Flame Retardant Agent Research Articles

Nano-layered double hydroxides as efficient endothermic, strengthening, and flame-retardant agents for fly ash/polyurethane composite materials

Polyurethane (PU) grouting materials in coal mining must possess essential mechanical properties and exhibit low heat release and high flame retardancy to enhance the safety and efficiency of coal mining. In this study, fly ash (FA) and nano-layered double hydroxides (LDH) were utilized as fillers to prepare a series of PU/FA/LDH composite grouting materials. Results showed that incorporating 2.5 % LDH reduced the maximum reaction temperature by 26.7 °C and decreased heat release from 177.45 J/g to 108.37 J/g compared to PU grouting material. These reductions were attributed to the uniform dispersion of LDH, which enabled the endothermic removal of plentiful adsorbed water during the curing process. However, exceeding 2.5 % LDH caused agglomeration, encapsulating the water and increasing the maximum reaction temperature. The effective fraction of closed cells in the PU/FA/LDH composite grouting materials was tailored by increasing the content of LDH, leading to enhanced compression strength. Moreover, cone calorimetry revealed that LDH was more effective in reducing the heat release during the combustion process of PU grouting materials, while FA was more effective in reducing smoke production. This synergistically enhanced the flame retardancy of the PU grouting materials. This work provides an effective way to produce high-strength, flame-retardant grouting materials at lowered reaction temperatures.

Phosphorylated chitosan polymer as flame retardant and antimicrobial agents for cotton and cotton-polyester blends fabrics

Phosphorylated chitosan polymer as flame retardant and antimicrobial agents for cotton and cotton-polyester blends fabrics

Toward a green economy: Lignin-based hybrid materials as functional additives in flame-retardant polymer coatings

This study describes the combination of unique properties of lignin with TiO2 as an innovative and effective preparation method for high-performance flame-retardant additives that may be utilized as polymer coatings. The use of lignin resulted in numerous advantages including an increased number of functional groups, satisfactory biocompatibility, low toxicity, and high carbon content. The major benefit of lignin is associated with the reduced carbon footprint of the manufactured product. Lignin can be classified as a natural flame-retardant agent owing to the high amount of char formed during combustion. In turn, TiO2 exhibits high chemical stability and low operating costs and is considered a non-toxic and environmentally friendly material. During the experiments, commercial TiO2 in anatase crystallographic form, TiO2 synthesized from titanyl sulfate hydrate, and kraft lignin as well as organic–inorganic hybrid materials composed of these materials were evaluated as functional additives in epoxy-resin-based polymer coatings (Epidian 601) and their properties were investigated in detail. The cone colorimetry test confirmed that the obtained hybrids are effective flame-retardant additives for polymer coatings, with a notable fire hazard reduction observed for samples containing a synergistic system of titanium oxide and lignin. The coating with lignin was the most effective in fire suppression processes. The conducted thermal and mechanical investigations confirmed good performance properties of the coatings indicating thermal resistance up to 360 °C and Shore D hardness in a range of 80.36–86.28°Sh, accordingly. Optical profilometry investigations show that the lignin/TiO2 hybrids exhibit a stable topological surface shape as well as good dispersion and uniformity in the polymer matrix. All the conducted tests allowed confirmation that the presence of functional additives in polymer coatings in the form of lignin and TiO2 can be a promising alternative to non-biodegradable synthetic materials which improve flame-retardant properties.

Small-scale experimental study on EPS ETICS and flame-retardant coating reaction-to-fire performance

External thermal insulation composite systems (ETICS) are a common and energy-efficient cladding system. Thermoplastic expanded polystyrene (EPS) is widely used as an insulation core. However, such combustible material has aggravated fire incidents in recent years, thus it is essential to improve its fire behavior. To evaluate the performance of EPS ETICS, a series of specimens with different flame-retardant (FR) coatings were tested using a small-scale bench and a mass loss calorimeter with a maximum heat flux of 40 kW/m2. When untreated EPS ETICS are exposed to heat, the EPS foam degrades, releases a large volume of combustible gases, and ignites. Applying FR agents such as FR surface paint and expandable graphite blended coating can stop flame propagation, reduce total heat release by approximately 50%, and preserve about 50% of the EPS foam during heat exposure. This enhances significantly the fire safety of EPS ETICS.

