Hydrogels are polymeric materials with unique three-dimensional network structures.Their high water content and biocompatibility make them widely applicable in many fields.The basic concepts,classification,and preparation methods of hydrogels were systematically discussed.The applications in different fields were deeply analyzed.Subsequently,a comprehensive summary was conducted on the applications of hydrogels in biomedical engineering,industry,agriculture,and daily life.Finally,the main challenges faced by hydrogels were summarized and the future development directions were envisioned.

Nickel rich ternary cathode material (Li(Ni_1-x-yCo_xMn_y)O₂,x+y≤0.4,denoted as NCM) still faces some issues such as poor structure stability and serious interface side reactions at high-voltage,which limits the application in power lithium-ion batteries.The structure stability and electrochemical performance of nickel rich ternary cathode materials can be significantly improved by various modification techniques,such as ion doping,surface coating,electrolyte optimization and composite modification.This review summarized the modification and optimization methods for enhancing the high-voltage performance of nickel rich ternary cathode materials.It was found that doping elements could inhibit the adverse phase transition and enhance the diffusion of lithium ions.Surface coating could effectively isolate the electrode from the electrolyte and reduce side reactions.Electrolyte optimization could form a stable interface layer and improve cycle performance and capacity retention.In particular,synergistic modification could further prominently improve the overall performance of nickel rich ternary cathode materials at high-voltage.The research on the high-voltage performance of nickel rich ternary cathode materials could provide new theoretical support and basis for their application in high-energy-density power lithium-ion batteries.

In the context of the increasingly depleting fossil fuels and increasingly severe environmental problems,environmental and energy issues have become important focus areas for the future development of human society,and energy storage has emerged as a strategic issue.Aqueous zinc-ion batteries(ZIBs) have the advantages of high specific capacity,low cost,high safety and environmental friendliness,but there are some problems such as dendrite growth,corrosion and passivation,hydrogen evolution reaction,thus limiting the practical application and large-scale commercial development of ZIBs.The development history and energy storage mechanism of ZIBs were briefly introduced,the existing problems and reasons of zinc anodes were summarized,the modification methods of zinc anodes were reviewed,and the future research direction was prospected.

As an important industrial fiber,the properties of nylon 66 industrial filament are affected by a number of factors during the production process.The article firstly gave an overview of the characteristics and application scope of nylon 66 fiber,then introduced the molecular structure features,condensed state structure features and properties of nylon 66,and then expounded on the production process and apparatus of nylon 66 industrial filament,including the two processes of continuous polycondensation direct spinning and batch polycondensation solid-state polycondensation spinning.The article emphasized on the key factors affecting the production of nylon 66 industrial filament and action rules,including the molecular weight of nylon 66 polymer,chip moisture content and extractable content,spinning box temperature,spinning component filter material and filter screen,side blowing air cooling process,wetting,oiling process,spinning speed,winding process,drawing process,network degree,spinning environmental conditions,etc.,and provided the optimal range of process parameters.Finally,the article summarized the development prospects and market potential of nylon 66 fiber in China.

This article systematically reviewed the research progress of Al/PTFE composite materials.In terms of the dynamic mechanical properties of composite materials,the larger the strain rate,the higher the material strength.The increase in Al content in composite materials results in an increase in elastic modulus and yield strength.As the temperature increases,the toughness of the composite material increases,but the dynamic compressive strength decreases.Iron powder,nickel powder,tungsten powder,copper oxide,titanium hydride,zirconium hydride,etc.can improve the compressive strength of Al/PTFE composites.Regarding the thermal performance of composite materials,the heat release of Al/n-PTFE is much higher than that of other aluminothermic agents,and the reactivity between nanoscale aluminum powder and PTFE is better than that of microscale aluminum powder.For ignition and combustion performance of composite materials,when the mass content of PTFE in the composite material is about 35%,the composite material exhibits the highest combustion pressure,the shortest combustion time,and the highest center flame temperature.Composite material samples with confined hollow structures burn better than samples with solid,hollow,and core-shell structures.Titanium hydride,ammonium perchlorate,and carbon nanotubes have a certain combustion supporting effect.As far as the impact response performance of composite materials,the higher the loading strain rate,the smaller the reaction delay time of the material,and the more intense the reaction.Moreover,the reactivity and degree of reaction of nanoscale aluminum powder are better than those of micrometer scale aluminum powder.Adding oxides (bismuth trioxide,copper oxide,molybdenum trioxide,and iron trioxide) can adjust the energy release characteristics of materials.In light of the reaction completeness of composite materials,the higher the launching rate of materials as projectiles,the more complete the reaction.The aluminum content has a very significant effect on the completeness of the reaction.Copper oxide can improve the completeness of the reaction.As for the application scenarios of composite materials,the damage effect of materials on target plates,arson ability,improvement of propellant mechanical properties and combustion efficiency,and the protective effect as protective materials have significantly improved compared to traditional materials.The research results of this article are expected to be an important reference for practitioners in the explosive and warhead industries.

