Fire-retardant Materials Research Articles

Impact of additive manufacturing on reaction to fire

Additive manufacturing, including fused deposition modelling, is a growing technology opening up wide perspectives in material sciences. However, the ability to produce suitable fire-retarded materials via this process has never been studied extensively. This work focuses on understanding the relation between reaction to fire and numerous additive manufacturing parameters. The goal was to determine the impact of those parameters on standard fire tests such as flame propagation test (UL94V) and cone calorimetry. The results were compared with material samples formulated via usual processes. On one hand, flame propagation results are impacted by many additive manufacturing parameters, such as the design of the part and the material flow. On the other hand, cone calorimeter results are only influenced by parameters having an impact on the sample mass.

Simulation of nomograms showing the heating of steel structures with flame retardant coatings of different thicknesses (in the water)

Introduction. High temperatures cause deformation of steel structures which also lose stability and the bearing capacity, resulting in the collapse of structures with the subsequent collapse of the building. It is understood that intumescent paints are often used to increase the fire-resistance limits of steel structures up to R 90 and R 120. However the fire protection effectiveness of intumescent paints has not been sufficiently studied for the case of the long-term operation, and the application of this type of fire protection treatment of bearing steel structures requires justification. To ensure the building stability, coupled with the required fire resistance limit of structures, one should study the engineering factors affecting the fire resistance of steel structures that have intumescent paint coatings.Purpose of the research work. Development of approaches to simulation of nomograms demonstrating the heating of steel structures with flame retardant coatings of different thicknesses. The research work solved the following tasks:block diagrams of the research undertaking were developed to find the fundamental relationships between the dynamics of change in the structure of fire protection materials under thermal effects and the fire resistance limit of a building structure based on the choice of the functional criterion;mathematical models demonstrating dependence between the thickness of the dry layer of fire-retardant material were developed; the required fire resistance limit and thermo-physical characteristics of fire-resistant materials based on the experimental studies of the properties and effectiveness of fire-resistant materials were identified;nomograms showing dependences between the thickness of the dry layer of flame retardant materials and the flame retardant efficiency of flame retardants were made.Research methods. Hot Disk TPS 1500 thermal constant analyzer was used to analyze the thermo-physical characteristics of flame retardant materials. Thermal analysis was used to study the properties of flame retardants, as well as physical and chemical transformations occurring inside them under the programmed exposure to temperature effects and with the use of specialized thermal analysis equipment. The study of the fire protection efficiency for steel structures was conducted in accordance with GOST R (Russian State Standard) 53295–2009 “Fire protection means for steel structures. General requirements. The method of fire protection efficiency determination”.Results and their discussion. As a result of the research, an approach to prediction of the fire resistance of building structures was developed in the form of a research flowchart, used to choose the functional criteria. Experimental studies were conducted to identify mathematical dependences between the fire resistance and the indicators, which serve as functional criteria. In particular, when assessing the fire resistance of steel structures, a prediction is made on the basis of thermos-physical indicators. The authors were first to propose the introduction of the function of fire protection materials into the standard pattern of fire resistance analysis in the course of solving static and thermo-physical problems. The obtained data were used to make equations of dependence between the thickness of a dry layer of a fire-retardant material, the required fire-resistance limit of a structure, and the nomogram showing the heating of protected steel structures with fire-retardant coatings of various thicknesses.Conclusions. The results of the studies allowed identifying fundamental relationships between the dynamics of change in the structure of fire-retardant materials under the thermal effect and the fire resistance limit of a building structure on the basis of the choice of a functional criterion. Experimental studies of the properties and effectiveness of fire-resistant materials were conducted to develop a mathematical model showing dependence between the thickness of the dry layer of fire-resistant materials, the required fire-resistance limit and thermal-physical characteristics of fire-resistant materials.

New Polymer Composites with Aluminum Phosphates as Hybrid Flame Retardants.

