Gypsum was used as substrate,and silica gel was mixed into substrate at a certain mass ratio to prepare humidity-controlling composites;moreover,the moisture absorption and desorption properties of gypsum-based compos...Gypsum was used as substrate,and silica gel was mixed into substrate at a certain mass ratio to prepare humidity-controlling composites;moreover,the moisture absorption and desorption properties of gypsum-based composites were compared with adding different silica gel particle size and proportion.The morphological characteristics,the isothermal equilibrium moisture content curve,moisture absorption and desorption rate,moisture absorption and desorption stability,and humidity-conditioning performance were tested and analyzed.The experimental results show that,compared with pure-gypsum,the surface structure of the gypsum-based composites is relatively loose,the quantity,density and aperture of the pores in the structure increase.The absorption and desorption capacity increase along with the increase of silica gel particle size and silica gel proportion.When 3 mm silica gel particle size is added with a mass ratio of 40%,the maximum equilibrium moisture content of humidity-controlling composites is 0.161 g/g at 98% relative humidity(RH),3.22 times that of pure-gypsum.The moisture absorption and desorption rates are increased,the equilibrium moisture absorption and desorption rates are 2.68 times and 1.61 times that of pure-gypsum at 58.5% RH,respectively.The gypsum-based composites have a good stability,which has better timely response to dynamic humidity changes and can effectively regulate indoor humidity under natural conditions.展开更多
MXenes are a family of two-dimensional(2D)layered transition metal carbides/nitrides that show promising potential for energy storage applications due to their high-specific surface areas,excellent electron conductivi...MXenes are a family of two-dimensional(2D)layered transition metal carbides/nitrides that show promising potential for energy storage applications due to their high-specific surface areas,excellent electron conductivity,good hydrophilicity,and tunable terminations.Among various types of MXenes,Ti_(3)C_(2)T_(x) is the most widely studied for use in capacitive energy storage applications,especially in supercapacitors(SCs).However,the stacking and oxidation of MXene sheets inevitably lead to a significant loss of electrochemically active sites.To overcome such challenges,carbon materials are frequently incorporated into MXenes to enhance their electrochemical properties.This review introduces the common strategies used for synthesizing Ti_(3)C_(2)T_(x),followed by a comprehensive overview of recent developments in Ti_(3)C_(2)T_(x)/carbon composites as electrode materials for SCs.Ti_(3)C_(2)T_(x)/carbon composites are categorized based on the dimensions of carbons,including 0D carbon dots,1D carbon nanotubes and fibers,2D graphene,and 3D carbon materials(activated carbon,polymer-derived carbon,etc.).Finally,this review also provides a perspective on developing novel MXenes/carbon composites as electrodes for application in SCs.展开更多
The shear behavior of backfill-rock composites is crucial for mine safety and the management of surface subsidence.For exposing the shear failure mechanism of backfill-rock composites,we conducted shear tests on backf...The shear behavior of backfill-rock composites is crucial for mine safety and the management of surface subsidence.For exposing the shear failure mechanism of backfill-rock composites,we conducted shear tests on backfill-rock composites under three constant normal loads,compared with the unfilled rock.To investigate the macro-and meso-failure characteristics of the samples in the shear tests,the cracking behavior of samples was recorded by a high-speed camera and acoustic emission monitoring.In parallel with the experimental test,the numerical models of backfill-rock composites and unfilled rock were established using the discrete element method to analyze the continuous-discontinuous shearing process.Based on the damage mechanics and statistics,a novel shear constitutive model was proposed to describe mechanical behavior.The results show that backfill-rock composites had a special bimodal phenomenon of shearing load-deformation curve,i.e.the first shearing peak corresponded to rock break and the second shearing peak induced by the broken of aeolian sand-cement/fly ash paste backfill.Moreover,the shearing characteristic curves of the backfill-rock composites could be roughly divided into four stages,i.e.the shear failure of the specimens experienced:stage I:stress concentration;stage II:crack propagation;stage III:crack coalescence;stage IV:shearing friction.The numerical simulation shows that the existence of aeolian sand-cement/fly ash paste backfill inevitably altered the coalescence type and failure mode of the specimens and had a strengthening effect on the shear strength of backfillrock composites.Based on damage mechanics and statistics,a shear constitutive model was proposed to describe the shear fracture characteristics of specimens,especially the bimodal phenomenon.Finally,the micro-and meso-mechanisms of shear failure were discussed by combining the micro-test and numerical results.The research can advance the better understanding of the shear behavior of backfill-rock composites and contribute to the safety of mining engineering.展开更多
Polymer dielectrics capable of operating efficiently at high electric fields and elevated temperatures are urgently demanded by next-generation electronics and electrical power systems.While inorganic fillers have bee...Polymer dielectrics capable of operating efficiently at high electric fields and elevated temperatures are urgently demanded by next-generation electronics and electrical power systems.While inorganic fillers have been extensively utilized to improved high-temperature capacitive performance of dielectric polymers,the presence of thermodynamically incompatible organic and inorganic components may lead to concern about the long-term stability and also complicate film processing.Herein,zero-dimensional polymer dots with high electron affinity are introduced into photoactive allyl-containing poly(aryl ether sulfone)to form the all-organic polymer composites for hightemperature capacitive energy storage.Upon ultraviolet irradiation,the crosslinked polymer composites with polymer dots are efficient in suppressing electrical conduction at high electric fields and elevated temperatures,which significantly reduces the high-field energy loss of the composites at 200℃.Accordingly,the ultraviolet-irradiated composite film exhibits a discharged energy density of 4.2 J cm^(−3)at 200℃.Along with outstanding cyclic stability of capacitive performance at 200℃,this work provides a promising class of dielectric materials for robust high-performance all-organic dielectric nanocomposites.展开更多
The severe dependence of traditional phase change materials(PCMs)on the temperature-response and lattice deficiencies in versatility cannot satisfy demand for using such materials in complex application scenarios.Here...The severe dependence of traditional phase change materials(PCMs)on the temperature-response and lattice deficiencies in versatility cannot satisfy demand for using such materials in complex application scenarios.Here,we introduced metal ions to induce the self-assembly of MXene nanosheets and achieve their ordered arrangement by combining suction filtration and rapid freezing.Subsequently,a series of MXene/K^(+)/paraffin wax(PW)phase change composites(PCCs)were obtained via vacuum impregnation in molten PW.The prepared MXene-based PCCs showed versatile applications from macroscale technologies,successfully transforming solar,electric,and magnetic energy into thermal energy stored as latent heat in the PCCs.Moreover,due to the absence of binder in the MXene-based aerogel,MK3@PW exhibits a prime solar-thermal conversion efficiency(98.4%).Notably,MK3@PW can further convert the collected heat energy into electric energy through thermoelectric equipment and realize favorable solar-thermal-electric conversion(producing 206 mV of voltage with light radiation intensity of 200 mw cm^(−2)).An excellent Joule heat performance(reaching 105℃with an input voltage of 2.5 V)and responsive magnetic-thermal conversion behavior(a charging time of 11.8 s can achieve a thermal insulation effect of 285 s)for contactless thermotherapy were also demonstrated by the MK3@PW.Specifically,as a result of the ordered arrangement of MXene nanosheet self-assembly induced by potassium ions,MK3@PW PCC exhibits a higher electromagnetic shielding efficiency value(57.7 dB)than pure MXene aerogel/PW PCC(29.8 dB)with the same MXene mass.This work presents an opportunity for the multi-scene response and practical application of PCMs that satisfy demand of next-generation multifunctional PCCs.展开更多