Supercapacitors have received widespread attention in the energy storage industry due to their smaller volume,faster charge-discharge process and longer cycle life than traditional capacitors.Supercapacitor is an advanced energy storage device,which uses the double-layer charge distribution between the electrode and the electrolyte to store energy.It has the advantages of pollution-free and sustainable development.Among them,the most familiar graphene materials are the most widely used and play an important role.This paper summarized the history and manufacturing technology of graphene,and reviewed and prospected the application of graphene and other materials in supercapacitors in recent years.

MXene is an emerging class of inorganic two-dimensional (2D) structural materials following graphene,which has attracted wide attention in the fields of materials science,biomedicine and nanotechnology in recent years.MXene has good thermal stability,unique layered structure,excellent catalytic activity and adjustable chemical properties,which will confer excellent flame-retardant properties to the materials if it is used as a flame retardant for flame-retardant treatment.This paper described in detail the preparation methods of MXene by etching and chemical vapor deposition,as well as the flame-retardant mechanism of MXene and the research progress of MXene flame-retardant materials.It highlighted the advancements in modifying MXene flame-retardant materials through the addition of modifiers,surface functional group modifications and covalent bonding functionalization,and the research on the synergistic enhancement of polymer flame-retardant effect by MXene with other flame retardants to improve the flame retardancy of polymers.Finally,the development prospect of MXene flame-retardant materials was also prospected.

With the rise of the new energy industry represented by lithium-ion batteries,the demand for lithium has increased dramatically,so the technology of lithium extraction from salt lake brine has received widespread attention.The lithium extraction technology from salt lake brine using lithium ion sieves as adsorbents is environmentally friendly,efficient and sustainable.This paper introduced the types of lithium extraction technology from salt lake brine,reviewed the synthesis methods of titanium-based lithium-ion sieves and the research progress of titanium-based lithium-ion sieve nanomaterials,and compared the advantages and disadvantages of different titanium-based lithium-ion sieve synthesis methods.Finally,it looked forward to the research direction of titanium-based lithium-ion sieves.

Conventional rigid sensors are severely limited in their applications due to problems such as difficulty in integrating them into flexible electronics and inability to adapt to complex deformation environments.The preparation of flexible sensors based on human perception is one of the effective solutions to these problems.The working mechanisms of piezoresistive,capacitive and piezoelectric flexible pressure sensors were summarized.It focused on the current research status of ionic flexible pressure sensors from the perspective of the ionic active materials used in the sensing layer and microstructural design.Furthermore,it reviewed the applications of ionic flexible pressure sensors in the fields of electronic skin,healthcare and motion detection.

Metal-organic frameworks (MOFs) have been widely used in optical sensing,and quantum dots (QDs) also have excellent optical properties,which can be introduced into MOFs to enhance their optical activity.Because MOFs have a larger pore size to accommodate QDs,they can effectively avoid the reduction of optical activity caused by QD aggregation.QD@MOF composite materials combine the advantages of excellent optical properties and specific recognition of QDs and MOFs,enhancing the sensitivity and selectivity of composite materials in the field of fluorescence sensors.This paper reviewed three common methods for synthesizing QD@MOF composite materials:ship in bottle method,ship-around-bottle method,and physical mixing method.It also summarized the application of QD@MOF materials for fluorescent sensors in detecting substances such as metal ions,biomolecules,gases,nitro compounds and other substances.Finally,it briefly discussed the current problems and future development directions.