MULTIFUNCTIONAL MODIFICATION OF COTTON FABRIC FOR ANTIMICROBIAL, FLAME-RETARDANT AND OLEOPHOBIC PROPERTIES

In recent times, the investigation and development of multifunctional textiles have become a necessity for the textile and apparel industries. Therefore, this paper explores an innovative approach to enhancing the functional properties of cotton (cellulosic) fabric by integrating advanced technologies to impart oleophobic/hydrophobic, flame-retardant, and antibacterial characteristics. The methodology involves systematically applying chemical treatments utilizing a layer-by-layer finishing technique to achieve the desired multifunctionality in cotton fabric. Silver nanoparticles and a phosphorus-nitrogen-based synergistic flame-retarding agent were employed to finish the fabric. Performance testing encompasses evaluating bacterial reduction, contact angle measurements, water absorption properties, flame-retardant capabilities, and Limiting Oxygen Index (LOI). Characterization techniques such as FTIR, SEM, and EDX analysis, were carried out to assess structural and chemical modifications of the material. The results illustrate a notable transformation of the cellulosic fabric, showcasing enhanced resistance to bacterial attack, improved stain resistance, and heightened flame-retardant performance, without compromising its color indices and air permeability. The fabric retains these multifunctional attributes even after 20 cycles of laundering, which confers durability. The implications of this research extend the application of conventional cotton fabric in diverse sectors, including apparel, home furnishings, and industrial textiles.

Comparision of the Effectiveness of Fire-proof Impregnation Methods for Scots Pine Wood Used in Buildings Construction

The fight for a healthy and clean climate forces many restrictive changes to European law. Wooden construction fits very well into these changes, as it is able to store carbon dioxide for years. Unfortunately, many regulations, e.g. fire regulations, still hinder the development of this type of structures in Poland. Wooden elements used that have class D must achieve class B of fire resistance. For this purpose, they are modified with flame retardant agents. Three salt flame retardants based on: 1-phosphorus and iron, 2-phosphorus and nitrogen and 3-ogranic componds including benzoates, were used in the tests. The amount of applied fire retardants was compared depending on the impregnation technology used: surface immersion and pressure, as well as the reaction to fire of impregnated wooden elements. As a result of the tests, no impregnation used improved the fire properties, as shown by a small-scale cone calorimeter test. The project results indicate the need to conduct new basic research on the possibility of permanently improving the fire properties of wooden elements, which would allow the widespread use of wood in construction.

Bio-functionalization of fillers with natural phytic acid for sustainable flame-retardant agents for natural rubber composites

The current challenge for sustainable flame retardants has led to innovative approaches, including the utilization of natural substances to enhance the fire resistance of elastomer composites. This paper presents the design of eco-friendly hybrid flame-retardant additives based on mineral fillers (hydrotalcite (LDH) and sepiolite (SEP)) modified with aminosilane (APTS) and phytic acid (PA) for natural rubber (NR) biocomposites. The synergistic effects of the PA and silanized mineral fillers resulted in NR composites with improved thermal, mechanical, and barrier properties, as well as increased flame retardancy. Importantly, it was proven that direct in-situ application of PA into elastomer cured with sulphur-based crosslinking systems is ineffective, due to its negative effect on the curing process (significantly reducing torque moment). Binding the PA onto silanized fillers enabled the creation of hybrid additives that leverage the flame-retardant benefits of PA without compromising the other properties of the polymer. The addition of PA-modified fillers to NR reduced the heat release rate (HRR) by around 40 %, indicating outstanding flame retardancy. This work makes a significant contribution and expands the understanding of using eco-friendly natural compounds to reduce the flammability of sulfur-cured elastomers.

