Cone Calorimeter Test Research Articles

Novel rich aromatic and phosphorus-containing compound cured epoxy resins toward outstanding comprehensive performances

Epoxy resin (EP) is quite flammable, which limits its application in areas such as coatings and electronic and electrical materials. In this study, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) (or diphenylphosphine oxide (DPO)) 3-cyclohexene-1-formaldehyde (CC) and 4,4’diaminodiphenylmethane (DDM) were selected for the synthesis of two rich aromatic and phosphorus-containing compounds (DOPO-CC and DPO-CC). DOPO-CC and DPO-CC were introduced into epoxy pre-polymers to prepare epoxy thermosets with flame retardancy. When 5 wt% DOPO-CC (P content of 0.50 wt%) or DPO-CC (P content of 0.52 wt%) was added, the LOI values of the epoxy thermosets increased from 25.5% (pure EP) to 33.5% (EP added DOPO-CC) and 31.0% (EP added DPO-CC), respectively, and these epoxy thermosets also achieved the UL-94 V-0 rating. Additionally, cone calorimeter tests showed that the peak heat release rate (PHRR) and total heat release (THR) of epoxy thermoset containing 5 wt% DPO-CC reduced by 42.0% and 39.7% compared to those of pure EP, respectively. By reducing the thermal degradation rate (condensed phase) and combining and quenching free radicals (gaseous phase), the introduction of DOPO-CC or DPO-CC can efficiently improve the flame retardancy of epoxy thermosets. More importantly, the epoxy thermosets containing DOPO-CC or DPO-CC exhibited better mechanical properties than pure EP, which could be proven by the storage modulus and tensile strength. This study provided a new class of rich aromatic and phosphorus-containing compounds that can serve as co-curing agents for epoxy thermosets with outstanding comprehensive performances.

Flame retardance of a bio-based furan resin: Effects of added flame retardants

A study of the flammability of a biobased furan resin via limiting oxygen index and UL-94 has shown its inherent flame retardant properties. In a cone calorimetric test at 50 kW/m2 external irradiance, however, it ignited within 50 s and burnt, producing 489 kW/m2 peak heat release and 24 MJ/m2 total heat release but minimal smoke production. The flame retardance of the furan resin was further improved by the addition of the phosphorus-containing inorganic flame retardants, ammonium polyphosphate (APP) and melamine polyphosphate (MPP), and their well known condensed phase activity was further supported by thermogravimetric analysis (TGA). The organic flame retardants, resorcinol bis(diphenyl phosphate) (RDP) and bisphenol-A bis(diphenyl phosphate) (BAPP) had no effect on flame retardance, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) had only minimal effects in LOI and cone calorimetric tests, which was at variance to the results of TGA tests. This disconnect between the tests involving flaming combustion (LOI and cone calorimetry) and slow controlled heating (TGA) was attributed to the low flash points and high boiling points of the organic flame retardants, respectively.

Bio-Based Alkali Lignin Cooperative Systems for Improving the Flame Retardant and Mechanical Properties of Rigid Polyurethane Foam.

Lignin was utilized as an environmentally friendly synergistic agent to augment the fire resistance and mechanical characteristics of rigid polyurethane foam (PUF)/melamine-formaldehyde resin ammonium polyphosphate (MFAPP). The incorporation of lignin significantly enhanced the charring capability and flame retardancy of PUF/MFAPP. Specifically, PUF/MFAPP12/A-lignin3 exhibited a charring residue of 23.1% at 800 °C, accompanied by an increase in the limiting oxygen index (LOI) to 23.1%, resulting in a UL-94 V-0 rating. The cone calorimeter test (CCT) revealed that the peak heat release rate (PHRR), total heat release (THR), smoke production rate (SPR), and total smoke production (TSP) values of PUF/MFAPP12/A-lignin3 were all lower than for pure PUF. MFAPP and alkali lignin exerted a noticeable influence on the physical and mechanical properties, leading to increases in density (35.4 kg/m3), thermal conductivity (32.68 mW/(m·K)), and compressive strength (160.5 kPa). Observations of the morphology and elemental composition of char residues after combustion indicated the formation of an intact, thick, and continuous char layer enriched with nitrogen and phosphorus elements, which acted as a protective shield for the underlying foam.