Silicone materials are widely used in the field of electronics because of their excellent flexibility,chemical resistance,insulation,low viscosity and temperature resistance,but their lower thermal conductivity hinder their own application and development.Therefore,the development of high heat-conducting organic silicon materials is a challenge.This article introduced the thermal conductivity mechanism of organic silicon composite material,types of heat conduction filler,focusing on the methods and means to improve the thermal conductivity of thermal conductivity composite materials at home and abroad,summarized and looked forward to the dilemma and research key directions of high thermal conductivity organic silicon materials,offering insights and references for the further research of high thermal conductivity organic silicon materials.

The shortage of freshwater resources has become a prominent problem faced by mankind,but the traditional water treatment technology has the problems of high cost,high energy consumption and low efficiency.Due to the green and sustainable characteristics of solar energy,the application of interfacial solar evaporators composed of aerogel materials for seawater desalination,sewage and wastewater treatment has attracted great attention.In the process of interfacial solar photothermal evaporation for water treatment,the efficiency of water treatment is closely related to the absorption and utilization of solar energy,water transport channel and heat management,especially the absorption and utilization of solar energy.This paper briefly summarized the application and research progress of organic aerogel materials in interfacial solar photothermal evaporation technology,including the types of photothermal materials used in organic aerogel materials and the introduction of the conversion mechanism of the photothermal conversion materials,and focusing on the research and applications of organic aerogel materials loaded with different photothermal materials in interfacial solar photothermal evaporation for water treatment.The development trend of organic aerogel materials in interfacial solar photothermal evaporation for water treatment was also prospected.

In nature,many organisms show strong antifreeze capacity and can survive in extremely cold environments.Inspired by these biological antifreeze properties,researchers have developed a number of advanced antifreeze hydrogel materials and explored their potential applications in diverse fields such as flexible electronics,flexible energy,and bioscience.Based on the basic mechanism of antifreeze of cold-resistant organisms,two kinds of strategies for synthesis of antifreeze hydrogels to inhibit the formation of ice nuclei and the growth of ice crystals were summarized:one was to introduce organic solvents,acids,zwitterion,salts and other methods to inhibit the formation of ice nucleation;the other was to introduce antifreeze proteins (AFP),construct core-shell nanostructures,and polymer interpenetrating network structures (IPNs) to inhibit ice crystal growth.The advantages and disadvantages of each strategy were briefly introduced,and the relationship between the synthetic strategy and the properties of the obtained hydrogels was discussed.Finally,the future development direction of antifreeze hydrogels was proposed.

The polyimide (PI) nanofiber membranes prepared by electrospinning method exhibit higher porosity,permeability,and surface area,thereby integrating and amplifying the excellent properties of polyimide materials and micro-nano structures.In our work,starting from the two concepts and characteristics of PI and electrostatic spinning,this polymer material with special micro-nano structure and micro-morphology was introduced.The existing process strategies for preparing PI nanofiber membranes were summarized,focusing on the related modification techniques of polyimide fiber membranes and elucidating their specific performance advantages.Furthermore,the future development trends and key technical challenges faced by polyimide nanofiber membranes were pointed out.

Anode-free lithium metal batteries are expected to become the next generation of energy storage devices due to their ultra-high energy density,excellent safety,and good economy.However,a series of problems such as high interface contact resistance,lithium dendrites,and dead lithium formation lead to a shortened cycle life.In recent years,researchers have conducted some research works on optimizing electrolytes and deposition substrates to extend battery life.This article elaborated on the current development status and existing problems of anode-free lithium metal batteries,focusing on the research progress of electrolyte optimization,SEI interface modification,current collector modification and other strategies to improve the cycling stability of batteries.Finally,the future opportunities and possible development directions of anode-free lithium metal batteries were analyzed and discussed.

New chemical materials refer to materials characterized by novel structures,innovative preparation methods,improved performance metrics,and expanded application domains,developed through chemical research,synthesis,and utilization.As a cornerstone of the national economy,new chemical materials constitute a critical foundation for technological progress.In recent years,China's new chemical materials industry has undergone rapid advancement,particularly in areas such as energy storage materials,photoelectric conversion materials,photocatalytic materials,electronic materials,high-performance resins and fiber materials for advanced composites,as well as functional coatings and adhesives.These materials have played a pivotal role in driving development across multiple sectors,including wind power,photovoltaics,new energy vehicles,aerospace,and semiconductor packaging and testing,thereby fostering the emergence of high-quality productivity.To systematically document and disseminate these advancements,the New Chemical Materials Professional Committee of the CIESC will organize leading experts and scholars to compile an annual report on scientific and technological progress of new chemical materials of the year.This report will be published in the journal New Chemical Materials,providing a comprehensive resource for researchers and practitioners.