Plasma‐assisted incorporation of flame‐retardant chemicals for improved flame retardancy of polyester fabrics

AbstractThe polyester fabric was subjected to atmospheric plasma and impregnated with commercially available 3‐hydroxyphenyl phosphinyl‐propanoic acid (3HPP) as flame retarding agent by high‐temperature high pressure (HTHP) dyeing method. Various concentrations of 3HPP in water, up to 4% w/v, were applied using the HTHP method. It was observed that the plasma treatment not only enhanced wettability and wicking but also facilitated increased pickup of 3HPP onto the polyester. The treatment exhibited a noteworthy enhancement in the limiting oxygen index (LOI), rising from 20.8% for the untreated control fabric to 30% for the fabric treated with plasma and a 4% 3HPP solution. Additionally, the application of 3HPP without plasma treatment did not yield significant improvements in flame‐retardant (FR) properties. The combined treatment of plasma and 3HPP resulted in an LOI of 29% with a 2% 3HPP treatment, while at the same concentration without plasma treatment, the LOI value was 26.8%. The heightened LOI was primarily attributed to the presence of phosphorus, as confirmed by high‐performance liquid chromatography and energy‐dispersive X‐ray spectroscopy. Additionally, the wash durability assessment of plasma‐processed and 3HPP‐treated samples demonstrated sustained flame retardancy, with an LOI of approximately 28% even after undergoing 20 wash cycles. Vertical flammability and cone calorimetry also confirm improved FR properties after treatment. Remarkably, the mechanical properties and surface morphology of the fabric remained unaltered following both plasma and chemical treatments.Highlights Easy and cost‐effective technique for the downstream process for FR polyester fabric. FR agent during polymerization has the disadvantage of lower molecular weight. Potential for producing FR industrial polyester fabric. Post‐plasma treatment improves the washing fastness. The mechanical and comfort properties remain intact during the process.

Multi-functionalization and recycling of basalt fibre/polypropylene laminated composites based on mixed plain-woven fabric and related interfacial decorations

The development of laminated composites of thermoplastic polypropylene (PP)/continuous basalt fabric is limited by poor mutual infiltration and weak interfacial interactions between the matrix and fabric, as well as the intrinsic flammability and susceptibility of the PP matrix to ultraviolet (UV) aging. To solve the above shortcomings in a high-efficiency manner, a multi-functional transition layer was constructed between the PP matrix and long basalt fibres (LBFs) based on a hybrid plain-woven fabric composed of LBFs weft yarns and PP warp yarns. After hot-laminating these hybrid plain-woven prepregs, the mechanical performance of the resultant laminates was optimised and strengthened by selecting the compositions of the multi-functional transition layers (comprising flexible alkyl glycidyl ether chains, various rigid inorganic nanoparticles, or a flexible-rigid hybrid layer). Among these different transition layers, the interface between the LBFs-g-MWCNTs-OH and the PP matrix presented better mutual infiltration due to the lower interfacial energy, stronger mechanical engagement effect derived from the rougher fibre surface, and higher interfacial modulus. Therefore, the fewer structural defects and more effective transfer of the applied load at the interface caused the tensile strength/modulus and flexural strength/modulus of the related hybrid weaving laminates (HWLs) to reach 278.1 MPa/31.8 GPa and 264.2 MPa/12.4 GPa, respectively. The rigid interfaces formed by the deposited nanoparticles also accelerated heat transfer from the matrix to the fibre and the absorption of UV-light inside composite, then improving the flame-retardancy and anti-UV aging performances of the corresponding HWLs. Finally, recyclability evaluations indicated that the waste LBFs-g-SiO2/PP HWLs can be used as anti-UV aging and flame-retardant agents to fabricate new modified PP pellets with multiple functions.