Stemming from the unique in-plane honeycomb lattice structure and the sp^(2)hybridized carbon atoms bonded by exceptionally strong carbon–carbon bonds,graphene exhibits remarkable anisotropic electrical,mechanical,an...Stemming from the unique in-plane honeycomb lattice structure and the sp^(2)hybridized carbon atoms bonded by exceptionally strong carbon–carbon bonds,graphene exhibits remarkable anisotropic electrical,mechanical,and thermal properties.To maximize the utilization of graphene’s in-plane properties,pre-constructed and aligned structures,such as oriented aerogels,films,and fibers,have been designed.The unique combination of aligned structure,high surface area,excellent electrical conductivity,mechanical stability,thermal conductivity,and porous nature of highly aligned graphene aerogels allows for tailored and enhanced performance in specific directions,enabling advancements in diverse fields.This review provides a comprehensive overview of recent advances in highly aligned graphene aerogels and their composites.It highlights the fabrication methods of aligned graphene aerogels and the optimization of alignment which can be estimated both qualitatively and quantitatively.The oriented scaffolds endow graphene aerogels and their composites with anisotropic properties,showing enhanced electrical,mechanical,and thermal properties along the alignment at the sacrifice of the perpendicular direction.This review showcases remarkable properties and applications of aligned graphene aerogels and their composites,such as their suitability for electronics,environmental applications,thermal management,and energy storage.Challenges and potential opportunities are proposed to offer new insights into prospects of this material.展开更多
A new,innovative vibration cast-rolling technology of “electromagnetic stirring+dendrite breaking+asynchronous rolling” was proposed with the adoption of sinusoidal vibration of crystallization roller to prepare Ti/...A new,innovative vibration cast-rolling technology of “electromagnetic stirring+dendrite breaking+asynchronous rolling” was proposed with the adoption of sinusoidal vibration of crystallization roller to prepare Ti/Al laminated composites,and the effect of sinusoidal vibration of crystallization roller on composite microstructure was investigated in detail.The results show that the metallurgical bonding of titanium and aluminum is realized by mesh interweaving and mosaic meshing,instead of transition bonding by forming metal compound layer.The meshing depth between titanium and aluminum layers (6.6μm) of cast-rolling materials with strong vibration of crystallization roller (amplitude 0.87 mm,vibration frequency 25 Hz) is doubled compared with that of traditional cast-rolling materials (3.1μm),and the composite interfacial strength(27.0 N/mm) is twice as high as that of traditional cast-rolling materials (14.9 N/mm).This is because with the action of high-speed superposition of strong tension along the rolling direction,strong pressure along the width direction and rolling force,the composite linearity evolves from "straight line" with traditional casting-rolling to "curved line",and the depth and number of cracks in the interface increases greatly compared with those with traditional cast-rolling,which leads to the deep expansion of the meshing area between interfacial layers and promotes the stable enhancement of composite quality.展开更多
Recently,ZnO-based composites have been widely applied in the field of electric power.To meet the diverse application requirements,it is necessary to figure out the I-V characteristics of ZnO composites whose high-vol...Recently,ZnO-based composites have been widely applied in the field of electric power.To meet the diverse application requirements,it is necessary to figure out the I-V characteristics of ZnO composites whose high-voltage and ground-voltage electrodes are arranged on the opposite sides with a certain horizontal distance.30 vol%,40 vol%and 50 vol%ZnO-based silicone rubber composites were prepared.The horizontal distance between their electrodes was set as 50,100,500μm,1 and 2 mm,respectively.Results showed that with the increase of ZnO fillers volume fraction under a fixed horizontal distance of 100μm,from 30 vol%to 50 vol%,the I-V curves shifted left,the leakage current increased and the switching voltage decreased.When the horizontal distance between electrodes increased from 50μm to 1 mm under a fixed doping concentration of 40%,the I-V curves shifted to the right,the leakage current dropped and the switching voltage rose.The mathematical and physical models were established to explain the results.This work provides a referential significance for the practical application of ZnO composites,such as 5G folding mobile phones and power electronic modules.展开更多
Surface flashover is a crucial issue for the miniaturisation of electronic facilities in military,industrial,and aerospace engineering.The oriented hexagonal boron nitride(hBN)composites,due to excellent thermal and e...Surface flashover is a crucial issue for the miniaturisation of electronic facilities in military,industrial,and aerospace engineering.The oriented hexagonal boron nitride(hBN)composites,due to excellent thermal and electrical insulating properties,show a potential application in high-voltage power equipment,while the surface flashover performance of hBN composites dependent on oriented hBN texture is rarely reported.The effects of hBN orientation and contents on the surface flashover performances of oriented hBN composites are investigated.The isothermal surface potential decay of the oriented hBN composites was also studied.It is found that the charge transportation could be adjusted by the hBN orientation,thus regulating surface flashover strength.The DC flashover voltage of the in-plane oriented hBN composites with a thickness of 15μm reached the maximum of 27.6 kV at the hBN loading of 20 wt%,14.5%higher than that of the pure resin.The carrier mobility of out-of-plane oriented hBN composites is about three times greater than that of the in-plane oriented composites,indicating that the charges are easily transported along the hBN basal plane.The larger carrier mobility causes charge dissipation in composites near the electrode at the hBN basal plane parallel to the axis of electrodes and inhibits the distortion of the surface electric field on the composites,thus enhancing the surface flashover.Consequently,developing oriented insulators for highvoltage applications and enabling an optimum insulation design would be beneficial because of the compactness and high reliability of power apparatus for use in power grids.展开更多
Materials with both large magnetocaloric response and high thermoelectric performance are of vital importance for all-solid-state thermoelectromagnetic cooling.These two properties,however,hardly coexist in single pha...Materials with both large magnetocaloric response and high thermoelectric performance are of vital importance for all-solid-state thermoelectromagnetic cooling.These two properties,however,hardly coexist in single phase materials except previously reported hexagonal Cr_(1-x)Te half metal where a relatively high magnetic entropy change(-△S_(M))of~2.4 J·kg^(-1)·K^(-1)@5 T and a moderate thermoelectric figure of merit(ZT)of~1.2×10^(-2)@300 K are simultaneously recorded.Herein we aim to increase the thermoelectric performance of Cr_(1-x)Te by compositing with semiconducting Ag_(2)Te.It is discovered that the in-situ synthesis of Cr_(1-x)Te/Ag_(2)Te composites by reacting their constitute elements above melting temperatures is unsuccessful because of strong phase competition.Specifically,at elevated temperatures(T>800 K),Cr_(1-x)Te has a much lower deformation energy than Ag_(2)Te and tends to become more Cr-deficient by capturing Te from Ag_(2)Te.Therefore,Ag is insufficiently reacted and as a metal it deteriorates ZT.We then rationalize the synthesis of Cr_(1-x)Te/Ag_(2)Te composites by ex-situ mix of the pre-prepared Cr_(1-x)Te and Ag_(2)Te binary compounds followed by densification at a low sintering temperature of 573 K under a pressure of 3.5 GPa.We show that by compositing with 7 mol%Ag_(2)Te,the Seebeck coefficient of Cr_(1-x)Te is largely increased while the lattice thermal conductivity is considerably reduced,leading to 72%improvement of ZT.By comparison,-△S_(M)is only slightly reduced by 10%in the composite.Our work demonstrates the potential of Cr_(1-x)Te/Ag_(2)Te composites for thermoelectromagnetic cooling.展开更多