Nanocellulose,a new type of biobased naturally functional nanomaterials,has a broad range of application prospects in composite materials,packaging,pharmaceutical materials,coatings,cosmetics,electronic materials,and so on.However,nanocellulose still faces some major challenges in its preparation process,such as high energy and water consumption,thereby leading to high production cost.Additionally,traditional nanocellulose preparation methods are usually carried out under lower cellulose concentration conditions (less than 5%),which results in low production efficiency per unit volume and high content of water in the final products.This poses significant difficulties and challenges for transportation,storage,and applications,limiting its market promotion and practical application.Therefore,the development of high-consistency preparation techniques of nanocellulose has attracted growing attention,as it may help address issues such as high energy/water consumption,potentially further reducing production and application cost.

In order to prepare water-soluble and high-temperature resistant epoxy resin,improve its storage stability and safety,and reduce environmental pollution,epoxy resin E20 and E44 were used as raw materials,and the mixed epoxy resin was modified by in-situ blending phosphorylation synthesis process to prepare the high-temperature resistant phosphorylation-modified water-soluble epoxy resin.Its synthesis process was optimized and the optimal process parameters were determined.The structure and properties of phosphorylated-modified water-soluble epoxy resin were characterized by Fourier transform infrared spectrometer,nuclear magnetic resonance spectrometer and thermogravimetric analyzer.The optimum process conditions were as follows:m(E20)∶m(E44)=5∶5,the molar ratio of epoxy value to phosphoric acid was 1∶1.2,the reaction temperature was 50℃,the reaction time was 150min,m(H₂O)∶m(H₃PO₄)=2.3∶1.The prepared phosphorylated modified water-soluble epoxy resin had a small particle size,and the average particle size of the modified epoxy resin emulsion with a mass fraction of 1% was 11.8nm,and it was stable without delamination after centrifugation at a speed of 4000r/min for 30min.It had excellent high-temperature resistance,with an initial decomposition temperature of 297.4℃,a mass residue rate of 72.20% at 400℃,and a mass residue of up to 36.68% at 600℃.The critical micelle concentration of the modified resin was 0.5%,and the surface tension was 38.86mN/m,showing good surface activity.The viscosity-temperature characteristics of the modified water-soluble epoxy resin emulsion was good,and the viscosity sensitivity was small.

In the face of escalating antibiotic resistance due to widespread usage,the persistent emergence of multidrug-resistant pathogens is a formidable threat to human health.Traditional low-molecular-weight antibacterial agents,when used alone,often fall short of achieving desired efficacy,hampered by issues of biocompatibility and stability.The introduction of polymeric antibacterial materials,characterized by diverse synthesis strategies and higher efficiency,offers a promising approach to combatting pathogenic microorganisms.Contrasted with their low-molecular-weight organic or inorganic antibacterial materials,these materials demonstrate commendable biocompatibility,controllable functional attributes,and a more extensive range of structural designs,enabling inhibitory and bactericidal effects through diverse mechanisms.Their widespread adoption is observed in treating drug-resistant bacterial infections,formulating advanced wound dressings,targeted antibacterial interventions,and developing antibacterial coatings.This discourse provided a comprehensive classification and summary of existing polymeric antibacterial materials,considering synthesis strategies and mechanisms of action.It also outlined current challenges in their development and offered a forward-looking perspective on future directions,with the overarching goal of leveraging the intrinsic strengths of polymeric antibacterial materials for broader application.

Currently,traditional gas separation methods such as cryogenic distillation suffer from low efficiency,high cost and safety hazards.Recently,MOF membranes with unique properties have gradually become a research hotspot.ZIF-67 is an ultra-microporous sized MOF material,which is ideal for carbon dioxide capture due to its well-defined pore size,especially its small size of 3.4Å,which makes it highly efficient in gas adsorption and separation,and suitable for separation according to the size of molecules.Moreover,ZIF-67 has excellent thermal stability,which is crucial in practical applications.In this study,we investigated the growth of ZIF-67 membranes with high separation performance from ZIF-67 nanosheet crystal species by a conventional secondary growth method using α-Al₂O₃ carrier tubes.By optimizing the synthesis conditions,excellent CO₂ separation performance was achieved,with an ideal H₂/CO₂ selectivity of 26.99 and an H₂ flux of 2.41×10^-8mol/(s·Pa·m²).

