Multifunctional Composite Materials Research Articles

Multi-functional flexible PANI-based material for the development of efficient heating sensing equipment: integrating intelligent heating, motion detection, moisture absorption and ultraviolet protection function

With the advancement of technology and the improvement of living standards, multifunctional composite materials are increasingly attracting attention. Conductive polymer polyaniline (PANI), a key component in the fabrication of intelligent composite materials, is widely used in various fields because of its unique properties. When FeCl3 was used as the oxidant, the PANI-based composite material demonstrated a significant increase in maximum saturation temperature from 34.10 °C to 47.43 °C, under a voltage range of 6–12 V. It also exhibited a sensitivity of 1.0960 kPa−1 (greater than 1 kPa−1) at a low pressure of 0.5 kPa, and its response/recovery time is 200 ms for both. Its maximum capillary rise height reached 7.7 cm. Additionally, the PANI-based composite material achieved a UPF value 40+, effectively blocking over 97.5 % of ultraviolet rays. It also absorbed over 90 % of electromagnetic waves within the 0–18 GHz frequency range. The wear resistance has also been significantly improved compared to pure cotton fabrics, with the friction times reaching 1370 before damage when FeCl3 is used as the oxidant for this composite material. The PANI-based composite material developed in this study functions of intelligent heating, motion detection, moisture absorption, and UV protection functions. It holds the potential to develop efficient heating and sensing devices, offering a solution for the design of the next generation of multifunctional flexible composite materials.

Self-encapsulation ultra-soft micro-channel with high thermal conductivity and passive radiation cooling

Oriented towards the industrialization of micro-electronic products, micro-channels suitable for micro and small electronic devices are committed to solving the issue of efficient thermal dissipation in the systems. Accordingly, research on integrating multifunctional thermal management composite materials for designing micro-channels has become a hot development trend. Notably, the design concept of efficient thermal dissipation micro-channel with the dual functional synergy of high thermal conductivity and passive radiation cooling was advanced. The compound of high thermal conductivity hexagonal boron nitride (h-BN) and high-elastic thermoplastic polyurethane (TPU) entrusts the micro-channel with a superb substrate with flexibility, stretchability, hydrophobicity, and high thermal conductivity. Draw support from a zero-energy consumption and environmentally friendly passive radiation cooling strategy, the micro-channel with a polyvinylidene fluoride/cellulose acetate (PVDF/CA) nanofiber film acquires an ultra-high reflectivity of up to 99.50 % (0.2–2.5 μm) and a high emissivity of 94.81 % (8–13 μm). The programmable patterned graphene oxide (GO) ink is assisted with high-viscosity natural Gleditsia sinensis polysaccharide (GSP) through 3D printing. Ultimately, a self-encapsulated, flexible, high thermal conductivity (0.42 W m-1K−1), passive radiation cooling micro-channel accumulated a temperature difference of 10.76 °C, potentially making a promising thermal management micro-channel system for development.

Elaboration and study of the fatigue behavior of a multifunctional composite material with embedded copper insert: The effect of thickness and electrical voltage

The behavior of multifunctional composite material with an embedded copper foil strip under cyclic loading was investigated. Materials able to bare charge as well as conduct electricity are crucial in various applications in high-tech industries. The effects of applied stress, voltage levels and the dimensions of the insert on the material response were analyzed. Two types of composites were prepared: one with a 0.1 mm thick copper (GFC0.1) and another with a thickness of 0.05 mm (GFC0.05). Both materials were subjected to tensile and fatigue tests. The results revealed that the dimensions of the insert had an impact on the Maximum Tensile Resistance (MTR). The examination of the fatigue-damaged composite gave important insights about the evolution of the de-bonding area of the interface copper/composite under different loading conditions. Fatigue test results allow the plotting of fatigue curves and establishing the fatigue equation specific to each material under each voltage level (U = 5, 9, and 12 ± 0.3 V). These results also showed that when tested at the same voltage, there is one stress level for which both GFC0.1 and GFC0.05 have the same fatigue resistance; above this stress value, GFC0.1 has a better resistance, and below it, GFC0.05 will be the one resisting better. Epoxy resin was chemically dissolved to restore the damaged copper Nicked-eye inspection along with scanning electron microscope (SEM) observations revealed interesting facts about the metallic insert behaviors, including the nature of the rupture and the effect of the voltage on the fractured surface aspect.

