising alternatives to the transition-metal-based ones owing to their enriched chemistries. However, the flammability of organic compounds brings in serious concern on battery safety. In addition to use flame-retarding electrolyte/electrolyte additives or battery separators,flame retardancy can readily be achieved through the integration of flame-retarding unit into the polymer backbone, imparting the flame retardancy permanently. The as-designed polymer based on phenothiazine shows significantly shortened self-extinguished time without deteriorating its intrinsic thermodynamic and electrochemical properties. Moreover, two electron per phenothiazine molecule is realized for the first time in a highly reversible manner with discharge voltages of 3.52 V and 4.16 V versus Li+/Li and an average capacity of ca. 120 mAh g-1 at a current rate of 2 C. The origin of the reversibility is investigated through density functional theory(DFT) calculations. These findings address the importance of molecular design for safer and more stable organic materials for batteries.
基金financially supported by the National Natural Science Foundation of China(52104197)Hongkong Scholar Program(XJ2022022)+5 种基金National Science Foundation for Post-doctoral Scientists of China(2021M691549,2021M703082)National Natural Science Foundation of China(52272396,52306090)Jiangsu Provincial Double-Innovation Doctor Program(JSSCBS20210402)Natural Science Foundation of the Jiangsu Higher Education Institutions(21KJB620001)The Open Fund of the State Key Laboratory of Fire Science(SKLFS)Program(HZ2022-KF04)Postgraduate Research&Practice Innovation Program of Jiangsu Province(SJCX22-0457)。
文摘The unparalleled energy density has granted lithium-sulfur batteries(LSBs)with attractive usages.Unfortunately,LSBs still face some unsurpassed challenges in industrialization,with polysulfides shuttling,dendrite growth and thermal hazard as the major problems triggering the cycling instability and low safety.With the merit of convenience,the method of designing functional separator has been adapted.Concretely,the carbon aerogel confined with CoS_(2)(CoS_(2)-NCA)is constructed and coated on Celgard separator surface,acquiring CoS_(2)-NCA modified separator(CoS_(2)-NCA@C),which holds the promoted electrolyte affinity and flame retardance.As revealed,CoS_(2)-NCA@C cell gives a high discharge capacity 1536.9 mAh/g at 1st cycle,much higher than that of Celgard cell(987.1 mAh/g).Moreover,the thermal runaway triggering time is dramatically prolonged by 777.4 min,corroborating the promoted thermal safety of cell.Noticeably,the higher coulombic efficiency stability and lower overpotential jointly confirm the efficacy of CoS_(2)-NCA@C in suppressing the lithium dendrite growth.Overall,this work can provide useful inspirations for designing functional separator,coping with the vexing issues of LSBs.
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 National Natural Science Foundation of China(51991352 and 51874266).
文摘Silicone rubber(SR)exhibits superior breathability and high-temperature resistance.However,SR is prone to degradation under extreme heat or combustion,limiting its effectiveness in mitigating secondary hazards.In this study,phosphate glass powder was used to calcinate zinc borate,lanthanum oxide,and cerium oxide.Methylphenyl polysiloxane was then grafted onto the surface of the glass powder,resulting in the modified pow-ders designated as Methylphenyl polysiloxane-grafted zinc borate-modified phosphate glass powder(GF-ZnBM),Methylphenyl polysiloxane-grafted lanthanum oxide-modified phosphate glass powder(GF-LaM),and Methylphenyl polysiloxane-grafted cerium oxide-modified phosphate glass powder(GF-CeM).The modified powders were sub-sequently incorporated into silicone rubber composites to enhance the ceramicization capability of silicone rubber at high temperatures.Specifically,GF-CeM and GF-LaM significantly increased the limiting oxygen index(LOI)to 33%and reduced the tendency for combustion propagation.Additionally,GF-CeM notably contributed to enhancing ceramicization strength.The presence of cerium oxide helps in the melting of the glass powder and enhances its adhesion to the silicone rubber matrix.SR/ZnB-GF exhibited the lowest activation energy among the tested composites,along with the best protective capability.The inclusion of modified glass powder has a minor impact on the rheological properties,indicating that the composite retains its ability to flow and deform under stress.This confirms that the material remains flexible under normal conditions and forms a ceramic structure when heated,thereby exhibiting self-supporting properties.This study provides a practical methodology for the targeted modification of glass powders,thereby further enhancing the fire safety of silicone-based composites.
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.
文摘The global automotive sector is moving towards zero-emission transportation,which has led to the rapid growthof the electric vehidles(EVs)market,projected to reach USD1,318 billion in 2028.However,behind the booming develop-ment of the electric vehicle market,its safety issues havealways been the focal point of consumers'concern and alsothe cornerstone for the sustained and healthy developmentof the new energy vehicle industry.
基金financially supported by the Natural Science Foundation of China(52173069)the Key Research and Development Projects in Heilongjiang Province(2024ZXDXA29)+1 种基金the Natural Science Foundation of Heilongjiang Province(LH2024B004)the Fundamental Research Funds for the Central Universities(ZHLJZR241700006).
文摘The fabrication of highly flame-retardant polyamide 6(PA6)composites is of great significance for expanding their practical applications.Herein,a new flame-retardant system(ADP/FA)was developed by combining aluminum diethylphosphinate(ADP)with excellent flame retardancy and fly ash(FA),an economical and environmentally friendly industrial waste.Due to the synergistic flame-retardant effect of ADP/FA in the condensed phase and gas phase,the PA6 composite containing only 11 wt%of ADP/FA(mass ratio 93:7)obtained vertical burning(UL-94)tests V-0 rating with a limiting oxygen index(LOI)of 30.9%.To obtain the same flame-retardant level of PA6/ADP/FA-3,the loading amount of ADP alone was required 14 wt%.Compared with the PA6/ADP,the introduction of FA not only reduced the amount of flame retardant added but also inhibited the formation of molten droplets during combustion,greatly enhancing the fire safety of the PA6 composites.The flame-retardant performance of the ADP/FA system is superior to that of most current ADP-based synergistic strategies.In the meantime,the introduction of FA also significantly reduced the high smoke release caused by ADP flame retardant.The peak smoke production rate(pSPR)of the PA6 composite,from 0.221 m2⋅s-1(PA6/ADP)to 0.116 m2⋅s-1,represents a 47.5%decrease.This work provides a feasible solution for fabricating PA6 composites with excellent flame retardancy.
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.