Polymeric aluminum organophosphates are a class of nanostructured aluminum-based compounds that can be considered organic and inorganic hybrid materials. Aluminum phosphates have attracted considerable interest due to their ability to enhance composite materials' mechanical characteristics, lightweight, and thermal properties. Extensive studies have shown the potential of aluminum organophosphates as a component in the development of fire-retardant materials. Aluminum-organophosphorus hybrid (APH) materials have been prepared by reacting aluminum oxide hydroxide (boehmite) with alkyl and aryl phosphoric acids and used to prepare composites with epoxy resin. Boehmite is an aluminum oxide hydroxide (γ-AlO(OH)) mineral, a component of the aluminum ore bauxite. In this work, the composites based on epoxy resin Epidian 601 and commercial curing agent IDA were obtained. Pure boehmite and APH hybrids were added as flame retardants. FTIR and TGA analysis showed that obtained APH possesses a hybrid structure, high thermostability, and various morphologies. These new APH were incorporated into epoxy resin. The infrared spectroscopy confirmed the structure of hybrids and composites. Pyrolysis combustion flow calorimetry (PCFC) and cone calorimeter analyses were performed to assess the flame retardant properties of the composites. The results showed that the incorporation of 17 wt% APH allows a reduction of heat release rate but to a limited extent in comparison to pure boehmite, which is due to the different decomposition mechanisms of both boehmite and hybrids. The cone calorimetry test showed that residue contents correspond quite well to the mineral fraction from boehmite only. The hybrid APHs appear no more efficient than pure boehmite because the mineral fraction in APH is reduced while phosphate fraction cannot promote significant charring.

Weight Optimization of Plastic Injection Moulded Electrical Wire Casing Thermoplastic using Hybrid RSM-Tunicate Swarm Algorithm

The need for fire-retardant material for electrical wire covers and cases is increasing as the global population continues to expand at an alarming rate. In addition to having good fire and chemical resistance, CPVC (chlorinated polyvinyl chloride) is widely accessible in a assortment of forms and sizes, comprising rods, sheets, and tubes. Plastic injection moulding (PIM) provides a method that allows for the production of CPVC items at a rapid pace and at a low cost. When these mouldings are lightweight, they may reduce the amount of non-biodegradable materials that are used in their construction. The present research gives an insight into the CPVC material moulding for electrical wire casing elbows using an injection moulding machine, which was previously unexplored. Four plastic injection moulding parameters were considered in order to reduce the weight of the elbow, including injection pressure, mould closing speed, mould pressure, and backpressure. The 27 tests were piloted in line with Response Surface Methodbased Box-Behnken Design, and the factors were optimised using Tunicate Swarm Algorithm, which was recently developed. In the case of the plastic injection-moulded item, the analysis of variance revealed that the most significant parameter in the weight reduction was the material used. It has been determined that mould pressure is the most critical factor impacting the weight of the item when it is manufactured. As a result, the optimum manufacture of injection-moulded CPVC components will be facilitated, resulting in optimised weight while also minimising production time and raw material waste for electrical wire casing.

Development of elastomeric intumescent fire-retardant coating for protection of structures at sub-zero temperature condition

The aim of this work is to develop an elastomeric intumescent fire retardant (IFR) coating which can protect the substrates against fire after application and remain stable without any phase separation during storage at sub-zero temperatures. Initially, an elastomeric polymer solution (15 wt%) was prepared using a combination of solvents such as xylene, ethyl acetate and butanol. Thereafter, fire retardant materials along with some fillers such as TiO2 and kaolin were added to the prepared polymeric solution to make an IFR paint. Three different paint compositions were prepared by varying percentages of kaolin and TiO2 using a fixed PVC, and named as TK10, TK73 and TK11. The unpigmented polymeric solution was used as a control during the performance evaluation of the pigmented compositions. The effect of TiO2 and kaolin percentage on the prepared coatings was evaluated in terms of mechanical properties, thermal stability, fire retardancy and char stability characteristics using various analytical instruments. To simulate real conditions, the prepared coatings were also applied over the cotton cloth and fire protection ability was studied in detail. Results revealed that the kaolin and TiO2 combination increased the strength of the char and fire-resistant properties when used in the ratio of 7:3 i.e. TK73.