A polydopamine coated magnetic spiral switchable composite material for photothermal sterilization and dual-color fluorescence detection of food-borne pathogens

A multifunctional magnetic composite material (MSp@PDA) featuring with helical structure, superparamagnetism, photothermal properties, and fluorescence quenching capability was synthesized through sequential magnetization and in-situ polydopamine coating on the Spirulina surface, then applied for multi-scenario application of pathogens capture, sterilization, and sensitive detection. The pathogens capture and sterilization was investigated by loading bacterial broad-spectrum recognition molecule (MPBA) on MSp@PDA, the capture efficiencies of 91.6 % and 94.2 % were obtained for Escherichia coli and Staphylococcus aureus in 15 minutes, respectively, with complete photothermal sterilization achieved within 4 minutes. The fluorescence real-time detection of E. coli and S. aureus was realized by connecting dual-color fluorescent carbon dots to MSp@PDA through specific aptamers (dCD-apt-MSp@PDA), the corresponding detection limits were 2 and 3 cfu·mL−1, respectively, with linear ranges of 101∼107 cfu·mL−1. The spiked recovery rates of target bacteria in actual samples were 97.4∼101.1 % and 98.2∼101.4 % for E. coli and S. aureus, respectively. The constructed capture, sterilization, and fluorescence detection methods demonstrated promising application value for on-site monitoring of food-borne pathogens in complex matrices.

Reactive hyperbranched core-shell architecture for developing high-performance bio-based adhesive

Soybean meal (SM) adhesives offer a promising alternative to formaldehyde-based adhesives; however, their broader application is hindered by suboptimal adhesive properties and inadequate water resistance. In this study, we designed a novel reactive core-shell architecture (DAS@HBPA/EP) composed of dialdehyde starch (DAS) as the core and hyperbranched epoxy (HBPA/EP) as the shell, aimed at developing an SM adhesive with excellent water resistance, high bonding strength, and superior toughness. The reactive shell of DAS@HBPA/EP formed covalent bonds with protein molecules in SM, creating a highly interconnected structure that enhanced both the adhesive properties and water resistance of SM. Additionally, the microphase separation induced by the DAS core and the flexible hyperbranched shell provided the SM adhesive with improved toughness. As a result, plywood bonded with the SM/DAS@HBPA/EP adhesive exhibited exceptional dry shear strength (up to 2.14 MPa) and wet shear strength (1.24 MPa), representing a 589 % improvement over the pure SM adhesive. This performance is comparable to commercial melamine-urea-formaldehyde (MUF) resins (E0 grade). Furthermore, the SM/DAS@HBPA/EP adhesive showed a high residue rate (82.30 %) and low water absorption rate (0.94 %), along with a uniform and dense microstructure. This simple and cost-effective strategy presents a novel approach to advancing technological innovation in the development of multifunctional composite materials.

Research Progress and Application of Layered Rare Earth Hydroxides, a Class of Inorganic Layered Compounds with Photoluminescence.

Inorganic layered compounds are an important part of organic-inorganic functional nanocomposites and offer plentiful opportunities and possibilities for synthesizing new-style multifunctional materials because they could be intercalated, exfoliated, and swollen. In recent years, as inorganic layered materials with photoluminescence, layered rare earth hydroxides (LRHs) have been extensively studied. Due to their rich functionalization ways, they have been applied or shown potential application value in many fields such as pollution detection, biomedicine, photoelectric energy storage, and so on. On account of the basic physical and chemical properties, the basic structures of LRHs may be regulated through exfoliation and intercalation, which provides more possibilities for synthesizing new multifunctional composite materials and broadening and updating their application fields. In this paper, LRHs are extracted from inorganic layered compounds, and the structure, synthesis, research progress, and application of LRHs are summarized in detail, which lays a great theoretical foundation for further exploration and optimization of the application as a composite functional material in industry, medicine, detection, optoelectronics, and other fields.