In order to explore the thermal conductivity of polypropylene(PP)/hexagonal boron nitride(BN) composites,PP composites filled with different proportions of BN were prepared through extrution compounding,injection moul...In order to explore the thermal conductivity of polypropylene(PP)/hexagonal boron nitride(BN) composites,PP composites filled with different proportions of BN were prepared through extrution compounding,injection moulding and compression moulding.The composites were filled with BN particles of 5 and 20 μm respectively,and their mass fractions in composites were considered.Percentage of BN was varied from 0 to 25wt% in steps of 5wt%.The effects of BN filler on mechanical properties of the composites were evaluated.The thermal behaviors were studied using DSC and TGA,and the thermal conductivity was also investigated by Laser Flash Device and the Model of 3D Heat Conduction respectively.The experimental results show that impact strength of PP/BN can be enhanced with the addition of BN,but that composites exhibit lower breaking elongation & tensile strength when compared to unfilled ones.It is found that mass fraction of BN influenced the final thermal stability and degree of crystallization of PP matrix,the degree of crystallization of PP with 15wt% of 20 μm BN can be improved by 25% than neat PP.Meanwhile,crystallization temperatures of PP composites are elevated by about 10 ℃.The thermal conductivity results demonstrate that the maximum value of the thermal conductivity is achieved from PP/BN with 20wt% of 20 μm BN,higher than that of pure PP by 95.65%,close to the simulation one.展开更多
Magnesium matrix composites have garnered significant attention in recent years owing to their exceptional lightweight properties and notable potential in various engineering applications.The interface generally acts ...Magnesium matrix composites have garnered significant attention in recent years owing to their exceptional lightweight properties and notable potential in various engineering applications.The interface generally acts as a“bridge”between the matrix and reinforcement,playing crucial roles in critical processes such as load transfer,failure behavior,and carrier transport.A deep understanding of the interfacial structures,properties,and effects holds paramount significance in the study of composites.This paper presents a comprehensive review of prior researches related to the interface of Mg matrix composites.Firstly,the different interfacial structures and interaction mechanisms encompassing mechanical,physical,and chemical bonding are introduced.Subsequently,the interfacial mechanical properties and their influence on the overall properties are discussed.Finally,the paper addresses diverse interface modification methods including matrix alloying and reinforcement surface treatment.展开更多
Titanium matrix composites reinforced with ceramic particles are considered a promising engineering material due to their combination of high specific strength,low density,and high modulus.In this study,the TA15-based...Titanium matrix composites reinforced with ceramic particles are considered a promising engineering material due to their combination of high specific strength,low density,and high modulus.In this study,the TA15-based composites reinforced with a volume fraction of 10% to 25%(TiB+TiC)were prepared using powder metallurgy and casting technique.Microstructural characterization and phase constitution were examined using optical microscopy(OM),scanning electron microscopy(SEM),and X-ray diffraction(XRD).In addition,the microhardness,room temperature(RT)and high temperature(HT)tensile properties of the composites were evaluated.Results revealed that the reinforcements are distributed uniformly even in the composites with a high volume of TiB and TiC.However,as the volume fraction exceeds 15%,TiB and TiC particles become coarsening and exhibit rod-like and dendritic-like morphology.Microhardness increases gradually from 321.2 HV for the base alloy to a maximum of 473.3 HV as the reinforcement increases to 25vol.%.Tensile test results indicate that a reinforcement volume fraction above 20% is beneficial for enhancing tensile strength and yield strength at high temperatures,but it has an adverse effect on room temperature elongation.Conversely,if the reinforcement volume fraction is below 20%,it can improve high-temperature elongation when the temperature exceeds 600℃.展开更多
Bark extracts are sustainable sources of biopolymers and hold great promise for replacing fossil fuel-based polymers,for example,in wood-based composites.In addition to primary and secondary metabolites,tree bark also...Bark extracts are sustainable sources of biopolymers and hold great promise for replacing fossil fuel-based polymers,for example,in wood-based composites.In addition to primary and secondary metabolites,tree bark also contains suberin,which plays a major role in protecting the tree from environmental conditions.Suberin is a natural aliphatic-aromatic cross-linked polyester present in the cell walls of both normal and damaged external tissues,the main component of which are long-chain aliphatic acids.Its main role as a plant ingredient is to protect against microbiological factors and water loss.One of the most important suberin monomers are suberin fatty acids,known for their hydrophobic and barrier properties.Therefore,due to the diverse chemical composition of suberin,it is an attractive alternative to hydrocarbon-based materials.Although its potential is recognized,it is not widely used in biocomposites technology,including wood-based composites and the polymer industry.The article will discuss the current knowledge about the potential of suberin and its components in biocomposites technology,which will include surface finishes,composite adhesives and polymer blends.展开更多
Realising the potential of Magnesium(Mg),several globally leading ventures have invested in the Mg industry,but their relatively poor corrosion resistance is a never ending saga till date.The corrosion and bio-corrosi...Realising the potential of Magnesium(Mg),several globally leading ventures have invested in the Mg industry,but their relatively poor corrosion resistance is a never ending saga till date.The corrosion and bio-corrosion behaviour of Mg has gained research attention and still remains a hot topic in the application of automobile,aerospace and biomedical industries.The intrinsic high electrochemical nature of Mg limits their utilization in diverse application.This scenario has prompted the development of Mg composites with an aim to achieve superior corrosion and bio-corrosion resistance.The present review enlightens the influence of grain size(GS),secondary phase,texture,type of matrix and reinforcement on the corrosion and bio-corrosion behaviour of Mg composites.Firstly,the corrosion and bio-corrosion behaviour of Mg composites manufactured by primary and secondary processing routes are elucidated.Secondly,the comprehensive corrosion and bio-corrosion mechanisms of these Mg composites are proposed.Thirdly,the individual role of GS,texture and corrosive medium on corrosion and bio-corrosion behaviour of Mg composites are clarified and revealed.The challenges encountered,unanswered issues in this field are explained in detail and accordingly the scope for future research is framed.The review is presented from basic concrete background to advanced corrosion mechanisms with an aim of creating interest among the readers like students,researchers and industry experts from various research backgrounds.Indeed,the corrosion and bio-corrosion behaviour of Mg composites are critically reviewed for the first time to:(i)contribute to the body of knowledge,(ii)foster research and development,(iii)make breakthrough,and(iv)create life changing innovations in the field of Mg composite corrosion.展开更多