Construction of Fire Safe Thermoplastic Polyurethane/Reduced Graphene Oxide Hierarchical Composites with Electromagnetic Interference Shielding.

Incorporating outstanding flame retardancy and electromagnetic interference shielding effectiveness (EMI SE) into polymers is a pressing requirement for practical utilization. In this study, we first employed the principles of microencapsulation and electrostatic interaction-driven self-assembly to encapsulate polyethyleneimine (PEI) molecules and Ti3C2Tx nanosheets on the surface of ammonium polyphosphate (APP), forming a double-layer-encapsulated structure of ammonium polyphosphate (APP@PEI@Ti3C2Tx). Subsequently, flame-retardant thermoplastic polyurethane (TPU) composites were fabricated by melting the flame-retardant agent with TPU. Afterwards, by using air-assisted thermocompression technology, we combined a reduced graphene oxide (rGO) film with flame-retardant TPU composites to fabricate hierarchical TPU/APP@PEI@Ti3C2Tx/rGO composites. We systematically studied the combustion behavior, flame retardancy, and smoke-suppression performance of these composite materials, as well as the flame-retardant mechanism of the expansion system. The results indicated a significant improvement in the interface interaction between APP@PEI@Ti3C2Tx and the TPU matrix. Compared to pure TPU, the TPU/10APP@PEI@1TC composite exhibited reductions of 84.1%, 43.2%, 62.4%, and 85.2% in peak heat release rate, total heat release, total smoke release, and total carbon dioxide yield, respectively. The averaged EMI SE of hierarchical TPU/5APP@PEI@1TC/rGO also reached 15.53 dB in the X-band.

Construction of durable flame retardant, anti-dripping, and smoke-suppressing recycled polyester fabric

Recycled poly(ethylene terephthalate) (R-PET) fabrics offer a sustainable and eco-friendly alternative to virgin PET but exhibit high flammability and increased smoke emission. In this study, magnesium hydroxide nanoparticles (nano-Mg(OH)2) with the particle size of 53 nm were synthesized and combined with cyclic phosphate ester through high-temperature and high-pressure immersion technology. The organic‒inorganic flame retardant (FR) agents were expected to penetrate the R-PET fibers, thus achieving high washing durability for flame retardancy and smoke suppression. The surface structural performance of nano-Mg(OH)2 and the smoke and heat suppression capacity, FR performance, mechanism and laundering resistance of the modified R-PET samples were also explored. The organic‒inorganic FR system significantly improved the FR properties and anti-dripping ability of R-PET while significantly reducing smoke and heat generation. Moreover, the modified R-PET fabrics exhibited self-extinguishing ability even after 40 washes, indicating their high washing resistance. The organic‒inorganic FR system was effective in both gas and condensed phase, providing multilevel fire safety. This study provides efficient and durable FR-functionalized R-PET fabrics with low smoke suppression and high fire safety.

Innovative multifunctional fire retardance of poly(butylene adipate-co-butylene terephthalate)-based bio-composite formulation

Poly(butylene adipate-co-butylene terephthalate) (PBAT), a biodegradable aromatic-aliphatic copolyester, has been widely applied in various fields, but it shows the flammability, resulting in serious fire risk. The flame retardancy of some PBAT/polymer blend systems have been studied, but that of neat PBAT was seldom reported. In particular, the research and development of the bio-based green flame retardant agent is highly desired. In this work, fully bio-derived modified chitosan particles (C-CS), were synthesized and used to prepare a novel PBAT-based multifunctional flame-retardant composite. The PBAT/3%C-CS composite (PC3) exhibited an excellent anti-dripping and self-extinguishing performance and achieved the highest fire safety rating (V-0). Peak of heat release rate and total heat release reduced by 39.8 % and 14.9 %, respectively. The char residue yield of the PC3 increased by 211.6 % in the PC3, compared with that of neat PBAT. Both condensed- and gas-phase played dual roles on increasing the flame-retardant performance of the PC3. The PC3 showed a relatively compact and continuous char layer which acted as a physical barrier to suppress the heat exchange and O2 entry (into the matrix) in the combustion process. Meanwhile, the concentration of O2 and H·/HO· free radicals were diluted by a small portion of non-flammable gas products in the pyrolysis process. Also, the PC3 presented elevated crystallizability and anti-bacterial effect, and reduced UV-transmittance characteristic.