Stretchable carbon nanotube/Ecoflex conductive elastomer films toward multifunctional wearable electronics

Conductive elastomer films (CEFs) have found widespread applications toward flexible electronics and wearable devices. Silicones are particularly advantageous for fabricating high-performance CEFs. However, processing silicone/conductive filler composite prepolymers is challenging because of their high viscosity, especially when incorporating nanofillers like carbon nanotubes (CNTs) that can greatly increase the viscosity of silicone prepolymers. Herein, we present a simple, facile and versatile hexane-assisted air-spraying method for fabricating silicone-based CEFs from Ecoflex and CNTs. This method allows for processing CNT/Ecoflex prepolymers with CNT concentrations of 0.5 ∼ 5 wt%, resulting in stretchable CEFs with controllable structural, mechanical and electrical properties. We leveraged the distinct advantages of CNT/Ecoflex CEFs, including the excellent mechanoelectrical sensitivity, workable strain range and elasticity of the CNT1/Ecoflex group, and the high conductivity and low mechanoelectrical sensitivity of the CNT5/Ecoflex group. These properties enable their multifunctional applications as wearable and waterproof resistive strain sensors, multilayered capacitive pressure sensors, and wearable electric heaters. This work provides valuable insights into the development of high-performance and multifunctional silicone-based composite materials for advanced wearable electronics.

A Flexible Organomagnetic Single-Layer Composite Film with Built-In Multistimuli Responsivity.

Materials possessing multiple properties and functionalities, that can be controlled or modulated by external stimuli, are a central focus of current research in materials sciences due to their potential to significantly enhance various future technological applications. Herein, we report a significant advancement in this field through the development of a smart, multifunctional organomagnetic composite material. By utilizing a thin layer of polydimethylsiloxane (PDMS) and polypyrrole (PPy) precursors, doped with nickel nanoparticles (NiNPs), we have created an innovative organomagnetic, PDMS/PPy/NiNPs (PPN), single-layer composite film that displays multistimuli responsivity. The study presents the first demonstration of a multifunctional flexible, three-component film structure integrating the structural and flexible PDMS component, together with a conductive polymer component and metal-based nanoparticles into a single-layer design, which displays enhanced and unprecedented responsivity properties against multiple different stimuli. Unlike typical stacked multilayered structures, that exhibit one or two functionalities at most, this novel configuration exhibits multiple functionalities, including magnetoresistance, mechanical stress response, piezoresistivity, and temperature change sensitivity. The as-prepared film demonstrates notable magnetoresistance responsivity, with a relative electrical resistance, ΔR/R0, changing under a weak magnetic field and under ambient conditions. The significance of our study lies in the film's versatility, stability, and sensitivity, especially within the physiological temperature range, making it highly relevant for future biomedical applications. Furthemore, the film's sensitivity to mechanical deformation reveals an impressive piezoresistance behavior. Unlike existing multilayer architectures of higher complexity, our single-layer thin film offers a simpler, more flexible, and reliable solution with a broad range of stimuli-sensing capabilities. The significance of this novel multiresponsive composite material is underscored by the growing demand for advanced materials in biomedical devices, magnetic switches, sensors, electronic skin, transistors, and organic spintronic devices. These promising organomagnetic self-standing layers provide a robust platform for future technological innovations.