With the rapid development of science and technology,electronic devices are moving towards miniaturization and integration,which brings high heat dissipation requirements.During the heat dissipation process of a heati...With the rapid development of science and technology,electronic devices are moving towards miniaturization and integration,which brings high heat dissipation requirements.During the heat dissipation process of a heating element,heat may spread to adjacent components,causing a decrease in the performance of the element.To avoid this situation,the ability to directionally transfer heat energy is urgently needed.Therefore,thermal interface materials(TIMs)with directional high thermal conductivity are more critical in thermal management system of electronic devices.For decades,many efforts have been devoted to the design and fabrication of TIMs with high-directional thermal conductivity.Benefiting from the advantage in feasibility,low-cost and scalability,compositing with thermal conductive fillers has been proved to be promising strategy for fabricating the high-directional thermal conductive TIMs.This review summarizes the present preparation technologies of polymer composites with high-directional thermal conductivity based on structural engineering of thermal conductive fillers,focusing on the manufacturing process,mechanisms,achievements,advantages and disadvantages of different technologies.Finally,we summarize the existing problems and potential challenges in the field of directional high thermal conductivity composites.展开更多
The lack of soft magnetic composites with high power density in MHz frequency range has become an obstacle in the efficient operation of the electrical and electronic equipments.Here,a promising method to increase the...The lack of soft magnetic composites with high power density in MHz frequency range has become an obstacle in the efficient operation of the electrical and electronic equipments.Here,a promising method to increase the cut-off frequency of iron-based soft magnetic composites to hundreds of MHz is reported.The cut-off frequency is increased from 10 MHz to 1 GHz by modulating the height of the ring,the distribution of particles,and the particle size.The mechanism of cut-off frequency and permeability is the coherent rotation of domain modulated by inhomogeneous field due to the eddy current effect.An empirical formula for the cut-off frequency in a magnetic ring composed of iron-based particles is established from experimental data.This work provides an effective approach to fabricate soft magnetic composites with a cut-off frequency in hundreds of MHz.展开更多
Polyacrylic acid(PAA)hydrogel composites with different hexagonal boron nitride(h-BN)fillers were synthesized and successfully 3D-printed while their thermal conductivity was systematically studied.With the content of...Polyacrylic acid(PAA)hydrogel composites with different hexagonal boron nitride(h-BN)fillers were synthesized and successfully 3D-printed while their thermal conductivity was systematically studied.With the content of h-BN increasing from 0.1 wt%to 0.3 wt%,the thermal conductivity of the 3D-printed composites has been improved.Moreover,through the shear force given by the 3D printer,a complete thermal conductivity path is obtained inside the hydrogel,which significantly improves the thermal conductivity of the h-BN hydrogel composites.The maximum thermal conductivity is 0.8808 W/(m·K),leading to a thermal conductive enhancement of 1000%,compared with the thermal conductivity of pure PAA hydrogels.This study shows that using h-BN fillers can effectively and significantly improve the thermal conductivity of hydrogelbased materials while its 3D-printable ability has been maintained.展开更多
Fibre reinforced polymer composites have become a new generation of structural materials due to their unique advantages such as high specific strength,designability,good dimensional stability and ease of large-area mo...Fibre reinforced polymer composites have become a new generation of structural materials due to their unique advantages such as high specific strength,designability,good dimensional stability and ease of large-area monolithic forming.However,the problem of interfacial bonding between the resin matrix and the fibres limits the direct use of reinforcing fibres and has become a central difficulty in the development of basalt fibre-epoxy composites.This paper proposes a solution for enhancing the strength of the fibre-resin interface using maize starch nanocrystals,which are highly yield and eco-friendly.Firstly,in this paper,corn starch nanocrystals(SNC)were prepared by hydrolysis,and were deposited on the surface of basalt fibers by electrostatic adsorption.After that,in order to maximize the modification effect of nano-starch crystals on the interface,the basalt fiber-epoxy resin composite samples were prepared by mixing in a pressureless molding method.The test results shown that the addition of basalt fibers alone led to a reduction in the strength of the sample.Deposition of 0.1 wt%SNC on the surface of basalt fibers can make the strength consistent with pure epoxy resin.When the adsorption amount of SNC reached 0.5 wt%,the tensile strength of the samples was 23.7%higher than that of pure epoxy resin.This is due to the formation of ether bond homopolymers between the SNC at the fibre-epoxy interface and the epoxy resin,which distorts the originally smooth interface,leading to increased stress concentration and the development of cracks.This enhances the binding of basalt fibers.The conclusions of this paper can provide an effective,simple,low-cost and non-polluting method of interfacial enhancement modification.展开更多
In this study,the effects of stacked nanosheets and the surrounding interphase zone on the resistance of the contact region between nanosheets and the tunneling conductivity of samples are evaluated with developed equ...In this study,the effects of stacked nanosheets and the surrounding interphase zone on the resistance of the contact region between nanosheets and the tunneling conductivity of samples are evaluated with developed equations superior to those previously reported.The contact resistance and nanocomposite conductivity are modeled by several influencing factors,including stack properties,interphase depth,tunneling size,and contact diameter.The developed model's accuracy is verified through numerous experimental measurements.To further validate the models and establish correlations between parameters,the effects of all the variables on contact resistance and nanocomposite conductivity are analyzed.Notably,the contact resistance is primarily dependent on the polymer tunnel resistivity,contact area,and tunneling size.The dimensions of the graphene nanosheets significantly influence the conductivity,which ranges from 0 S/m to90 S/m.An increased number of nanosheets in stacks and a larger gap between them enhance the nanocomposite's conductivity.Furthermore,the thicker interphase and smaller tunneling size can lead to higher sample conductivity due to their optimistic effects on the percolation threshold and network efficacy.展开更多
基金Funded by the National Natural Science Foundation of China(No.51678254)。
文摘Gypsum was used as substrate,and silica gel was mixed into substrate at a certain mass ratio to prepare humidity-controlling composites;moreover,the moisture absorption and desorption properties of gypsum-based composites were compared with adding different silica gel particle size and proportion.The morphological characteristics,the isothermal equilibrium moisture content curve,moisture absorption and desorption rate,moisture absorption and desorption stability,and humidity-conditioning performance were tested and analyzed.The experimental results show that,compared with pure-gypsum,the surface structure of the gypsum-based composites is relatively loose,the quantity,density and aperture of the pores in the structure increase.The absorption and desorption capacity increase along with the increase of silica gel particle size and silica gel proportion.When 3 mm silica gel particle size is added with a mass ratio of 40%,the maximum equilibrium moisture content of humidity-controlling composites is 0.161 g/g at 98% relative humidity(RH),3.22 times that of pure-gypsum.The moisture absorption and desorption rates are increased,the equilibrium moisture absorption and desorption rates are 2.68 times and 1.61 times that of pure-gypsum at 58.5% RH,respectively.The gypsum-based composites have a good stability,which has better timely response to dynamic humidity changes and can effectively regulate indoor humidity under natural conditions.