Influence of char‐forming lignin in combination with aluminium phosphinate on thermal stability and combustion properties of polyamide 11 blends

AbstractPolyamide 11 (PA) blends based on char‐forming industrial lignin and aluminum phosphinate (AlP) were prepared to improve flame retardant (FR) properties using a green and eco‐friendly approach. This study investigates the thermal degradation and combustion behavior of PA blends prepared by using AlP in combination with two different types of industrial lignins (i.e., kraft lignin (DL) and lignosulphonate lignin (LL). Thermogravimetric (TG) analysis showed that ternary blends containing LL and AlP developed higher char residue up to 10.7 wt% upon decomposition in inert atmospheres. The combination of lignin and AlP increases the thermal stability by shifting the initial decomposition temperature (T5%) and temperature at maximum decomposition (Tmax) to a higher temperature range, attributed to the stabilization of decomposition products. Furthermore, combustion behavior studied by cone calorimeter (forced combustion) and pyrolysis combustion flow calorimeter (PCFC) tests presented a significant reduction in the peak of heat release rate (PHRR) and total heat release (THR). It was found that LL and AlP‐containing blends more effectively decreased fire parameters like PHRR and THR than that of DL and AlP‐containing blends. The best interaction with reduced fire‐retardant properties was obtained when 10 wt% loading of lignin (DL/LL) and AlP was used. The reduction in heat release parameters was mainly ascribed to the condensed phase mechanism by forming an efficient protective char layer, which acts as a barrier against heat and mass transfer between the condensed and the gas phases. Raman spectroscopy analysis also confirmed the formation of the protective graphitic layer in the condensed phase.

Fire performance, toxicity, and thermal diffusivity of wastepaper mixed with magnesium hydroxide, depending on the particle size of expandable graphite

As the construction of high-rise buildings increases to solve residential spaces caused by high density population concentration, the occurrence of fire accidents in high-rise buildings is also increasing. The primary cause of fire damage in high-rise buildings is the spread of fire caused by exterior wall finishes. Therefore, it is essential to develop semi-non-combustible finishes that can be applied to high-rise buildings to prevent the spread of fire due to exterior wall finishes. To address this issue, numerous studies are being conducted to develop flame retardant finishing materials that reduce heat release rate and total heat release. A double flame retardant mixed waste paper with expandable graphite and magnesium hydroxide was manufactured to improve the fire performance of cellulose building finishing materials. Total heat release (THR), CO, and CO2 Generation changes were measured using a cone calorimeter, and thermal diffusion rate was measured through the LFA 1000 experiment. The correlation of total heat release, CO generation, CO2 generation, and mass reduction rate by variation of expandable graphite's mesh size at double flame-retardant waste paper were secured through a cone calorimeter test. The thermal diffusion rate data of the specimen were secured through the LFA 1000 experiment. Through experiments, it has been confirmed that specimens using specific expandable graphite particles can be utilized as fire-resistant finishing materials in construction, ensuring fire resistance performance.

Construction of Ag-mediated organic-inorganic phosphorus-hybrid coating for flame-retardant and antibacterial cotton fabrics

Cotton fabrics (CF) with high flame retardancy and antibacterial performance are attracting more and more attention in the practical applications, e.g. home decorations. In this work, a novel Ag-mediated organic-inorganic phosphorus-hybrid coating (5BL/Ag-D) was developed using polyethylene imine (PEI)/ammonium polyphosphate (APP) polyelectrolyte bilayer and Ag-phosphoryl triazole complex (AgD) via dip-coating method for flame-retardant CF with the antibacterial property. Interestingly, limiting oxygen index (LOI) of CF/5BL/Ag-D was sharply promoted to 33.5 % from 18.6 % of CF. Besides, CF/5BL/Ag-D could self-extinguish in the vertical burning test with afterflame time and afterglow time as low as 0 s. More importantly, as revealed in the cone calorimeter tests (CCT), the heat release involving peak heat release rate (PHRR) and total heat release (THR) of CF/5BL/Ag-D decreased from 193.8 kW/m2 and 14.8 MJ/m2 of CF to merely 16.7 kW/m2 and 3.2 MJ/m2, respectively. In addition, owing to the presence of Ag+, CF/5BL/Ag-D was endowed with the desired antibacterial property, and the bacteriostatic rates of CF/5BL/Ag-D on escherichia coli (E. coli) and staphylococcus aureus (S. aureus) were up to 94.7 % and 95.1 %, respectively. Moreover, the softness, the whiteness and the mechanical properties of CF/5BL/Ag-D were comparable to those of CF. In general, this work provides a promising approach to prepare Ag-mediated organic-inorganic phosphorus-hybrid coating for multifunctional cotton fabrics.