The “layer by layer” Janus-PAN nanofiber membrane was prepared by continuous electrospinning.The Janus-PAN nanofiber membrane was composed of hydrophilic polyacrylonitrile (PAN) nanofiber membrane as the bottom layer,polyacrylonitrile/polyurethane (PAN/PU) blended nanofiber membrane as the middle layer,and hydrophobically modified SiO₂ nanoparticles as the top layer.The surface morphology,chemical composition,surface wettability and mechanical properties of Janus-PAN nanofiber membranes were analyzed and tested by field emission scanning electron microscope,Fourier transform infrared spectrometer,contact angle measuring instrument and electronic single fiber strength instrument.The oil-water separation and recycling properties of the Janus-PAN nanofiber membrane were investigated.The results showed that Janus-PAN nanofiber membrane had asymmetric wettability and could effectively switch between water-in-oil emulsion and oil-in-water emulsion,and still had high separation efficiency after 8 cycles of separation experiments.In addition,the separation efficiency of petroleum ether in water and engine oil in water emulsion could exceed 99.2% and 99.0%,respectively.The separation efficiency of water in peanut oil and water in paraffin oil emulsion could reach over 97.3% and 98.6%.

The preparation of composite materials by efficient extraction,treatment and use of natural biomass materials is one of the key research contents in the field of material research and development.Camellia oleifera shell is an accessory product of camellia oleifera fruit,which has a large amount of output every year with the harvest of camellia oleifera fruit,and has potential value as a raw material of biomass composite materials.In this paper,camellia oleifera shell materials were introduced,and the relevant research and application status of camellia oleifera shell in cellulose extraction,direct preparation of wood-plastic composite materials and preparation of biomass carbon composite materials were described in detail,aiming to provide certain guidance for the high-value utilization of abundant camellia oleifera shell materials.

In order to prepare high molecular weight polyacrylonitrile (PAN),a homogeneous solution polymerization was carried out using organic solvent dimethyl sulfoxide (DMSO) as the reaction medium,and acrylonitrile (AN) and itaconic acid (IA) as the reaction monomers.By changing the initiator type,comonomer ratio,initiator concentration,reaction temperature and reaction time,the PAN copolymer with higher molecular weight and high conversion rate was prepared.It was found that the viscous molecular weight of the PAN polymer obtained by using ammonium persulfate (APS) as the initiator was higher than the other two initiators,azo diisobutylamidine hydrochloride (V50) and azo diisobutyronitrile (AIBN).The overall polymerization reaction conversion showed a downward trend because of the introduction of the second comonomer IA.While the molecular weight presented a trend of increasing first and then decreasing,and reached the maximum value at 2wt% of IA in the feed.When the amount of comonomer IA was 1wt%～2wt%,PAN copolymers with higher conversion rate and molecular weight could be obtained.From the infrared spectra spectrum,it could be seen that the absorption peak near 2240cm^-1 represented the stretching vibration absorption peak of the C≡N was the strongest,which indicated that the AN unit existed in the copolymer as a long chain continuity.

Epoxy resin is a polymer material known for its high strength and rigidity,good chemical stability,and ease of processing.However,its brittleness seriously limits its applications.To address the toughening of epoxy resin,domestic and foreign scholars have conducted extensive research.The article mainly introduced the research progress on the modification of epoxy resins using toughening agents in recent years,involving toughening materials such as rubber elastomers,thermoplastic polymers,nanomaterials,flexible segments,hyperbranched polymers,and block copolymers.Additionally,future directions for the development of toughening technologies for epoxy resin were discussed,aiming to provide theoretical guidance for future research.It is anticipated that future researchers can advance the development of epoxy resin toughening design by exploring methods of filling,modification,toughening mechanisms and operability.