Research Progress in Flame Retardant in Flame Retardant Coatings

Flame retardant coatings are functional materials that can serve as decorative and protective substrates in the event of a fire. Flame retardant coatings generally consist of two parts: a base material and a flame retardant agent. A detailed introduction was given to the development of flame retardant coatings in recent years and the flame retardants used in flame retardant coatings. Flame retardants mainly include halogen flame retardants, phosphorus nitrogen flame retardants, expansion flame retardants, biomass flame retardants, and graphene flame retardants. The application of flame retardant coatings in the fields of epoxy resin, polyurethane, etc. was elaborated. In addition, the application of new biomass flame retardants and graphene flame retardants was introduced, and the future development of flame retardant coatings and flame retardants was described.

Engineering Sulfur-Containing Polymeric Fire-Retardant Coatings for Fire-Safe Rigid Polyurethane Foam.

With the advantages of lightweight and low thermal conductivity properties, polymeric foams are widely employed as thermal insulation materials for energy-saving buildings but suffer from inherent flammability. Flame-retardant coatings hold great promise for improving the fire safety of these foams without deteriorating the mechanical-physical properties of the foam. In this work, four kinds of sulfur-based flame-retardant copolymers are synthesized via a facile radical copolymerization. The sulfur-containing monomers serve as flame-retardant agents including vinyl sulfonic acid sodium (SPS), ethylene sulfonic acid sodium (VS), and sodium p-styrene sulfonate (VSS). Additionally, 2-hydroxyethyl acrylate (HEA) and 4-hydroxybutyl acrylate are employed to enable a strong interface adhesion with polymeric foams through interfacial H-bonding. By using as-synthesized waterborne flame-retardant polymeric coating with a thickness of 600µm, the coated polyurethane foam (PUF) can achieve a desired V-0 rating during the vertical burning test with a high limiting oxygen index (LOI) of >31.5vol%. By comparing these sulfur-containing polymeric fire-retardant coatings, poly(VS-co-HEA) coated PUF demonstrates the best interface adhesion capability and flame-retardant performance, with the lowest peak heat release rate of 166kW m-2 and the highest LOI of 36.4vol%. This work provides new avenues for the design and performance optimization of advanced fire-retardant polymeric coatings.

The investigation of flame-retardant fiber mats for high performance composites: flame retardancy and structure performance

The flame-retardant performance of carbon fiber reinforced composites serves as a critical metric for structural stability. Nonetheless, the prevalent methodologies for improving the flame retardancy of composites struggle to reconcile the dual objectives of flame retardancy and mechanical robustness, due in part to the constraints imposed by the conventional additive-based approach on the material interface. This study introduced a novel method involving a glass fiber mat, which was augmented with a polyurethane-based treatment integrated with flame-retardant substances, in particular ammonium polyphosphate and nickel hydroxide. This fiber mat was strategically applied to the composite surface, conferring both flame retardancy and enhanced structural resilience. The structure performance and flame retardancy of composites were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and the cone calorimeter test. Experimental comparisons with nontreated controls indicated that the innovative composites exhibited a reduction in total heat release and total smoke production by 13.7% and 18.8%, respectively. Concurrently, a notable enhancement in mechanical properties was observed, with increases of 20.9% and 23.1% for tensile and flexural strength. This well-balanced performance is attributable to the structure design, with toughened glass fiber mats to protect the composite surfaces from structural failure, and flame-retardant agent composition for combustion resistance and smoke suppression. Consequently, the proposed integrative flame-retardant structural design, enriched with specific flame-retardant treatments, offers a promising avenue for fabricating high-performance composite materials with potential utility in the aviation and aerospace sectors.