Effect of flame‐retardant melamine and dispersants on the mechanical, thermal, and foaming properties of flexible polyurethane foam

AbstractThe objective of this study was to investigate the effect of adding flame‐retardant melamine and five different dispersants on the precipitation, foaming, mechanical, and thermal properties of flexible polyurethane foam (FPUF). Precipitation experiments were conducted to analyze the effect of dispersant on the separation of flame retardant and polyol, and the foaming characteristics of polyurethane (PU) foam after adding dispersant were analyzed. The effect of adding a dispersant on mechanical strength was characterized by measuring tensile strength, tearing strength, and hardness, and scanning electron microscopy analysis was performed to analyze morphological characteristics. Thermogravimetric analysis (TGA) was performed to analyze the thermal properties of PU foam. A horizontal flame test, limiting oxygen index test, and cone calorimeter tests were conducted to examine the flame retardancy of PU foam with flame retardant melamine and dispersant added. The dispersant ANTI‐TERRA‐U is a solution of a salt of unsaturated polyamine amides and low‐molecular acidic polyesters. And, the dispersant BYK‐220S is a solution of a low molecular weight, unsaturated acidic polycarboxylic acid polyester with a polysiloxane copolymer. The dispersants ANTI‐TERRA‐U and BYK‐220S improved the density, tensile strength, tear strength, and hardness of FPUF. TGA of the top and bottom portions of the foam showed less weight difference for samples containing dispersants, indicating better homogeneity due to improved dispersibility. Therefore, we conclude that dispersants are beneficial additives to improve the mechanical properties and dispersibility of PU foam.

Facile preparation of high-performance plywood adhesive from gelatinized corn starch crosslinked with ammonium dihydrogen phosphate

A flame retardant high-performance gelatinized starch (GS)-ammonium dihydrogen phosphate (ADP) wood adhesive, named GS-ADP adhesive was prepared by condensation of GS and ADP under acidic condition. The preparation process of GS-ADP adhesive is very simple by mixing and stirring GS and ADP evenly at room temperature. The results revealed that the GS-ADP adhesive has good storage stability and water resistance, and its wet shear strength is much higher than that of phenolic resin (PF) adhesive. Markedly, the cone calorimeter test results show that G-ADP adhesive has good flame retardancy, and the plywood based on GS-ADP adhesive has good flame retardancy. Meanwhile, it can be seen from dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) that GS-ADP has excellent modulus of elasticity (MOE), high glass transition temperature (Tg) and good thermal stability. The findings suggest that GS-ADP could be a viable substitute for PF resin in structural wood fabrication.

Ionic liquids modified MXene as a flame retardant synergist for the unsaturated polyester resin

AbstractI‐MXene with excellent dispersibility was successfully prepared using the chemical grafting method with 1‐butyl‐3‐methylimidazole hexafluorophosphate ([BMIM]PF6) onto MXene. It was characterized by X‐ray diffraction (XRD) and transmission electron microscopy (TEM), which was added to unsaturated polyester resin (UPR) as a synergistic agent, combined with ammonium polyphosphate (APP) to improve the flame retardancy of composites. Tensile strength of the composites was measured using the electronic universal material testing machine. The results showed that the incorporation of I‐MXene was able to increase the tensile strength and elongation at break of the composites. The flame retardancy and thermal stability of the composites were investigated through limiting oxygen index (LOI), cone calorimeter test (CCT), TG and Fourier‐infrared spectroscopy (FT‐IR). The experimental data showed that the LOI values of I‐MXene/APP/UPR composites increased to 29.1%, complying with UL‐94V‐0 rating. Its peak heat release rate (pHRR) and total heat release (THR) were 19.35% and 16.35% lower than those of APP/UPR composites, and the total smoke production (TSP) was reduced by 10.78%. When heated to 800°C, the amount of residual carbon increased by 7.71%. The catalytic effect of I‐MXene contributed to the formation of a compact and expanded carbon layer, resulting in further suppression of heat and smoke release.Highlights A new type of modified MXene is obtained. It has good dispersivity and synergistic effects. It has good flame retardancy and smoke suppression effects.