The influence of CuxS particles on the thermal decomposition of anion exchangers

Due to the versality, surface imperfections and diverse redox chemistry of CuxS, hybrid ion exchangers (HIXs) containing these particles are an interesting object of research, including thermal transformation. The composite materials used for testing were strongly basic anion exchangers, with macroreticular (M) and gel-type structure (G), containing in the poly (styrene/divinylbenzene) skeleton fine particles of covellite/brochantite (M1), covellite (M2), covellite/digenite/djurleite (G1) and covellite/digenite (G2). The prepared HIXs contained 12–16 mass% S + Cu. They were subjected to thermal analysis under air and N2 to identify the role of the inorganic phase in decomposition of the polymeric phase. The results were discussed on the basis of the TG/DTG curves and X-ray diffraction (XRD) patterns of the solid residues (CuO after combustion, carbon/Cu2S after pyrolysis). It was found that CuxS in the resin phase exhibited oxidative activity promoting the combustion process. The polymeric skeleton of HIXs decomposed in air at a much lower temperature compared to pure resins (400 vs 600 °C). The TG/DTG curves had a model shape, three separate conversions occurring in a narrow temperature range, which indicated sequential decomposition. The low consumption of hydrogen for the reduction of CuxS to Cu2S during pyrolysis was not conducive to condensation of alkyl radicals and increase of the mass of carbon matter. The results advance the understanding of the effect of copper/sulfur-containing fine particles on the thermal decomposition of anion exchanger and can be useful in preparation of multifunctional carbon-containing composite materials.

Multifunctional composite phase change material with electrostatic self-assembly structure based on carboxylated multi-walled carbon nanotubes

The need for improved thermal regulation in electronic devices and solar thermal energy storage, prompted by the energy crisis, has expedited the advancement of phase change materials (PCMs). Carboxylated multi-walled carbon nanotubes (MWCNT-COOH) were produced by introducing carboxyl functional groups onto MWCNTs utilizing a concentrated acid treatment. The novel composite was engineered through an electrostatic self-assembly process between the negatively charged MWCNT-COOH and the positively charged Poly dimethyl diallyl ammonium chloride (PDDA) solution, filling the structure with the PCM polyethylene glycol (PEG) and incorporating the (magnesium hydrate) Mg(OH)2 to enhance the material's flame resistance at high temperatures. The thermal conductivity of the obtained composites improved significantly from 0.25 W/m·K to 1.183 W/m·K, while maintaining an enthalpy of phase transition of phase change of 135.1 J/g. Owing to the capillary effect of the closely packed MWCNT-COOH tubular structure, the composite material exhibited excellent high-temperature shape retention ability. Additionally, the composite demonstrated high absorption with an absorbance reaching 1.18 L/(g·cm) and composite materials can convert up to 86.8 % of light energy into heat energy.

Facile Preparation of Cross-Linked Moringa oleifera Seed Hulls Powder/Hydroxyapatite Framework Composite for Efficient Removal of Toluidine Blue and Methyl Violet 2B from Aqueous Solution

AbstractIn this study, adsorption of two cationic dyes, Toluidine Blue (TB) and Methyl violet 2B (MV 2B) from an aqueous solution was achieved by using multifunctional composite material. The formulation of the composite (MO@HA) was obtained by using Moringa oleifera seed hull powder, calcium chloride (CaCl2), and ammonium hydrogenophosphate (NH4)2HPO4 salts. Surface morphology, functional groups, specific surface area, and surface charge of the composite were explored using Scanning electron microscopy (SEM), Fourier Transform infrared spectroscopy (FTIR), BET analysis, and point of zero charge (PZC), respectively. The composite material resulted in a structural change in the surface of the adsorbents, increased oxygen vacancies, enhancement of active sites, and a specific surface area of 735.55 m2 g−1. Different adsorption parameters such as pH, contact time, adsorbent dosage, and initial concentration were evaluated. The adsorption study showed that equilibrium was reached after 60 min, and the optimum adsorption pH for both dyes (TB and MV 2B) was 6. Langmuir, Freundlich, Liu, and Temkin were fitted to describe the adsorption isotherm, both TB and MV 2B had best correlation with Liu isotherm. The maximum adsorption capacity of TB and MV 2B were 341.488 and 182.453 mg g−1, respectively. Adsorption-desorption cycling studies on the adsorbent confirmed its regeneration and reusability after 5 cycles. A possible adsorption mechanism involving electrostatic interactions, n-π bonding, and hydrogen bonding was suggested. These findings highlight a new direction in the development of efficient and sustainable adsorbent in environmental remediation, specifically in the removal of dyes from aqueous solution.