Development of test methods for fire-retardant coatings of steel engineering structures during operation

Introduction. Prediction of the durability of flame-retardant coatings of steel engineering structures and preservation of their performance during operation remain important research directions. There is a lack of normative documents in the field of fire protection, regulating the process of testing of flame-retardant coatings during operation, as well as determination of their durability (service life).Aim. To develop test methods for determining the resistance of flame-retardant coatings of steel engineering structures exposed to climatic factors, preservation of their fireproof and anti-corrosion properties during operation.Materials and methods. Test specimens included 600 x 600 x 5 mm plates made of 08kp and 08ps sheet steel according to State Standard 16523-97 and State Standard 9045-93 with a flame-retardant agent applied on the front side.Results. Methods for testing thin-layer intumescent and structural flame-retardant coatings during operation are proposed. The methodology of accelerated climatic testing of specimens coated with thin-layer intumescent flame-retardant coatings (flame-retardant paints) corresponds to State Standard 9.401-2018. These coatings are inherently high-solid paint materials. A new methodology, sequence, and modes of testing are developed for structural flame-retardant coatings. The subsequent assessment of fireproof properties of coatings and their preservation is carried out by the methods of fire protection efficiency according to State Standard R 53295-99 and the methods of thermal analysis. These methods imply comparison of the characteristics of the initial flame-retardant coating and those obtained after sample aging. The preservation of fireproof properties by thin-layer intumescent and structural coatings is additionally evaluated by the intumescence coefficient and the change in thermal conductivity, respectively.Conclusions. Test methods for flame-retardant coatings of steel engineering structures during operation are developed. Threshold levels of changes in their properties are established. After accelerated climatic tests, fire protection efficiency should not decrease by no more than 20 %. For structural fire protection, an increase in thermal conductivity by no more than 5 % is permitted. For thin-layer coatings, the arithmetic mean value of the intumescence coefficient should not decrease by no more than 30 % of the initial value.Implications. The developed methods were used in the preparation of a draft national standard of the Russian Federation “Steel engineering structures with fireproof coatings. Test methods for anticorrosion properties and resistance to climatic factors during operation” to ensure regulatory fire safety requirements for these structures.

Enhancing the Flame Retardancy of Polyester/Cotton Blend Fabrics Using Biobased Urea-Phytate Salt.

The use of biobased flame-retardant (FR) agents for reducing the flammability of polyester/cotton (T/C) blend fabrics is highly desirable. In this study, a novel and sustainable phosphorus/nitrogen-containing FR, namely, phytic acid-urea (PA-UR) salt, was synthesized. The PA-UR salt was further used to enhance the FR performance of T/C fabric through surface modification. We further explored the potential chemical structure of PA-UR and the surface morphology, thermal stability, heat release capacity, FR properties, and mode of action of the coated fabric. The coated fabric achieved self-extinguishing and exhibited an increased limiting oxygen index of 31.8%. Moreover, the coated T/C blend fabric demonstrated a significantly reduced heat release capacity, indicating a decreased fire hazard. Thermogravimetric analysis revealed the anticipated decomposition of the coated T/C blend fabric and a subsequent increase in thermal stability. The burned char residues also maintained their fiber shape structures, suggesting the presence of condensed FR actions in the PA-UR-coated T/C blend fabric.