Preparation of DOPO coated conjugated microporous polymer hollow nanospheres with excellent flame retardancy and thermal insulation

Materials with thermal insulation and flame retardant properties are highly sought after in construction industry. In this study, two hollow-structured conjugated microporous polymer spheres (HCMPs) were successfully synthesized via the template method by polymerizing 1,3,5-triethynylbenzene with 3-amino-2,6-dibromopyridine and 2-amino-3,5-dibromopyridine respectively. To enhance flame retardant properties, HCMPs were impregnated with ethanol-soluble 6 H-dibenzo (C, E) (1,2) phosphine oxide-6-oxide (DOPO) (named as HCMP-FR), which maintains a hollow structure, enabling it to serve as a heat insulator, as observed under transmission electron microscope (TEM). The two types of HCMP-FR with a thermal conductivity of 0.047 W m−1 K−1 and 0.051 W m−1 K−1 respectively, exhibit excellent thermal insulation property. HCMP-FRs were added in to epoxy resin (EP) composites to further investigate the property of it. Under addition of 1.3%wt HCMP1-FR and HCMP2-FR, the thermal conductivity of EP composites (0.159 W m−1 K−1 and 0.146 W m−1 K−1) decreased by 25.3% and 31.4% compared with pure EP composites respectively, and the density (0.651 g cm−3 and 0.8 g cm−3) decreased by 42.1% and 22.5%, significantly reducing EP's thermal conductivity and density. The cone calorimeter (CC) tests show that the pHRR of EP composites at 0.6%wt addition was 859.04 kW m−2 and 904.35 kW m−2, respectively, which were 17.5% and 13.1% lower than that of pure EP, and the TSP decreased by 44.9% and 41.3% when 1.3% HCMP-FRs was added, which shows an excellent smoke depressing property. Therefore, the HCMP-FRs synthesized have highly promising for application in thermal insulation and flame retardancy of energy saving building.

Enhancing the thermal stability and fire retardancy of bio-based building materials through pre-biochar system

In an environment that emphasizes ecological sustainability, there is increasing interest in the development of bio-building materials to achieve carbon neutrality. Among bio-building materials, plant-based materials must also consider improving fire resistance. In this study, we developed composite materials with improved fire resistance by adding 0 %, 5 %, and 10 % biochar to bio-materials. A clear improvement in fire resistance was observed in the composite material (CB10) added with 10 % biochar. Through TGA analysis, thermal stability was improved by about 27.6 %, and through cone calorimeter testing, it was confirmed that the peak heat release rate was reduced by 34.5 %. The time to reach the maximum value was also delayed from 25 s to 45 s. This study confirmed that biochar is an eco-friendly fire retardancy that acts as a barrier against heat and oxygen, and that bio-materials can also stably improve fire resistance.

A tryptamine-based DOPO derivative as a flame retardant for epoxy resins

A reactive flame retardant (HLD) is prepared for epoxy (EP) resin using tryptamine (PTM), 9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide (DOPO), and vanillin (VN) as reaction monomers. The effects of HLD on the thermal stability, mechanical characteristics, and flame resistance of the EP are evaluated. When 7 wt.% of HLD (only 0.43 wt.% of phosphorus) is added to pure EP, the thermal breakdown rate of the resulting EP/HLD7 composite is lowered by 28 %, and its coke output at 700 °C is raised by 45 %. In the cone calorimeter test (CCT), the peak heat release rate (PHRR), total heat release (THR), total smoke production (TSP), and average effective thermal combustion (av-EHC) of the EP/HLD7 decrease by 52.1 %, 24.8 %, 25.1 %, and 34.0 %, respectively, compared to those of pure EP. A high limited oxygen index (31.86 %) and a V-0 rating in the UL-94 test are also achieved for EP/HLD7. The flame-retardancy mechanism is studied using thermogravimetric analysis/infrared spectroscopy (TG-IR) and scanning electron microscopy (SEM). The quenching effect of phosphorus-containing radicals, the dilution effect of noncombustible gases, and the impeding effect of the carbon layer in the condensed phase contributed collectively to the excellent flame-retardancy of EP/HLD7.