Properties of flame-retardant leaf fiber cement-based composites at high temperatures

Flame retardant modification of leaf fibers was carried out to solve the technical problem of poor fire resistance of plant fibers and improve the utilization rate of urban fallen leaves in building materials. The modification scheme adopts three flame retardants, i.e., ammonium polyphosphate (APP), magnesium hydroxide (MH), and aluminum hydroxide (ATH), and two covering layers, i.e., pure acrylic polymer lotion and water glass (Na2O · nSiO2) solution. The modified leaf fiber's combustion behavior and pyrolysis properties were tested and analyzed. The physical and mechanical characteristics, as well as the thermal insulation qualities, of leaf fiber cement-based composites (LFCC) were studied at high temperatures. The findings revealed that the three flame retardants had an effect on the chemical structure of leaf fibers. In comparison to leaf fibers without flame-retardant modification, flame-retardant-modified leaf fibers have a much greater thermal stability. and its LOI is greater than 27.0%, which is a fire-retardant material. Except for the sample with water glass as the modified cover layer, at high temperatures, the composite flame-retardant fiber LFCC's mass-loss rate is lower compared with fibers without flame-retardant modification or fibers modified with only one kind of flame-retardant. In the composite flame-retardant modified fiber LFCC, the samples with better strength at high temperature are those with ATH replacing 30% and 50% MH. The thermal conductivity of LFCC is negatively correlated with the range of temperature change.

Recent progress and multifunctional applications of fire-retardant epoxy resins

To improve the fire retardancy of epoxy resins, researchers use modifiers such as graphene, phosphorus, boron compounds or similar compatible fillers. The quantity of modifiers introduced to the epoxy matrix is crucial because high loading leads to deleterious thermal and mechanical properties. Taking that into account, this review identified the best epoxy-based fire-retardant polymer pertaining to modifier proportion. In this perspective, we classified fire-retardant epoxy resins into three groups: (1) intrinsic, (2) blends, and (3) composites. A closer investigation of the performance-enhanced material compositions based on multifunctional fire-retardant epoxy resins was undertaken. The reviewed key ingredient materials included ionic liquids, phosphorus, boron/boron nitride, aluminum hydroxide, silicone, lignin, graphene, carbon fibers, carbon nanotubes, and clay. Moreover, this review elucidated the multifunctional applications of fire-retardant epoxy resins, factors affecting fire retardancy, and current characterization techniques, including Underwriters Laboratories 94 testing, cone calorimeter, limiting oxygen index, SEM, and GC-FTIR. Finally, we outlined further research possibilities for smart and effective fire-retardant materials.

Environmentally Friendly Hybrid Organic-Inorganic Halogen-Free Coatings for Wood Fire-Retardant Applications.

Wood and wood-based products are extensively used in the building sector due to their interesting combination of properties. Fire safety and fire spread, however, are of utmost concern for the protection of buildings. Therefore, in timber structures, wood must be treated with fire-retardant materials in order to improve its reaction to fire. This article highlights the flame retardancy of novel hybrid organic-inorganic halogen-free coatings applied on plywood substrates. For this purpose, either a huntite-rich mineral (H5) or its modified nano-Mg (OH)2 type form (H5-m), acting as an inorganic (nano) filler, was functionalized with reactive oligomers (ROs) and incorporated into a waterborne polymeric matrix. A water-soluble polymer (P (SSNa-co-GMAx)), combining its hydrophilic nature with functional epoxide groups, was used as the reactive oligomer in order to enhance the compatibility between the filler and the matrix. Among various coating compositions, the system composed of 13% polymeric matrix, 73% H5 and 14% ROs, which provided the best coating quality and flame retardancy, was selected for the coating of plywood on a larger scale in one or two layers. The results indicated that the novel plywood coating systems with the addition of ecological coating formulations (WF-13, WF-14 and WF-15), prepared at two layers, reached Euroclass B according to EN13501-1, which is the best possible for fire systems applied to wood.