Bio-based epoxy vitrimer with inherent excellent flame retardance and recyclability via molecular design

The development of biobased fire-safe thermosets with recyclability heralds the switch for a transition towards a circular economy. In this framework, we introduced a novel high-performance bio-epoxy vitrimer (named GVD), which was fabricated by forming a crosslinking network between bio-epoxy glycerol triglycidyl ether (Gte), varying amounts of reactive flame-retardant agent 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) (0–7 wt%) and a vanillin-based hardener (VA) with imine bonds. For instance, the epoxy vitrimer GVD5, featuring a DOPO content of 5 wt%, achieved a V-0 rating in the vertical burning test (UL-94) and obtained a limiting oxygen index (LOI) value of 31 %, surpassing the performance of pristine epoxy. Furthermore, the peak heat release rate and total heat release of GVD5 were reduced by 38.2 % and 26.3 %, respectively, compared to pristine epoxy. The GVD vitrimers further demonstrated exceptional reprocessability and recyclability, attributed to the presence of dynamic imine bonds within the topological crosslinking network. Remarkably, the epoxy vitrimers maintained the mechanical properties of the parent epoxy. Therefore, this work provides a facile strategy for fabricating high-performance and multi-functional bio-epoxy thermosets.

Synergistic flame retardancy and electrical conductivity in di-glycidyl ether of bisphenol-A epoxy composites with polyaniline and aluminum Tri-hydroxide

This study focuses on developing and characterizing multifunctional composites based on the diglycidyl ether of bisphenol-A (DGEBA) epoxy matrix. The aim is to enhance fire resistance and electrical conductivity properties for applications in various fields. To achieve this, aluminum tri-hydroxide (ATH) was incorporated as a flame retardant (FR) agent, while polyaniline (PANI) was added to impart electrical conductivity. The composites were categorized into three groups: the first containing flame retardant (FR), the second containing PANI for conductivity, and the third containing both PANI and FR for combined effects. E 60-FP emerged as the optimal multifunctional composite, exhibiting superior mechanical properties among the tested formulations. Thermogravimetric analysis (TGA) results provided valuable insights into the thermal stability of E 60-FP, revealing that it retained 42% of its initial mass at a temperature of 600 °C. Additionally, the composite achieved a V-0 rating in the UL 94 test, confirming its excellent fire resistance. Notably, E 60-FP displayed impressive mechanical strength, with a tensile strength of 7.2 MPa and a tensile modulus of 1117.6 MPa. Its flexural strength and modulus were measured at 31.2 MPa and 2800.2 MPa, respectively. Furthermore, the composite E 60-FP exhibited remarkable electrical conductivity, measuring 6.1 × 10–6 S cm−1. These findings highlight the potential of DGEBA epoxy composites containing PANI and ATH as promising materials for applications requiring fire resistance and electrical conductivity properties.

Guar-based aerogels with oriented lamellar structure and lightweight properties for flame-retardant and thermal insulation

In this study, a multi-functional guar gum aerogel with the oriented lamellar structure, which introduced sodium silicate (Na2O·nSiO2) and phytic acid (PA) as thermal insulation additives and flame-retardant agents, respectively, was fabricated via freeze drying. Our aerogel's chemical structure, morphology, and thermal and mechanical properties were analyzed. The oriented lamellar structure was attributed to the orientated growth of ice crystals, which was induced by the “silicate-guar, guar-phytate, and phytate-silicate” multiple hydrogen bonds formed between Na2O·nSiO2, PA, and guar gum. The density of the sample with 2 wt% PA could reach 0.0335 g·cm−3, and the porosity was 5 %, along with a specific pore volume of 0.8144 cm3·g−1. The mechanical properties and thermal insulation performed significant differences in the radial and axial direction of the oriented lamella (nearly 100 % resilience while 50 % deformation quantity and 0.0235 W/(m*K) of thermal conductivity in the radial direction, up to 0.079 MPa of compressive strength in the axial direction). The presence of PA attached a good flame-retardant ability to our aerogel (The Limiting Oxygen Index (LOI) was 30.77 %). This work provides a novel and promising method for developing anisotropic aerogel with excellent potential in building energy efficiency and flame-retardant.