Densification, deformation, and delamination during co‐sintering process of metal–ceramic laminates

AbstractToday, there is a high demand and increasing trend for multifunctional composite materials and components due to the combination of a wide range of favorable properties. However, undesired deformation leading to delamination, curvature, cracks, or even complete fracture frequently occurs during the co‐sintering process of metal–ceramic laminates (MCLs). To solve these issues, experimental work highly relies on the time‐consuming trial‐and‐error principle. This work aims to develop a thermo‐mechanical‐metallurgical model capable of predicting the densification, deformation, and delamination of MCLs during the co‐sintering process. It is found that the developed model successfully considers the inhomogeneous relative density distribution and phase transformation of the steel tape. In addition, a thin interlayer formed by a mixed slurry in the MCLs is modeled as cohesive elements to simulate the delamination process. The developed model is systematically validated by the experimental measurements and observations in terms of densification, deformation, and delamination during the co‐sintering process of the investigated laminate variants.

Novel electrochromic-supercapacitor device based on P(TPACz)/WO3-PDA nanocomposite film

Organic–inorganic composites of (E)-3,5-di(9 H-carbazol-9-yl)-N-(4-(diphenylamino)benzylidene)aniline/dopamine-modified WO3 (P(TPACz)/WO3-PDA) were prepared by electrochemical polymerisation. The as-prepared P(TPACz)/WO3-PDA composites showed good electrochromic and electrochemical performance. The prominent electrochemical performance of P(TPACz)/WO3-PDA represents a high areal capacitance (32.15 mF cm−2 at 0.1 mA cm−2) and wide range of potential windows (-2.0−1.6 V). Additionally, symmetric supercapacitor devices based on P(TPACz)/WO3-PDA composite films were successfully constructed, which exhibited a high specific capacitance (13.88 mF cm−2 at 0.02 mA cm−2) and an energy density of 7.71 × 10−3 mWh cm−2 in n-doped station. The remarkable electrochromic and electrochemical performances are due to the synergy between the organic polymer and WO3-PDA. A complete large-area composite film structure with high conductivity promises fast electronic transport. This study provides a method for preparing multifunctional composite electrode materials, offering technical support for intelligent displays and energy storage technologies.

Real-scale experiments of resistive heating laminate composite panels for radiant heating in railway vehicles

Railways, as one of the representative mass transit systems, are vulnerable to highly contagious respiratory diseases due to their operation in densely populated environments. Notably, the current convective heating system creates an environment susceptible to virus transmission within railway vehicles. To improve this situation, there have been attempts to introduce radiant heating systems to reduce the risk of virus transmission and create a comfortable indoor environment. Previous studies focused on developing radiant heating composite material for railway vehicles by incorporating a carbon fiber heating element within a glass fiber composite to enable heat generation through joule heating. However, this development was limited to the specimen level. In contrast, this study aims to demonstrate their applicability and performance for actual railway vehicle parts at the component level. Specifically, resin flow and manufacturability were analyzed to assess applicability to railway vehicles. Additionally, heating performance and heat flow characteristics were evaluated to determine heating effects. Based on these results, it is anticipated that the application of multifunctional composite materials in the railway industry will improve the vulnerability to winter viruses and indoor environments and expand the utilization of multifunctional composite materials in various fields.