Fly Ash-Incorporated Polystyrene Nanofiber Membrane as a Fire-Retardant Material: Valorization of Discarded Materials.

Reusing or recycling waste into new useful materials is essential for environmental protection. Herein, we used discarded polystyrene (PS) and fly-ash (FA) particles and a fabricated fly-ash incorporated polystyrene fiber (FA/PS fiber) composite. The electrospinning process produced continuous PS fibers with a good distribution of FA particles. The prepared nanofibers were characterized by state-of-the-art techniques. The performances of the composite nanofibers were tested for fire-retardant applications. We observed that the incorporation of FA particles into the PS fibers led to an improvement in the performance of the composite as compared to the pristine PS fibers. This study showed an important strategy in using waste materials to produce functional nanofibers through an economical procedure. We believe that the strategy presented in this paper can be extended to other waste materials for obtaining nanofiber membranes for various environmental applications.

Characterization of Eggshell Composition at Different Size and Concentration in Fire-Retardant Application

This paper explores the thermal characterization of eggshell composition at different sizes and concentrations in glass-fiber-reinforced polymer (GFRP) composites as a potential flame retardants material. The eggshell powder (ESP) with different sizes (53 μm and 100 μm) and concentrations (10 wt% and 30 wt% ) was mixed with epoxy and laminated with four layers of 800 gsm E-glass. Thermo-gravimetric analysis (TGA) has been performed to analyze the thermal properties of the GFRP laminates. The finding reveals that incorporating the ESP in the GFRP composites material does not affect the epoxy matrix’s thermal properties as all the trails deteriorate between 450 °C to 480 °C. The combination of 100 μm filler size and 30 wt% ESP improved the fire resistance by 4.68% when compared to 53 μm size and 30 wt% ESP. In addition, the increment of filler loading from 10 wt% to 30 wt% of the 100 μm filler size showed an improvement of 10.9%. This concludes the potential of ESP as a fire retardant material.

Effects of High Temperatures on the Performance of Carbon Fiber Reinforced Polymer (CFRP) Composite Cables Protected with Fire-Retardant Materials.

In this study, the safe critical temperature that can be tolerated by CFRP tendons under normal working conditions was derived through tensile tests at room and high temperatures. Next, the times required to reach a safe critical temperature for CFRP cables protected with different types of fire-retardant materials of various thicknesses were determined through fire resistance tests, Finally, fitting the surface of the finite element simulation results allowed the establishment of the temperature rise calculation model of CFRP tendons under the protection of fire-retardant materials. The results showed that 300 °C can be regarded as the safe critical temperature. Both high-silica needled felt and ceramic fiber felt exhibited high fireproof performance. With an increase in the thickness of the fire-retardant material, the time for the CFRP tendon to reach the inflection point of the heating rate increased, and the safe fire resistance time increased exponentially. According to the HC temperature rise curve, the fire resistance time of CFRP tendons protected by 24 mm thick high-silica needled felt was 45 min, and that for CFRP tendons protected by 24 mm thick ceramic fiber felt was 39.5 min. Under the action of fire corresponding to the hydrocarbon temperature rise model, the safe fire resistance time of CFRP tendons protected by 45 mm high-silica needled felt or 50 mm ceramic fiber felt was more than 2 h, sufficient to meet the specification. The proposed model of fire resistance performance enables the determination of the thickness of the fire resistance material required to obtain different degrees of fire resistance for CFRP cables for structural use.