Zinc hydroxystannate coated by polyphosphazene to improve the fire safety and suppress the smoke of epoxy resin

A novel flame retardant containing zinc, tin, phosphorus and nitrogen elements is synthesized from 4,4-Diaminodiphenyl ether (ODA), Phosphonitrilic chloride trimer (HCCP), Triethylamine (TEA) and 1,4-Dioxane by polycondensation reaction. Herein, a hollow, encapsulated material (hollow zinc hydroxystannate@polyphosphazene, H-ZHS@PZS) is introduced as a flame retardant into epoxy resin (EP). And the hollow structure can delay the release of decomposition products and the diffusion of heat. Thermogravimetric analysis (TGA) shows that the EP has good thermal stability after adding H-ZHS@PZS, and the material weight loss of 5 % corresponds to a minimum temperature of 328.4 °C, and the residual carbon mass increases by 77.7 % compared to the pure EP. The well-designed H-ZHS@PZS has good flame retardancy. Cone calorimeter tests (CCT) show that introducing 5 % H-ZHS@PZS into the EP reduces the peak of heat release rate, total heat release, total smoke production, and peak CO production rate by 55.4 %, 19.7 %, 22.5 %, and 59.3 %, respectively. Benefiting from a well-formed nanosheet-polymer interfaces, the mechanical performance is improved. It is worth noting that the improved flame retardancy of EP is mainly assigned to the physical blocking of H-ZHS and the structure of PZS promotes the formation of a dense and continuous char in the condensed phase.

Analysis of the pyrolysis process of ionic liquid-based flame retardant rigid polyurethane foam

In this study, flame retardant polyurethane rigid foam was prepared by incorporating 15 wt% ammonium polyphosphate (APP) and ionic liquid (1-butyl-2,3-dimethylimidazolium tetrafluoroborate, abbreviated as B4F). The flame retardant and thermal stability of the material were evaluated using vertical combustion (UL-94), limiting oxygen index (LOI), cone calorimeter (CONE), and thermogravimetric analyzer (TG) tests. Additionally, scanning electron microscopy (SEM), Raman spectroscopy (Raman), and X-ray photoelectron spectroscopy (XPS) were utilized to explore the flame retardancy mechanism in the carbon layer after combustion. The experimental results showed that the addition of 1 wt%B4F and 14 wt% APP to the polyurethane (RPUF/14APP/1B4F) significantly improved the vertical combustion test, upgrading it from the V-1 level to the V-0 level. This improvement was attributed to the increased degree of graphitization of the material, as evidenced by the reduced ratio of amorphous carbon to graphitic carbon (ID/IG) from 2.68 to 1.38. XPS analysis revealed that RPUF/14APP/1B4F exhibited a higher C/O ratio in the residual carbon (3.03) compared to RPUF/15APP (1.84), indicating that B4F effectively enhanced the antioxidant properties of the flame-retardant materials. Under the air atmosphere, RPUF/14APP/1B4F demonstrated an increased char formation at 800 °C (21.24 %), which was 71.01 % higher than RPUF/15APP. The interaction between B4F and APP led to the formation of a more stable char layer structure in polyurethane, further enhancing its flame retardancy. In conclusion, the RPUF/14APP/1B4F demonstrated a synergistic flame retardancy effect and enhanced thermal stability. The addition of B4F improved the graphitization degree of the material and increased the C/O ratio in the residual carbon, enhancing the antioxidant properties of the system. Moreover, the interaction between B4F and APP promoted the formation of a more stable char layer, effectively improving the flame retardant properties of the polyurethane. These findings provide valuable insights for the development of advanced flame retardant polyurethane materials with improved fire safety in various applications.