Laser‐Induced Transformation of ZIF‐8 into Highly Luminescent N‐Doped Nanocarbons for Flexible Sensors

AbstractMetal–organic frameworks (MOFs) like the zeolitic imidazolate framework (ZIF‐8) have a high surface area, tunable porosity, and robust thermal and chemical stability, making them attractive candidates for various applications. Here, a strategy is shown that spans that functionality and provides strong photoluminescence (PL) emission, unlocking ZIF‐8‐based materials for chemical and temperature sensors based on PL. The approach is based on laser processing that dramatically boosts the PL response of laser‐irradiated ZIF‐8 (LI ZIF‐8), achieving a 70‐fold increase in intensity relative to the pristine material. The PL characteristics of the irradiated material can be easily tuned by varying the laser power and irradiation time with in situ and real‐time spectroscopic analysis providing insights into the process dynamics. It is found that the observed PL enhancement is primarily due to the laser‐induced transformation of ZIF‐8 into nitrogen‐doped nanocarbons and ZnO nanostructures. The versatility of this laser processing approach is leveraged to create flexible electronics by integrating the LI ZIF‐8/nanocarbon architectures into thermoplastic polyurethane (TPU). The multifunctional composite material shows excellent performance as flexible electrodes for human‐body monitoring applications, as well as both temperature and flexure sensors with remarkable mechanical resilience.

Development of flexible nanocellulose-based composites with enhanced hydrophobicity and improved haze for efficient light management in solar cells

The proliferation of flexible electronic products derived from petroleum substrates in the market has exacerbated environmental pollution stemming from electronic waste generation. As a result, there is an increasing demand for cellulose nanofiber substrates that are green and degradable. However, substantial challenges remain in addressing the hydrophilicity of nanocellulose substrates and optimizing their optical properties for commercial viability. In this study, we propose a multifunctional composite film material through the use of amidation modification and biomineralization technology. We successfully grafted highly carboxylated transparent oxide nanocellulose (TCNF) and octadecylamine (ODA) using carefully designed amidation conditions. Through the carboxyl group after amination, we were able to generate amorphous calcium carbonate (ACC) in situ, resulting in the creation of a flexible, sustainable, and transparent TCNF/ODA/CaCO3 composite film with high hydrophobicity and haze. This was confirmed by a water contact angle value of 138.21° and a haze value of 84.8%. The composite film exhibits low surface energy and high dual-scale surface roughness, while its internal structure is relatively porous and loose, but still possesses multi-scale interface interactions. We demonstrate a strong correlation between the multifunctional properties and structural properties of the composite films in this work, thereby achieving effective light management applications in solar cells. Our findings are expected to provide new insights and ideas for the design of multifunctional green flexible solar cell device substrate materials.

Fabrication of Cross‐Linked Polyimide Hollow Microspheres With Lightweight, Thermal Resistance and Controllable Size

AbstractPolyimide (PI) hollow microspheres possess lightweight and excellent thermal resistance, which are widely used in microreactors, catalysis, adsorption separation, high‐temperature insulation, and so on. In this manuscript, PI hollow microspheres are fabricated by constructing a crosslinked structure combined with gradient heating. The formation of PI hollow microspheres includes gas nucleation, expansion, and imidization. The PI hollow microspheres size is controlled by adjusting polyester ammonium salts size, and microspheres size is distributed in 309–956 µm. PI hollow microspheres have lightweight, excellent heat resistance and carbonization performance, bulk density, initial decomposition temperature, and weight residue at 800 °C is 87.3–178.6 kg m−3, 533.6 °C and 59.8%. The PI hollow microspheres have potential applications in high‐temperature resistant and multifunctional composite materials preparation. Moreover, this method is simple, efficient, and highly operable, which can be used for large‐scale production of PI hollow microspheres.