Ceramizable phenolic resin composite is a new type of heat-resistant material composed of phenolic resin matrix,ceramic-forming fillers,fluxing agents,and other additives.This kind of material can form a ceramic layer at high temperature,which plays a role in blocking oxygen and heat,and improving the heat resistance of the material.The article reviewed the main fillers and heat resistance modification of ceramizable phenolic resin composites,and discussed the future prospects of ceramizable phenolic resin composites.

With the rapid development of communication technology in civil and military fields,the waste electromagnetic radiation pollution caused by electromagnetic wave has become particularly prominent.In order to solve the negative impact of electromagnetic pollution on the human living environment,it is urgent to find a new kind of absorbing material that is lightweight,has high absorption performance,and possesses a wide absorption frequency band.Traditional single absorbing materials have narrow absorption frequency band and weak absorption performance.However,good impedance matching can be achieved by combining magnetic loss material with dielectric loss material.The basic principle of electromagnetic absorption was described,and the research progress and development prospect of several common new composite absorbing materials at home and abroad were introduced.The synthesis methods,structures,advantages and disadvantages and properties of new materials such as conductive polymer composite absorbing materials,biomass-derived carbon-based composite absorbing materials and magnetic metal composite absorbing materials were summarized,providing a reference for the development of high efficiency wideband absorbing materials with strong absorption performance,wide absorption frequency band,thin thickness and lightweight.

The recycling of spent LiFePO₄ batteries is a topic that researchers have paid extensive attention to.Compared with the hydrometallurgy and pyrometallurgy technologies for the purpose of extracting valuable metals,the repair and regeneration technology has the advantages of low energy consumption,short process and more environmentally friendly.Due to its stable olivine crystal structure and low content of high-value metals,the repair and regeneration of spent LiFePO₄ battery cathode materials is an economic option.The latest research status of three pretreatment methods represented by physical method,thermal treatment method and chemical method was reviewed.The technological progress in the repair and regeneration methods of cathode materials of spent LiFePO₄ was summarized,including high temperature solid-phase regeneration,hydrothermal synthesis method and electrochemical method.The existing problems in the repair and regeneration technology of spent LiFePO₄ battery cathode materials were analyzed,and suggestions were put forward.

SBS-based flexible strain sensors have come into the public's view in recent decades because of their excellent mechanical properties and good sensing performance.The signal sensing mechanism of strain sensors was introduced,the preparation process of SBS-based flexible strain sensors and the sensing mechanism of different carbon nanomaterials were summarized,and the application of composites composed of SBS-based matrix and different carbon nanomaterials was envisioned.

Due to its benefits like low cost,easy availability,environmental friendliness,and good catalytic activity,graphite carbon nitride (g-C₃N₄) has steadily emerged as a research hotspot in the fields of catalysis and environment.However,pure g-C₃N₄ has the disadvantage of low absorption efficiency for visible light.The solution to this problem is to modify the skeletal structure of g-C₃N₄ by element doping.Specifically focusing on binary and multi-component combinations of elements containing oxygen,phosphorus,boron,and halogen,the research on the combination doping of non-metallic elements over the past few years was systematically summarized in this paper.Additionally,problems in the work on non-metallic element doping were identified,and the prospects for future development were discussed.

In lithium-ion batteries,the cathode material is one of critical factors determining the battery's energy density and cycle life.As a component that bonds the cathode material,conductive material,and current collector,the binder plays a crucial role in the structural stability and electrochemical performance of the electrode.Polyvinylidene fluoride (PVDF) is a significant binder utilized in lithium-ion batteries.During the charge and discharge processes,the phenomena of lithium deintercalation and intercalation within the electrode subject the structure to mechanical stress,resulting in volume changes of the PVDF binder.This not only contributes to the degradation of battery capacity but also results in suboptimal performance under high-rate conditions due to its relatively low ionic conductivity.This paper summarized the latest research findings on PVDF binders in lithium-ion batteries.It delved into an in-depth analysis of the impact of modified PVDF on the electrochemical properties of lithium batteries and the mechanism by which the electrolyte/active material interface was formed.The paper systematically elucidated the effects of PVDF modification strategies on enhancing the performance of lithium-ion batteries and offered a perspective on the future development of high-performance PVDF binders.