Flame‐retardant composite derived from polyurethane/wood‐fiber

AbstractWood–plastic composites (WPCs) are facing fire hazard when they are used in construction and furniture and need to be treated with fire protection. In this work, polyurethane (PU) was applied to derive simultaneously flame‐retardancy‐improved and mechanically strengthened wood‐polyurethane composites (WPUCs). It was constructed with ammonium polyphosphate (APP) and PU by a simple way. The results showed that a decrease in smoke production in the Cone Calorimeter Test was measured. When the mass of APP is 18% of PU, limiting oxygen index can reach 31.2%. In the combustion test, the peak of heat release rate and total smoke production for WPUCs were, respectively, decreased by 42.1% and 89.7% in the presence of the above ratio of APP and PU. In addition, the results of the functional group test show that PU contains highly reactive ‐NCO which is bonded to the ‐OH and moisture in the wood fiber, resulting in improvement of physical and mechanical properties. The mechanism for the flame retardancy of WPUCs revealed that polyphosphoric acid produced by APP pyrolysis catalyzed PU into the char, and PU was arched by the resulting gases such as NH3 to form the tiny spherical structure, which worked in blocking heat and the exchange of substances. WPUCs with APP prepared by this method are shown to have improved results, and, therefore, it is expected to provide a new strategy for the preparation of flame‐retardant WPCs.

Synthesis, characterization and performance evaluation of a flame retardant plasticizer for poly(vinyl chloride) derived from biobased vanillic acid

The utilization of biobased resources presents a novel approach for the development of high-performance plasticizers with exceptional flexibility. Nevertheless, the combustibility of flexible poly(vinyl chloride) (PVC) products containing high content plasticizers is frequently disregarded. The development of PVC functional plasticizers requires careful consideration of a good balance between flame retardancy, migration resistance and plasticity through molecular structure design. Currently there is a dearth of biobased plasticizers that exhibit exceptional comprehensive properties. Therefore, a novel biobased flame-retardant plasticizer (VA8-P) has been synthesized from vanillic acid and fully characterized using NMR, IR and MS. The VA8-P plasticized PVC exhibits a lower glass transition temperature and higher low temperature resistance, while its elongation at break is 1141.6% higher than unmodified PVC. Transmittance, haze, cross-sectional SEM and 2D/3D AFM all demonstrate its good optical properties and the compatibility of the plasticizer with polymer matrix. PVC plasticized using VA8-P exhibits better hydrophilicity and especially superior migration resistance than does the same polymer plasticized using DOP. The thermal stability and char residue rate for decomposition of VA8-P plasticized PVC are better than the same parameter of material plasticized with DOP. In cone calorimeter tests, VA8-P plasticized PVC showed excellent heat barrier effect. Additionally, PVC-P3 reached the UL-94 VTM-0 level in the vertical burning test. Its flame-retardant mode of action was also verified by TGA–FTIR analysis. A functional biobased plasticizer with excellent comprehensive properties has been synthesized. This material exhibits greater flexibility than many traditional flame-retardant additives and its use can be expected to improve the fire resistance of flexible PVC.

A new approach to prepare flame retardant epoxy resin with excellent transmittance, mechanical properties, and anti-aging performance by the incorporation of DOPO derivative

Aiming to develop high performance flame-retardant epoxy resin (EP), a novel phosphorus-containing flame retardant named 6-(3-(2-hydroxyphenyl)propyl)dibenzo-[1,2]oxaphosphinine 6-oxide (HP-DOPO) was synthesized and employed as a multi-functional additive for EP with simultaneously excellent flame retardancy, transmittance, mechanical enhancement and anti-aging. With 5 wt.% loading of HP-DOPO, EP composites showed outstanding flame retardancy with a high limiting oxygen index of 35.6 % and V-0 rating in UL-94 test, while the cone calorimetric test results demonstrated that HP-DOPO could efficiently restrain the heat and smoke release. Compared with pure EP, the resultant EP/5 %HP-DOPO exhibited superior mechanical properties with 27.9 % and 56.2 % increase in tensile and impact strengths, respectively. Furthermore, HP-DOPO accelerated the curing procedure and did not sacrifice the transparency of cured EP, while anti-aging performance was obtained at the same time. The exploration of this novel multi-functional additive provided a powerful basis for the technologies and potential industrial applications of epoxy materials.