基金supported by the Basic Scientific Research Funds for Colleges and Universities affiliated to Hebei Province(JST2022005)Thanks are given to the financial support from the National Natural Science Foundation of China(22005099).
文摘MXenes are a family of two-dimensional(2D)layered transition metal carbides/nitrides that show promising potential for energy storage applications due to their high-specific surface areas,excellent electron conductivity,good hydrophilicity,and tunable terminations.Among various types of MXenes,Ti_(3)C_(2)T_(x) is the most widely studied for use in capacitive energy storage applications,especially in supercapacitors(SCs).However,the stacking and oxidation of MXene sheets inevitably lead to a significant loss of electrochemically active sites.To overcome such challenges,carbon materials are frequently incorporated into MXenes to enhance their electrochemical properties.This review introduces the common strategies used for synthesizing Ti_(3)C_(2)T_(x),followed by a comprehensive overview of recent developments in Ti_(3)C_(2)T_(x)/carbon composites as electrode materials for SCs.Ti_(3)C_(2)T_(x)/carbon composites are categorized based on the dimensions of carbons,including 0D carbon dots,1D carbon nanotubes and fibers,2D graphene,and 3D carbon materials(activated carbon,polymer-derived carbon,etc.).Finally,this review also provides a perspective on developing novel MXenes/carbon composites as electrodes for application in SCs.
文摘The shear behavior of backfill-rock composites is crucial for mine safety and the management of surface subsidence.For exposing the shear failure mechanism of backfill-rock composites,we conducted shear tests on backfill-rock composites under three constant normal loads,compared with the unfilled rock.To investigate the macro-and meso-failure characteristics of the samples in the shear tests,the cracking behavior of samples was recorded by a high-speed camera and acoustic emission monitoring.In parallel with the experimental test,the numerical models of backfill-rock composites and unfilled rock were established using the discrete element method to analyze the continuous-discontinuous shearing process.Based on the damage mechanics and statistics,a novel shear constitutive model was proposed to describe mechanical behavior.The results show that backfill-rock composites had a special bimodal phenomenon of shearing load-deformation curve,i.e.the first shearing peak corresponded to rock break and the second shearing peak induced by the broken of aeolian sand-cement/fly ash paste backfill.Moreover,the shearing characteristic curves of the backfill-rock composites could be roughly divided into four stages,i.e.the shear failure of the specimens experienced:stage I:stress concentration;stage II:crack propagation;stage III:crack coalescence;stage IV:shearing friction.The numerical simulation shows that the existence of aeolian sand-cement/fly ash paste backfill inevitably altered the coalescence type and failure mode of the specimens and had a strengthening effect on the shear strength of backfillrock composites.Based on damage mechanics and statistics,a shear constitutive model was proposed to describe the shear fracture characteristics of specimens,especially the bimodal phenomenon.Finally,the micro-and meso-mechanisms of shear failure were discussed by combining the micro-test and numerical results.The research can advance the better understanding of the shear behavior of backfill-rock composites and contribute to the safety of mining engineering.
基金the National Natural Science Foundation of China(No.51973080,92066104).
文摘Polymer dielectrics capable of operating efficiently at high electric fields and elevated temperatures are urgently demanded by next-generation electronics and electrical power systems.While inorganic fillers have been extensively utilized to improved high-temperature capacitive performance of dielectric polymers,the presence of thermodynamically incompatible organic and inorganic components may lead to concern about the long-term stability and also complicate film processing.Herein,zero-dimensional polymer dots with high electron affinity are introduced into photoactive allyl-containing poly(aryl ether sulfone)to form the all-organic polymer composites for hightemperature capacitive energy storage.Upon ultraviolet irradiation,the crosslinked polymer composites with polymer dots are efficient in suppressing electrical conduction at high electric fields and elevated temperatures,which significantly reduces the high-field energy loss of the composites at 200℃.Accordingly,the ultraviolet-irradiated composite film exhibits a discharged energy density of 4.2 J cm^(−3)at 200℃.Along with outstanding cyclic stability of capacitive performance at 200℃,this work provides a promising class of dielectric materials for robust high-performance all-organic dielectric nanocomposites.
基金the National Natural Science Foundation of China[grant numbers 52203038,52173036 and 52073107]the National Key Technology R&D Program of China[grant number 2022YFC3901904,2022YFC3901903,and 2020YFB1709301]the Central University Basic Research Fund of China[grant number 2021XXJS035].
文摘The severe dependence of traditional phase change materials(PCMs)on the temperature-response and lattice deficiencies in versatility cannot satisfy demand for using such materials in complex application scenarios.Here,we introduced metal ions to induce the self-assembly of MXene nanosheets and achieve their ordered arrangement by combining suction filtration and rapid freezing.Subsequently,a series of MXene/K^(+)/paraffin wax(PW)phase change composites(PCCs)were obtained via vacuum impregnation in molten PW.The prepared MXene-based PCCs showed versatile applications from macroscale technologies,successfully transforming solar,electric,and magnetic energy into thermal energy stored as latent heat in the PCCs.Moreover,due to the absence of binder in the MXene-based aerogel,MK3@PW exhibits a prime solar-thermal conversion efficiency(98.4%).Notably,MK3@PW can further convert the collected heat energy into electric energy through thermoelectric equipment and realize favorable solar-thermal-electric conversion(producing 206 mV of voltage with light radiation intensity of 200 mw cm^(−2)).An excellent Joule heat performance(reaching 105℃with an input voltage of 2.5 V)and responsive magnetic-thermal conversion behavior(a charging time of 11.8 s can achieve a thermal insulation effect of 285 s)for contactless thermotherapy were also demonstrated by the MK3@PW.Specifically,as a result of the ordered arrangement of MXene nanosheet self-assembly induced by potassium ions,MK3@PW PCC exhibits a higher electromagnetic shielding efficiency value(57.7 dB)than pure MXene aerogel/PW PCC(29.8 dB)with the same MXene mass.This work presents an opportunity for the multi-scene response and practical application of PCMs that satisfy demand of next-generation multifunctional PCCs.