Fiber-reinforced polymer-based composites have been widely used in many industries for their excellent mechanical properties.However,it is difficult to analyze the integrity and durability of fiber-reinforced polymer-based composites due to their own structural characteristics as well as the complexity of the environment and loading conditions they are subjected to.The use of structural health monitoring (SHM) techniques to monitor the structural condition of composites improves the safety and reliability of composite structures and has been widely used in many industries.This paper reviewed the SHM methods and their applications for fiber-reinforced polymer-based composites based on electrical resistance sensing,and gave an outlook on the development of SHM for fiber-reinforced polymer-based composites.

Graphene (G) and carbon black (CB) were used to jointly construct micro/nano rough structures on the surface of transmission lines,while non-fluorinated n-octyltriethoxysilane (OTES) was introduced as a low-surface-energy substance to endow the surface of the carbon particles with hydrophobic groups,and G/CB@OTES superhydrophobic anti-icing coatings were prepared on the surfaces of the transmission lines by the spray-brush combination method.By studying the effect of different concentrations of G/CB on the micromorphology and wettability of the coatings,the optimal doping concentration was determined.The morphology and chemical bonding of the coatings on transmission lines were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR).Contact angle testing,photothermal performance testing,anti-icing testing,de-icing testing,and mechanical durability testing were conducted to comprehensively evaluate the anti-icing and de-icing performance of the photothermal superhydrophobic coatings.The research results showed that the contact angle of the photothermal superhydrophobic coatings on transmission lines was as high as 158.3°±3.6°,and the sliding angle was as low as 4.6°±1.5°,which could extend the freezing time to 61 minutes.In addition,under simulated sunlight exposure,the surface temperature of the coatings on the transmission lines rapidly increased to 98.5℃ within 10 minutes,and was able to melt the frozen droplets within 151s.The above results confirmed that the application of photothermal superhydrophobic coatings on the surface of transmission lines could achieve efficient anti-icing/de-icing and provide an important reference for their application in the field of anti-icing in transmission engineering.

This paper reviewed the latest research progress in the application of polydimethylsiloxane (PDMS) composite foams.The preparation methods,including PDMS foam template method,liquid emulsion method,gas phase foaming method,solvent evaporation-induced phase separation method and 3D printing method,were introduced in detail.In recent years,the preparation of composite foams by adding various types of fillers to PDMS foams has become a hot research topic.The commonly used fillers for composite foams include carbon materials,metal nanomaterials,conductive polymers,transition metal carbides,and so on.In addition,the relevant application achievements of PDMS composite foams in the fields of piezoresistive sensing,electromagnetic shielding,oil-water separation,acoustic absorption and flame retardancy were introduced in detail.

Gel electrolyte with high ionic conductivity and excellent comprehensive performance is a research hotspot in the field of energy storage materials.A hydrogel polymer electrolyte based on polyvinyl alcohol (PVA) and chitosan (CS) was prepared by a simple freeze-thaw method,and high ionic conductivity was obtained.The effects of hydrogel freezing time,soaking time in the electrolyte,and the types of electrolytes on the ionic conductivity of the hydrogel were systematically explored.The suitable preparation conditions for the physical crosslinking PVA/CS gel electrolyte were obtained.The results showed that the PVA/CS gel had a relatively uniform three-dimensional-hole structure and low crystallinity when the mass ratio of PVA to CS was 1∶2,and the hydrogel was frozen for 5h and thawed for 12h.No infinite swelling and dissolution of the hydrogel occurred.The ionic conductivity of the hydrogel soaked in saturated sodium chloride electrolyte for 6h and 1mol/L H₂SO₄ electrolyte for 4h reached the maximum value of 1.68S/cm and 0.83S/cm,respectively.Additionally,the 5mm-thick hydrogel reached swelling equilibrium after 12h,the volume and mass swelling rates of hydrogel were about 170% and 145%,respectively,and the elongation at break could reach about 200% at room temperature.

Polylactic acid (PLA) is a biodegradable polymer material,but its toughness is inadequate,thereby constraining its potential applications.In order to enhance the mechanical properties of PLA,this study blended PLA with poly (butylene succinate-co-terephthalate) (PBST),a polymer with good biodegradability and high flexibility.Additionally,N,N′-ethylenebis(stearamide) (EBS) was incorporated as a compatibilizer to optimize the compatibility between PLA and PBST.The results demonstrated that the introduction of EBS resulted in closer glass transition temperatures of PLA and PBST in the composite film.Furthermore,the dispersed phase size of the island structure in the composite film was reduced,indicating that the compatibility between PLA and PBST was improved.Moreover,after compatibilization modification,the tensile strength and elongation at the break of the composite film increased by 4.67% and 21.29%,respectively,and the water vapor transmission rate decreased by 12.92%.Meanwhile,the hydrophobicity of the composite film was improved.