Investigation of Flame Retardancy Effect of Licorice Root Extract on Cotton and Cotton-Polyester Blended Fabrics

In this study; licorice root, which is a sustainable natural material with a low environmental waste load, is used as an alternative fire retardant (FR) material. Flammable retardancy properties of 100% cotton and 50% cotton-50% polyester blended woven fabrics were researched by using licorice root and commercial organic phosphorus-nitrogen and phosphorus including compounds. Flame retardancy and thermal decay behaviour of the cotton and cotton/polyester blended fabric samples were qualified by the vertical burning test, limiting oxygen index (LOI), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). The findings revealed that licorice root extracts enhanced the thermal behavior of the cotton and cotton/polyester blended fabrics after padding and coating processes. The practices increased the amount of oxygen demand for combustion in the environment and besides they did not change the morphological properties of the fabric samples. As a result, the usage of licorice root extracts considerably improved the fabric’s flammability under test.

Polydopamine primed phosphorylated sepiolite-polypropylene nanocomposite with enhanced thermal, rheological, and flame retardant properties

Phosphorous-based fire-retardant materials are considered eco-friendly and can be reinforced in polymers or functionalized on the polymer backbone to reduce combustibility. Herein, sepiolite fiber (Spl) was first primed with polydopamine (PDA), and the amine group density was increased by Michael's addition of EDA to further graft H3PO3. The stepwise modifications and formation of the phosphorylated Spl-PDA-P and Spl-PDA-EDA-P were established by analyzing surface chemical structure, surface and internal morphology, and surface area. Further, the Spl-based fillers were reinforced in the PP matrix, and the nanocomposites were systematically characterized for thermal stability, mechanical property, flow behavior, and fire-retardant properties. The PP_Spl-PDA-EDA-P nanocomposite at 5% filler loading has a tensile and flexural strength of 36.3 MPa and 50.6 MPa, respectively. The flow property was established by determining melt flow index (MFI) of 13.3 ± 0.75 g/10 min and melt rheological properties. After phosphorylation, the Spl-based fillers have shown shear thinning behavior with increased filler loading. Finally, the prepared nanocomposites were evaluated for fire retardant properties by determining the limiting oxygen index (LOI) and UL-94 vertical burning test. The neat PP has an LOI of 17.5, and a maximum improvement was observed in the case of PP_Spl-PDA-EDA-P with an LOI of 30.2. Overall, the grafting of H3PO3 on PDA coated Spl has created a robust filler to impart fire-retardant property in combustible PP.

Effect of Different Pre-Treatment on the Microstructure and Intumescent Properties of Rice Husk Ash-Based Geopolymer Hybrid Coating.

Despite the growing popularity of rice husk ash (RHA) in various applications, limited research has been devoted to identify the influence of silica content in RHA on the intumescent properties. The present work aims to introduce a novel and economical geopolymer hybrid fire retardant coating by utilizing the use of RHA. The silica from Rice husk (RH) was extracted using distilled water and hydrochloric acid as leaching agents and subjected to pyrolysis treatment. X-ray fluorescence (XRF) analysis indicated that RH that underwent HCl pre-treatment at 600 °C for one hour produced a high purity amorphous silica content of 93.92%. XRD measurements revealed that HCl pretreatment increased the crystallization temperature of RHA to 1000 °C and retained the amorphous state of silica for 2 h. In a fire resistance test, temperature at the equilibrium and time taken to reach 200 °C for sample S3 (93.92% wt. silica) showed 5.83% and 3.48% improvement compared to sample S1 (87.49% wt. silica). The microstructure analysis showed that sample S1 possessed bigger pores on the coating surface while an increment in silica content in sample S3 produced a dense foam structure. Results from a fire resistance test were supported by the Energy dispersive X-ray (EDX) analysis of the sample. The oxygen-to-carbon ratio of S1 and S3 coating samples were 1.695 and 1.622 respectively, which indicated that lower oxygen–to-carbon ratio in sample S3 coating resulted in better anti-oxidant properties. Interestingly, the increment of SiO2 content in RHA efficiently improved the compactness of the char layer, which resulted in a relatively higher fire-retardant efficiency. RHA proved to be a promising environmentally friendly strategy to replace halogenated fire retardant materials.