基金The financial support by the National Natural Science Foundation of China(No.52002020)is acknowledged.
文摘Stemming from the unique in-plane honeycomb lattice structure and the sp^(2)hybridized carbon atoms bonded by exceptionally strong carbon–carbon bonds,graphene exhibits remarkable anisotropic electrical,mechanical,and thermal properties.To maximize the utilization of graphene’s in-plane properties,pre-constructed and aligned structures,such as oriented aerogels,films,and fibers,have been designed.The unique combination of aligned structure,high surface area,excellent electrical conductivity,mechanical stability,thermal conductivity,and porous nature of highly aligned graphene aerogels allows for tailored and enhanced performance in specific directions,enabling advancements in diverse fields.This review provides a comprehensive overview of recent advances in highly aligned graphene aerogels and their composites.It highlights the fabrication methods of aligned graphene aerogels and the optimization of alignment which can be estimated both qualitatively and quantitatively.The oriented scaffolds endow graphene aerogels and their composites with anisotropic properties,showing enhanced electrical,mechanical,and thermal properties along the alignment at the sacrifice of the perpendicular direction.This review showcases remarkable properties and applications of aligned graphene aerogels and their composites,such as their suitability for electronics,environmental applications,thermal management,and energy storage.Challenges and potential opportunities are proposed to offer new insights into prospects of this material.
基金Funded by the Hebei Province Natural Science Foundation (No.E2017203043)National Natural Science Foundation of China(No.U1604251)。
文摘A new,innovative vibration cast-rolling technology of “electromagnetic stirring+dendrite breaking+asynchronous rolling” was proposed with the adoption of sinusoidal vibration of crystallization roller to prepare Ti/Al laminated composites,and the effect of sinusoidal vibration of crystallization roller on composite microstructure was investigated in detail.The results show that the metallurgical bonding of titanium and aluminum is realized by mesh interweaving and mosaic meshing,instead of transition bonding by forming metal compound layer.The meshing depth between titanium and aluminum layers (6.6μm) of cast-rolling materials with strong vibration of crystallization roller (amplitude 0.87 mm,vibration frequency 25 Hz) is doubled compared with that of traditional cast-rolling materials (3.1μm),and the composite interfacial strength(27.0 N/mm) is twice as high as that of traditional cast-rolling materials (14.9 N/mm).This is because with the action of high-speed superposition of strong tension along the rolling direction,strong pressure along the width direction and rolling force,the composite linearity evolves from "straight line" with traditional casting-rolling to "curved line",and the depth and number of cracks in the interface increases greatly compared with those with traditional cast-rolling,which leads to the deep expansion of the meshing area between interfacial layers and promotes the stable enhancement of composite quality.
基金Natural Science Foundation of China,Grant/Award Numbers:51921005,52125703,52207029State Key Laboratory of Power System Operation and Control,Grant/Award Number:SKLD22KZ02。
文摘Recently,ZnO-based composites have been widely applied in the field of electric power.To meet the diverse application requirements,it is necessary to figure out the I-V characteristics of ZnO composites whose high-voltage and ground-voltage electrodes are arranged on the opposite sides with a certain horizontal distance.30 vol%,40 vol%and 50 vol%ZnO-based silicone rubber composites were prepared.The horizontal distance between their electrodes was set as 50,100,500μm,1 and 2 mm,respectively.Results showed that with the increase of ZnO fillers volume fraction under a fixed horizontal distance of 100μm,from 30 vol%to 50 vol%,the I-V curves shifted left,the leakage current increased and the switching voltage decreased.When the horizontal distance between electrodes increased from 50μm to 1 mm under a fixed doping concentration of 40%,the I-V curves shifted to the right,the leakage current dropped and the switching voltage rose.The mathematical and physical models were established to explain the results.This work provides a referential significance for the practical application of ZnO composites,such as 5G folding mobile phones and power electronic modules.
基金Science and Technology Project of SGCC,Grant/Award Number:SGTYHT/14-JS-188National Science Fund of Wuhu,Grant/Award Number:2022hg15“111”Project,Grant/Award Number:BP0820005。
文摘Surface flashover is a crucial issue for the miniaturisation of electronic facilities in military,industrial,and aerospace engineering.The oriented hexagonal boron nitride(hBN)composites,due to excellent thermal and electrical insulating properties,show a potential application in high-voltage power equipment,while the surface flashover performance of hBN composites dependent on oriented hBN texture is rarely reported.The effects of hBN orientation and contents on the surface flashover performances of oriented hBN composites are investigated.The isothermal surface potential decay of the oriented hBN composites was also studied.It is found that the charge transportation could be adjusted by the hBN orientation,thus regulating surface flashover strength.The DC flashover voltage of the in-plane oriented hBN composites with a thickness of 15μm reached the maximum of 27.6 kV at the hBN loading of 20 wt%,14.5%higher than that of the pure resin.The carrier mobility of out-of-plane oriented hBN composites is about three times greater than that of the in-plane oriented composites,indicating that the charges are easily transported along the hBN basal plane.The larger carrier mobility causes charge dissipation in composites near the electrode at the hBN basal plane parallel to the axis of electrodes and inhibits the distortion of the surface electric field on the composites,thus enhancing the surface flashover.Consequently,developing oriented insulators for highvoltage applications and enabling an optimum insulation design would be beneficial because of the compactness and high reliability of power apparatus for use in power grids.
基金Project supported by the National Key Research and Development Program of China(Grant No.2019YFA0704900)the National Natural Science Foundation of China(Grant No.52171221)。
文摘Materials with both large magnetocaloric response and high thermoelectric performance are of vital importance for all-solid-state thermoelectromagnetic cooling.These two properties,however,hardly coexist in single phase materials except previously reported hexagonal Cr_(1-x)Te half metal where a relatively high magnetic entropy change(-△S_(M))of~2.4 J·kg^(-1)·K^(-1)@5 T and a moderate thermoelectric figure of merit(ZT)of~1.2×10^(-2)@300 K are simultaneously recorded.Herein we aim to increase the thermoelectric performance of Cr_(1-x)Te by compositing with semiconducting Ag_(2)Te.It is discovered that the in-situ synthesis of Cr_(1-x)Te/Ag_(2)Te composites by reacting their constitute elements above melting temperatures is unsuccessful because of strong phase competition.Specifically,at elevated temperatures(T>800 K),Cr_(1-x)Te has a much lower deformation energy than Ag_(2)Te and tends to become more Cr-deficient by capturing Te from Ag_(2)Te.Therefore,Ag is insufficiently reacted and as a metal it deteriorates ZT.We then rationalize the synthesis of Cr_(1-x)Te/Ag_(2)Te composites by ex-situ mix of the pre-prepared Cr_(1-x)Te and Ag_(2)Te binary compounds followed by densification at a low sintering temperature of 573 K under a pressure of 3.5 GPa.We show that by compositing with 7 mol%Ag_(2)Te,the Seebeck coefficient of Cr_(1-x)Te is largely increased while the lattice thermal conductivity is considerably reduced,leading to 72%improvement of ZT.By comparison,-△S_(M)is only slightly reduced by 10%in the composite.Our work demonstrates the potential of Cr_(1-x)Te/Ag_(2)Te composites for thermoelectromagnetic cooling.