This article reviewed the main progresses of poly(vinyl chloride) and focused on developing internal plasticization and reducing molecular chain defects.For the former,the solution includes:(1)the introduction of small_molecule plasticizing functional groups using nucleophile substitution reactions of C—Cl bonds in the PVC molecular chain and subsequent click reactions,etc.;(2)the introduction of large molecule graft chains using graft polymerizations of reactive C—Cl bonds;(3)the introduction of self_plasticizing functional monomers through free radical copolymerization,such as copolymers of vinyl chloride and (meth)acrylate polyethylene glycol monomethyl ether ester exhibited excellent internal plasticizing properties;and (4)controlled free radical polymerization synthesized block polymers,etc.The above technologies successfully produced PVC copolymers with varying glass transition temperatures (T_g).However,the high cost of the reactants and complicated operations made their application in industrial production challenging.In terms of industrial production technologies,the process factors affecting the grain morphology were discussed,with a focus on the continuous initiator dosing (CiD) technology,which could shorten the polymerization reaction time of PVC to 240min and significantly improved the thermal stability of PVC resins via reducing the content of tertiary C—Cl of the PVC chains.As a very important polymer to balance the chlorine of chloro_alkali industry,PVC resin remains irreplaceable for a considerable period.Improving production technologies,enhancing product quality,and developing new PVC copolymer resins are crucial for the sustainable development of the industry.

Inorganic-reinforced plant fiber polymer composites have become the focus of attention in the field of functional composites due to their advantages of excellent performance,high added value and wide application fields.In this paper,the research status and progress of inorganic-reinforced plant fiber polymer composites such as montmorillonite,mica,oxide,calcium carbonate,talcum powder,graphene,carbon black and carbon nanotubes in flame retardancy,aging resistance,electrical conductivity and electromagnetic shielding at home and abroad were systematically reviewed.It also proposed the existing problems of inorganic-reinforced composites in functional expansion,inorganic-matrix composite and functional internal mechanism analysis,and the development prospect of functional composites was prospected,aiming to provide a scientific basis for further promoting the research of high value-added functional composites.

With the depletion of traditional energy,hydrogen energy has become one of the most potential renewable energy options,and the use of biomass to produce hydrogen is a promising green method.At present,catalytic pyrolysis has gradually become the main research direction of biomass conversion and utilization technology,and hydrogen can be obtained directionally by selecting appropriate catalysts.In this paper,the production of high-content hydrogen by nickel-based catalysts was reviewed.The mechanism of catalytic pyrolysis and the effects of composite nickel-based catalysts (zeolite,metal oxide) on gas yield and composition were mainly introduced.In view of the current difficulties in this field,some prospects and development directions were put forward to provide important theoretical basis for biomass catalytic hydrogen production.

Carbon quantum dots (CQDs) as fluorescent nanoprobes for the detection of heavy metal ions have the characteristics of simple operation,low cost,high accuracy and fast response.The fluorescence quenching mechanism of CQDs fluorescent nanoprobes for the detection of heavy metal ions was introduced.The main factors affecting the performance of CQDs fluorescent nanoprobes were summarized.The problems existing in the detection of heavy metal ions by CQDs fluorescent nanoprobes were pointed out.Finally,the future development prospects of CQDs fluorescent nanoprobes were discussed.

Silicone materials have been widely used in aerospace,national defense industry and various industries of the national economy due to their excellent properties,such as high and low temperature resistance,weather resistance,electrical insulation,physiological inertness.The study of its depolymerization behaviour is helpful for the design and development of high-temperature resistant silicone rubber and the green recycling of waste silicone materials.The degradation mechanisms of silicone materials were reviewed,which mainly including catalytic degradation (nucleophiles,electrophiles) and thermal degradation (side-group thermo-oxidative degradation,main-chain zipper degradation,and main-chain random rearrangement degradation).The main approaches to inhibit and promote the degradation of silicone materials were described,aiming at improving the thermal stability of polysiloxanes and realizing the recycling of waste silicone materials.