Polyimide Copolymers and Nanocomposites: A Review of the Synergistic Effects of the Constituents on the Fire-Retardancy Behavior

Carbon-based polymer can catch fire when used as cathode material in batteries and supercapacitors, due to short circuiting. Polyimide is known to exhibit flame retardancy by forming char layer in condensed phase. The high char yield of polyimide is attributed to its aromatic nature and the existence of a donor–acceptor complex in its backbone. Fabrication of hybrid polyimide material can provide better protection against fire based on multiple fire-retardancy mechanisms. Nanocomposites generally show a significant enhancement in mechanical, electrical, and thermal properties. Nanoparticles, such as graphene and carbon nanotubes, can enhance flame retardancy in condensed phase by forming a dense char layer. Silicone-based materials can also provide fire retardancy in condensed phase by a similar mechanism as polyimide. However, some inorganic fire retardants, such as phosphazene, can enhance flame retardancy in gaseous phase by releasing flame inhibiting radicals. The flame inhibiting radicals generated by phosphazene are released into the gaseous phase during combustion. A hybrid system constituted of polyimide, silicone-based additives, and phosphazene would provide significant improvement in flame retardancy in both the condensed phase and gas phase. In this review, several flame-retardant polyimide-based systems are described. This review which focuses on the various combinations of polyimide and other candidate fire-retardant materials would shed light on the nature of an effective multifunctional flame-retardant hybrid materials.

Circular economy implementation in the development of fire-retardant materials used in construction, industry, and general-purpose products

During a fire, passive fire protection systems are designed to prevent the spread of flames, smoke, and toxic gases. The new fire-retardant (FR) material, used for passive fire protection, is created by combining copolymers (VC–co–VAc) (Slovinyl KV 173) and PVC K70 with expanded graphite and plasticizers/modifiers such as diisononyl phthalate - DINP, diisononyl terephthalate - DINTP, dioctyl adipate - DOA, as well as plasticizers that are synthesized based on tertiary recycling of waste poly(ethylene terephthalate) (PET), 1-hexadecene, azodicarbonamide (ADC), tri(p-cresyl phosphate), epoxidized soybean oil (ESO) and acrylate emulsion (DH50, Ecrylic, or Flexryl, etc.). The obtained material's morphology was examined using an emission scanning electron microscope (FESEM) field. Tensile testing was used to determine the mechanical properties of the obtained samples, as well as Shore A hardness and toughness using the Charpy impact test. All samples obtained were tested according to non-flammability standards. To conform to the new trend of "green economy," the development of novel eco-friendly FRs with improved thermal and mechanical properties will include careful consideration of environmental protection and sustainable development.

Review of preventive and constructive measures for coal mine explosions: An Indian perspective

Firedamp and coal dust explosion constitute a lion’s share in mine accidents in a global mining scenario. This paper reports a list of mine explosion disasters since last two decades, a critical review of the different prevention and constructive measures, and its recent development to avoid firedamp and coal dust explosion. Preventive legislation in core coal-producing countries, viz. China, USA, Australia, South Africa, and India related to firedamp and coal dust explosion are critically analysed. Accidents occurred due to explosion after Nationalisation of Coal Mines (1973) in India are listed. Prevention and constructive measures adopted in India are critically analysed with respect to the global mining scenario. Measures like methane credit concept, classification of mines/seams with respect to explosion risk zone, deflagration index; installation of automatic fire warning devices, canopy air curtain technology, explosion-prevention measures, such as fire-retardant materials, inhibitors, extinguishing agent, dust suppressor, and active explosion barrier are discussed in detail to avoid explosion and thereby adhering to zero accident policy due to coal mine explosion.