基金Funded by the State Grid Henan Electric Power Company Technology Project(No.521790200018)the 2021 Key Scientific Research Projects of Higher Education Institutions in Henan Province(No.21A430047)the Excellent Team Project of Scientific and Technological Innovation in Henan Province(HNST [2017] No.9)。
文摘In order to explore the thermal conductivity of polypropylene(PP)/hexagonal boron nitride(BN) composites,PP composites filled with different proportions of BN were prepared through extrution compounding,injection moulding and compression moulding.The composites were filled with BN particles of 5 and 20 μm respectively,and their mass fractions in composites were considered.Percentage of BN was varied from 0 to 25wt% in steps of 5wt%.The effects of BN filler on mechanical properties of the composites were evaluated.The thermal behaviors were studied using DSC and TGA,and the thermal conductivity was also investigated by Laser Flash Device and the Model of 3D Heat Conduction respectively.The experimental results show that impact strength of PP/BN can be enhanced with the addition of BN,but that composites exhibit lower breaking elongation & tensile strength when compared to unfilled ones.It is found that mass fraction of BN influenced the final thermal stability and degree of crystallization of PP matrix,the degree of crystallization of PP with 15wt% of 20 μm BN can be improved by 25% than neat PP.Meanwhile,crystallization temperatures of PP composites are elevated by about 10 ℃.The thermal conductivity results demonstrate that the maximum value of the thermal conductivity is achieved from PP/BN with 20wt% of 20 μm BN,higher than that of pure PP by 95.65%,close to the simulation one.
基金supported by the financial support from the National Key Research and Development Program of China(No.2022YFB3708400)National Natural Science Foundation of China(grant No.52305158)+1 种基金Science Innovation Foundation of Shanghai Academy of Spaceflight Technology(No.USCAST2021-18)Funding from Aero Engine 484 Cooporation of China(ZZCX-2022-020).
文摘Magnesium matrix composites have garnered significant attention in recent years owing to their exceptional lightweight properties and notable potential in various engineering applications.The interface generally acts as a“bridge”between the matrix and reinforcement,playing crucial roles in critical processes such as load transfer,failure behavior,and carrier transport.A deep understanding of the interfacial structures,properties,and effects holds paramount significance in the study of composites.This paper presents a comprehensive review of prior researches related to the interface of Mg matrix composites.Firstly,the different interfacial structures and interaction mechanisms encompassing mechanical,physical,and chemical bonding are introduced.Subsequently,the interfacial mechanical properties and their influence on the overall properties are discussed.Finally,the paper addresses diverse interface modification methods including matrix alloying and reinforcement surface treatment.
基金financially supported by the National Key Research&Development Program of China(Nos.2020YFB2008300,2020YFB2008303)。
文摘Titanium matrix composites reinforced with ceramic particles are considered a promising engineering material due to their combination of high specific strength,low density,and high modulus.In this study,the TA15-based composites reinforced with a volume fraction of 10% to 25%(TiB+TiC)were prepared using powder metallurgy and casting technique.Microstructural characterization and phase constitution were examined using optical microscopy(OM),scanning electron microscopy(SEM),and X-ray diffraction(XRD).In addition,the microhardness,room temperature(RT)and high temperature(HT)tensile properties of the composites were evaluated.Results revealed that the reinforcements are distributed uniformly even in the composites with a high volume of TiB and TiC.However,as the volume fraction exceeds 15%,TiB and TiC particles become coarsening and exhibit rod-like and dendritic-like morphology.Microhardness increases gradually from 321.2 HV for the base alloy to a maximum of 473.3 HV as the reinforcement increases to 25vol.%.Tensile test results indicate that a reinforcement volume fraction above 20% is beneficial for enhancing tensile strength and yield strength at high temperatures,but it has an adverse effect on room temperature elongation.Conversely,if the reinforcement volume fraction is below 20%,it can improve high-temperature elongation when the temperature exceeds 600℃.
基金funded under the ERANET Cofund Forest Value Program through Vinnova(Sweden)Valsts izglītības attīstības aģentūra(Latvia)+2 种基金Ministry of Education,Science and Sport(JIA)(Slovenia)Academy of Finland,The Research Council of Norway,and the National Science Centre,Poland(Agreement No.2021/03/Y/NZ9/00038)The Forest Value Program received funding from the Horizon 2020 Research and Innovation Program of the European Union under Grant Agreement No.773324.
文摘Bark extracts are sustainable sources of biopolymers and hold great promise for replacing fossil fuel-based polymers,for example,in wood-based composites.In addition to primary and secondary metabolites,tree bark also contains suberin,which plays a major role in protecting the tree from environmental conditions.Suberin is a natural aliphatic-aromatic cross-linked polyester present in the cell walls of both normal and damaged external tissues,the main component of which are long-chain aliphatic acids.Its main role as a plant ingredient is to protect against microbiological factors and water loss.One of the most important suberin monomers are suberin fatty acids,known for their hydrophobic and barrier properties.Therefore,due to the diverse chemical composition of suberin,it is an attractive alternative to hydrocarbon-based materials.Although its potential is recognized,it is not widely used in biocomposites technology,including wood-based composites and the polymer industry.The article will discuss the current knowledge about the potential of suberin and its components in biocomposites technology,which will include surface finishes,composite adhesives and polymer blends.
文摘Realising the potential of Magnesium(Mg),several globally leading ventures have invested in the Mg industry,but their relatively poor corrosion resistance is a never ending saga till date.The corrosion and bio-corrosion behaviour of Mg has gained research attention and still remains a hot topic in the application of automobile,aerospace and biomedical industries.The intrinsic high electrochemical nature of Mg limits their utilization in diverse application.This scenario has prompted the development of Mg composites with an aim to achieve superior corrosion and bio-corrosion resistance.The present review enlightens the influence of grain size(GS),secondary phase,texture,type of matrix and reinforcement on the corrosion and bio-corrosion behaviour of Mg composites.Firstly,the corrosion and bio-corrosion behaviour of Mg composites manufactured by primary and secondary processing routes are elucidated.Secondly,the comprehensive corrosion and bio-corrosion mechanisms of these Mg composites are proposed.Thirdly,the individual role of GS,texture and corrosive medium on corrosion and bio-corrosion behaviour of Mg composites are clarified and revealed.The challenges encountered,unanswered issues in this field are explained in detail and accordingly the scope for future research is framed.The review is presented from basic concrete background to advanced corrosion mechanisms with an aim of creating interest among the readers like students,researchers and industry experts from various research backgrounds.Indeed,the corrosion and bio-corrosion behaviour of Mg composites are critically reviewed for the first time to:(i)contribute to the body of knowledge,(ii)foster research and development,(iii)make breakthrough,and(iv)create life changing innovations in the field of Mg composite corrosion.