INVESTIGATION OF THE MECHANICAL AND TRIBOLOGICAL BEHAVIOURS OF CUPOLA SLAG AND MWCNT-REINFORCED EPOXY HYBRID NANOCOMPOSITES: A SUSTAINABLE APPROACH FOR ENVIRONMENTAL PRESERVATION

This experimental investigation explores the mechanical and tribological characteristics of cupola slag (CS) and multiwall carbon nanotubes (MWCNTs) reinforced hybrid nanofiller epoxy composites. Cupola slag is an industrial by-product that is generated during the melting of cast iron. The disposal of slag residues in landfills results in environmental pollution. In the context of environmental preserving as well developing new engineering composites material from waste to resource. MWCNTs possess an excellent strength-to-weight ratio, high stiffness, and thermal properties. The mechanical and tribological characteristics of the hybrid nanocomposites comprising epoxy were examined by varying the weight fraction of fillers composed of CS and MWCNTs. The experimental results indicated that the ECSM3 hybrid nanocomposites have superior tensile strength and the flexural modulus improved by 92 % and 78 % respectively when compared with epoxy. Similarly, the tribology performance of the ECSM3 exhibited improved specific wear resistance of 97 %, 106 % and 88 % on the dry-sliding loads of 10 N, 20 N and 30N, respectively. A morphological analysis was carried out on fractured and worn surfaces of the specimen to understand the homogeneous dispersion and matrix-interlocking mechanism between the hybrid nanofillers and the epoxy matrix. The integration of CS alongside MWCNTs for the fabrication of epoxy hybrid nanocomposites represents a stride towards sustainable and eco-friendly technology in the production of multifunctional composite materials for diverse engineering applications.

Integrated Thermal Conductive and Electromagnetic Interference Shielding Performance in Polyimide Composite: Impact of Carbon Felt-Graphene Van der Waals Heterostructure.

With the widespread application of highly integrated electronic devices, the urgent development of multifunctional polymer-based composite materials with high electromagnetic interference shielding effectiveness (EMI SE) and thermal conductivity capabilities is critically essential. Herein, a graphene/carbon felt/polyimide (GCF/PI) composite is prepared through constructing 3D van der Waals heterostructure by heating carbon felt and graphene at high temperature. The GCF-3/PI composite exhibits the highest through-plane thermal conductivity with 1.31 W·m-1·K-1, when the content of carbon felt and graphene is 14.1 and 1.4 wt.%, respectively. The GCF-3/PI composite material achieves a thermal conductivity that surpasses pure PI by 4.9 times. Additionally, GCF-3/PI composite shows an outstanding EMI SE of 69.4dB compared to 33.1dB for CF/PI at 12GHz. The 3D van der Waals heterostructure constructed by carbon felt and graphene sheets is conducive to the formation of continuous networks, providing fast channels for the transmission of phonons and carriers. This study provides a guidance on the impact of 3D van der Waals heterostructures on the thermal and EMI shielding properties of composites.

The intrinsic flame retardant multifunctional composite phase change material with phosphorus pentoxide for battery thermal safety system

The temperature distribution has severely affected the performance of lithium-ion battery modules in electric vehicles (EVs), composite phase change material (CPCM) with excellent temperature controlling function as a passive battery thermal management system is essential to ensure the safety of battery module. In this study, the polyethylene glycol phosphate ester (PEGP) has been synthesized by esterification of phosphorus pentoxide and polyethylene glycol through the reaction of PEGP and melamine (MA), the network crosslinking structure has been built to greatly improve the anti-leakage performance. The flame-retardant CPCM containing PEGP/expanded graphite /epoxy resin/MA (PPEM) has been successfully designed and prepared. The results indicate that PPEM2 containing 20 wt% melamine and 7 wt% epoxy resin exhibit excellent antileakage and prominent flame retardant properties comprehensively. It should be noted that the peak heat release rate of PPEM2 has been reached to 352.41 KW/m2, which is obviously decreased by 47.55 % comparing with pure PEG. The main reason is that the grafting flame retardant elements (P) and melamine onto polyethylene glycol molecular chain by chemical reaction. In addition, it can maintain the operating temperature below 36 °C at 23 A discharge current. The battery module with PPEM2 can transfer the heat timely and promptly, exhibiting outstanding flame-retardant effect to avoid thermal runaway. With these prominent performances, this intrinsic flame-retardant CPCM can not only exhibit an excellent thermal management effect but also provide a promising approach to inhibit the thermal runaway propagation.