Investigation on the Performance of Fire and Smoke Suppressing Asphalt Materials for Tunnels

The volatilization of asphalt fumes not only affects the health of construction workers, but also damages the environment. It even affects the construction quality of asphalt pavement in tunnels. This article focuses on solving the emission of asphalt fumes to better protect human health and the environment, while satisfying the use of asphalt pavement. A flame retardant and smoke suppressant (compound) with Mg(OH)2 as the main component was developed, and flame retardant asphalt mixture and asphalt mastics were prepared to evaluate the flame retardant and smoke suppressant properties and performance effects. Firstly, its low- and high-temperature performances were investigated with BBR and DSR, respectively. Then, the indoor combustion test and the cone calorimeter test were used to evaluate the fire retardant smoke suppression effect of the asphalt mastic. Thirdly, the flame retardant effect of asphalt mastic mixed with the compound was further analyzed by the TG test and SEM. The pyrolysis temperature, mass loss, and microscopic state of the asphalt surface were used to verify and explain the flame retardant reaction effect and process of the compound. Finally, the asphalt mixture performance was evaluated, as well as the flame retardant smoke suppression effect by asphalt mixture combustion tests. The results showed that the flame retardant smoke suppression time of the flame retardant asphalt mixture was reduced by 66%, and the smoke emission area was reduced by 20%. The flame retardant smoke suppression effect of the asphalt mixture was improved by 44%. It is proven that this kind of fire retardant and smoke suppressing asphalt mastic and mixture met performance needs in use, and the fire retardant and smoke suppressing effect was obvious. This solution addresses the issue of asphalt smoke generated during the construction of asphalt pavement, providing better support for the construction of asphalt pavement in tunnels.

Multifunctional and sustainable DOPO-derivative coating for flame-retardant, antibacterial and UV-protective of polyamide 56 protective biomaterials

Polyamide 56 (PA56) biomaterial with excellent flame retardancy, antibacterial and UV-protective properties is potentially applied in the field of security and protection. Here, a green and sustainable multifunctional coating (DOPO-ATU) was developed, and then it was applied to modify PA56 fabric. The DOPO-ATU showed excellent flame retardancy to PA56 fabric. With 7.8 % weight gain, the coated PA56 fabric possessed a high LOI value of 30.1 % and a low damaged length of 11.1 cm without dripping. In cone calorimeter test, the peak heat release rate and average effective heat of combustion decreased by 20.5 % and 46.4 % versus pristine one, showing excellent fire safety. Further analysis proved that DOPO-ATU mainly acted in the gas-phase through the action of diluting non-combustible gases and quenching free radicals. In addition, the coated PA56 fabrics also displayed excellent antibacterial property and UV-protective properties. This work provides a cleaner and sustainable approach for preparing multifunctional coating for PA56 protective biomaterials.

An exploratory investigation into moisture content and wind impact on the fire behaviour of modular living walls

Vertical greenery systems (VGS) consist of vegetation biomass and organic materials as well as plastics or metal elements in supporting systems. In this work, we investigate fire properties of live and dead plants as part of complete VGS systems (living walls, LW). Small-scale tests using a cone calorimeter and medium-scale tests using the SBI method were used to determine reaction to fire properties. Full-scale experiments were carried out to approximate the flame spread with and without wind along a living wall. Highly moist plants lead to slower spread of the fire, but have not prevented spreading the fire on the plastic potting, which in all cases was eventually involved in the fire and burned down to a collapse. On dry vegetation and without wind, the vertical flame spread velocity was up to 90 cm/s, and horizontal up to 2.7 cm/s. Wind conditions have changed the living wall fire performance, accelerating the fire spread on the vegetation and the fire of plastic potting as well. For moist samples in PN-B 02867 test the test duration (until full destruction of the facade) was 2100 s without and 1150 s with wind. For dry samples, this was 1350 s and 590 s, respectively.