基金financially supported by the National Natural Science Foundation of China(Nos.52327802,52303101,52173078,and 52130303)the National Key R&D Program of China(No.2022YFB3805702)+2 种基金the China Postdoctoral Science Foundation(No.2023M732579)Young Elite Scientists Sponsorship Program by CAST(No.2022QNRC001)Joint Funds of Ministry of Education(No.8091B032218).
文摘With the rapid development of science and technology,electronic devices are moving towards miniaturization and integration,which brings high heat dissipation requirements.During the heat dissipation process of a heating element,heat may spread to adjacent components,causing a decrease in the performance of the element.To avoid this situation,the ability to directionally transfer heat energy is urgently needed.Therefore,thermal interface materials(TIMs)with directional high thermal conductivity are more critical in thermal management system of electronic devices.For decades,many efforts have been devoted to the design and fabrication of TIMs with high-directional thermal conductivity.Benefiting from the advantage in feasibility,low-cost and scalability,compositing with thermal conductive fillers has been proved to be promising strategy for fabricating the high-directional thermal conductive TIMs.This review summarizes the present preparation technologies of polymer composites with high-directional thermal conductivity based on structural engineering of thermal conductive fillers,focusing on the manufacturing process,mechanisms,achievements,advantages and disadvantages of different technologies.Finally,we summarize the existing problems and potential challenges in the field of directional high thermal conductivity composites.
基金the National Natural Science Foun-dation of China(Grant Nos.91963201 and 12174163)the 111 Project(Grant No.B20063).
文摘The lack of soft magnetic composites with high power density in MHz frequency range has become an obstacle in the efficient operation of the electrical and electronic equipments.Here,a promising method to increase the cut-off frequency of iron-based soft magnetic composites to hundreds of MHz is reported.The cut-off frequency is increased from 10 MHz to 1 GHz by modulating the height of the ring,the distribution of particles,and the particle size.The mechanism of cut-off frequency and permeability is the coherent rotation of domain modulated by inhomogeneous field due to the eddy current effect.An empirical formula for the cut-off frequency in a magnetic ring composed of iron-based particles is established from experimental data.This work provides an effective approach to fabricate soft magnetic composites with a cut-off frequency in hundreds of MHz.
基金Funed by the National Key Research and Development Program of China(No.2021YFA0715700)the Open Fund of Hubei Longzhong Laboratory。
文摘Polyacrylic acid(PAA)hydrogel composites with different hexagonal boron nitride(h-BN)fillers were synthesized and successfully 3D-printed while their thermal conductivity was systematically studied.With the content of h-BN increasing from 0.1 wt%to 0.3 wt%,the thermal conductivity of the 3D-printed composites has been improved.Moreover,through the shear force given by the 3D printer,a complete thermal conductivity path is obtained inside the hydrogel,which significantly improves the thermal conductivity of the h-BN hydrogel composites.The maximum thermal conductivity is 0.8808 W/(m·K),leading to a thermal conductive enhancement of 1000%,compared with the thermal conductivity of pure PAA hydrogels.This study shows that using h-BN fillers can effectively and significantly improve the thermal conductivity of hydrogelbased materials while its 3D-printable ability has been maintained.
基金Supported by National Key Research and Development Project of China (Grant Nos.2018YFA0703300,52105300)National Natural Science Foundation of China (Grant No.52075215)+2 种基金Science and Technology Development Plan Project of Jilin Province of China (Grant No.20200201061JC)Science and Technology Research Project of Jilin Provincial Education Department of China (Grant No.JJKH20221021KJ)Changchun Municipal Key Research and Development Program of China (Grant No.21ZGN22)。
文摘Fibre reinforced polymer composites have become a new generation of structural materials due to their unique advantages such as high specific strength,designability,good dimensional stability and ease of large-area monolithic forming.However,the problem of interfacial bonding between the resin matrix and the fibres limits the direct use of reinforcing fibres and has become a central difficulty in the development of basalt fibre-epoxy composites.This paper proposes a solution for enhancing the strength of the fibre-resin interface using maize starch nanocrystals,which are highly yield and eco-friendly.Firstly,in this paper,corn starch nanocrystals(SNC)were prepared by hydrolysis,and were deposited on the surface of basalt fibers by electrostatic adsorption.After that,in order to maximize the modification effect of nano-starch crystals on the interface,the basalt fiber-epoxy resin composite samples were prepared by mixing in a pressureless molding method.The test results shown that the addition of basalt fibers alone led to a reduction in the strength of the sample.Deposition of 0.1 wt%SNC on the surface of basalt fibers can make the strength consistent with pure epoxy resin.When the adsorption amount of SNC reached 0.5 wt%,the tensile strength of the samples was 23.7%higher than that of pure epoxy resin.This is due to the formation of ether bond homopolymers between the SNC at the fibre-epoxy interface and the epoxy resin,which distorts the originally smooth interface,leading to increased stress concentration and the development of cracks.This enhances the binding of basalt fibers.The conclusions of this paper can provide an effective,simple,low-cost and non-polluting method of interfacial enhancement modification.
基金the Basic Science Research Program through the National Research Foundation(NRF)of Korea funded by the Ministry of Education,Science,and Technology(No.2022R1A2C1004437)the Ministry of Science and ICT(MSIT)of Korea Government(No.2022M3J7A1062940)。
文摘In this study,the effects of stacked nanosheets and the surrounding interphase zone on the resistance of the contact region between nanosheets and the tunneling conductivity of samples are evaluated with developed equations superior to those previously reported.The contact resistance and nanocomposite conductivity are modeled by several influencing factors,including stack properties,interphase depth,tunneling size,and contact diameter.The developed model's accuracy is verified through numerous experimental measurements.To further validate the models and establish correlations between parameters,the effects of all the variables on contact resistance and nanocomposite conductivity are analyzed.Notably,the contact resistance is primarily dependent on the polymer tunnel resistivity,contact area,and tunneling size.The dimensions of the graphene nanosheets significantly influence the conductivity,which ranges from 0 S/m to90 S/m.An increased number of nanosheets in stacks and a larger gap between them enhance the nanocomposite's conductivity.Furthermore,the thicker interphase and smaller tunneling size can lead to higher sample conductivity due to their optimistic effects on the percolation threshold and network efficacy.