Structure, Property, Processing and Applications of Fire Retardant Materials: A Brief Review

Fire though an important component of life, the devastating effect of fire accidents is a threat to life and materials. Thus, the prevention and control of fire are becoming a serious concern. Hence, it is no wonder that fire retardant materials (FRMs) are slowly becoming ubiquitous in our daily lives. To control the fire in an unexpected fire accident or to prevent fire accidents FRMs are becoming essential requirements. To save material or life, fire retardant materials have been used for long knowingly or unknowingly. However, the understandings of chemistry and thermochemistry of materials helped for the development of efficient FRMs. Diversified materials, processing methods, and application modes have been developed, and all of them become specific depending on the nature and origin of the fire. In this regard, the inorganic FRMs form a distinct category due to their low cost, easier processing and wider choice of application mode without leaving any additional environmental burden either to land or the atmosphere. In this paper, different fire retardant materials and their properties with the abilities to tackle the fire at different temperatures are reviewed. The primary characteristics of fire and the thermal behaviours of FRMs as well as changes in behaviour/properties when FRMs are treated with certain synergistic systems are discussed. The importance of composition, morphology and structure of FRMs on the efficiency and applicability are discussed. Recent developments on the synthesis and characterisation of different types of FRMs and their composites have been elaborated. The effective applications and the commercial products based on their properties are also briefly covered. Overall, the review provides an overview of existing information on fire retardant materials in terms of their synthesis, processing, usability and limitations, with a prime attention on the process-structure-property relations of these materials.

Potential of Commercial Wood-Based Materials as PCB Substrate.

In our research on sustainable solutions for printed electronics, we are moving towards renewable materials in applications, which can be very challenging from the performance perspective, such as printed circuit boards (PCB). In this article, we examine the potential suitability of wood-based materials, such as cardboard and veneer, as substrate materials for biodegradable solutions instead of the commonly used glass-fiber reinforced epoxy. Our substrate materials were coated with fire retardant materials for improved fire resistance and screen printed with conductive silver ink. The print quality, electrical conductivity, fire performance and biodegradation were evaluated. It was concluded that if the PCB application allows manufacturing using screen printing instead of an etching process, there is the potential for these materials to act as substrates in, e.g., environmental analytics applications.

Fabrication of fire-retardant building materials via a hyper-crosslinking chemical conversion process from waste polystyrenes

• Waste PS was used for the preparation of fire-retardant building materials. • Hypercross-linking reaction induced high value-added use of waste PS. • The preparation process can be facilely scaled up. Polystyrene (PS) is rich in plastic materials, but it produces a large amount of waste every year, causing a huge burden on the environment. Although PS plastic is the source of a common "white pollution" in daily life, it still has a high utilization value. At the same time, the flammability of PS material determines that it cannot be applicated in places where fire accidents occur frequently. As a result, its application has been greatly limited. In order to realize the efficient utilization of waste PS and broaden its scope of application, PS was modified by hyper-crosslinking in order to improve its fire-retardant performance. In this method, the PS solution with high purity was obtained by dissolving waste PS foam with 1,2-dichloroethane (DCE), and then the hyper-crosslinked polymer with high specific surface area was prepared by adding cross-linking agent formaldehyde dimethyl acetal (FDA) and a Lewis-acid catalyst ferric chloride (FeCl 3 ). Further studies showed that the effects of the amount of cross-linking agent FDA, catalyst FeCl 3 and PS on the reaction products were different. In addition, compared the as-prepared fire-retardant materials with PS foam from the aspects of flame retardancy and thermal insulation, it can be concluded that the fire-retardant performance of the materials prepared by this method has been significantly enhanced. And it is proved that this method is feasible towards the preparation of a large number of fire-retardant composite materials by using a scale-up experiment.