Cone Calorimetry Test Research Articles

Preparation and performance analysis of organic polyborosilazane-modified epoxy resin-based intumescent flame-retardant thermal insulation coatings

To improve the thermal insulation and flame retardancy properties of epoxy resin-based intumescent coatings, this study served epoxy resin (EP) as the base material, melamine (MEL), pentaerythritol (PER), and ammonium polyphosphate (APP) as the blowing agents, char-forming agents, and dehydration catalysts, palgorskite and sepiolite as fillers, and PSNB as the modifying agent to prepare the high-performance modified coatings by using the straightforward blending modification technique. With the introduction of PSNB, the coating achieves an in-situ vitrification/ceramisation effect in the char structure when exposed to fire, thus fully enhancing its fire protection capability Compared to the blank sample (EPC), the modified coating (EPC-PSNB-3) exhibited optimal performance when the PSNB content reached 30 wt%. In a 2 h thermal insulation performance test, the substrate backside temperature of EPC-PSNB-3 was only 165.99 °C. The Limiting Oxygen Index (LOI) value increased by 33.20 %. In cone calorimetry tests, EPC-PSNB-3 showed reductions of 63.56 %, 64.98 %, 21.37 %, and 24.35 % in peak heat release rate (PHRR), peak smoke production rate (PSPR), total heat release rate (THR), and total smoke production (TSP), respectively, compared to EPC. The residual char mass increased by 45.19 % with PSNB incorporation. The introduction of PSNB not only promotes the increase of residual char but also densifies its internal porous structure, enhancing its thermal barrier capability.

A high-molecular-weight flame retardant derived from bis[tetrakis(hydroxymethyl)phosphonium] sulfate for cotton fabrics

A high-molecular-weight flame retardant, bis[tetrakis(hydroxymethyl)phosphonium] (THPS)-urean-(PO3)(NH4)2, was synthesized for cotton fabrics. Fourier-transform infrared spectroscopy, nuclear magnetic spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy analyses confirmed that (THPS-urea)n-(PO3)(NH4)2 effectively infiltrated the fibers and grafted onto cellulose through N–P(=O)–O–C covalent bonds. The fabric treated with 30 wt% of (THPS-urea)n-(PO3)(NH4)2 (C30) had a limiting oxygen index of 46.8 %. Even after 50 laundering cycles according to the AATCC 61-2013 3A standard, C30 maintained a limiting oxygen index of 39.8 %. Thermogravimetric-Fourier-transform infrared spectrometry, thermogravimetry, and cone calorimetry tests revealed that C30 exhibited excellent flame retardancy. Upon exposure to flame, C30 formed a stable char layer, which prevented the spread of heat and combustible gases. Additionally, C30 was free of formaldehyde, making it suitable for producing infant textiles. After grafting with the flame retardant, C30 retained its mechanical properties. The high-molecular-weight flame retardant enhanced the flame resistance and durability of cotton materials owing to its numerous N–P(=O) (ONH4)2 groups, which facilitated a condensed-phase flame retardancy mechanism.

Green synthesis of a novel P/N/S containing bio-based flame retardant and its applications in poly(lactic acid): rapid self-extinguish, anti-dripping, and excellent mechanical performance

Poly(lactic acid) (PLA), which is recognized as a potential biodegradable material, brings serious fire concern because of its flammability with heavily molten drips. In this investigation, a bio-based flame retardant named CS@ATMP@MI (CAM) consisting of chitosan (CS), amino trimethylene phosphonic acid (ATMP), and methionine (MI) was developed through a simple and environmental-friendly synthesis approach. CAM provided effective flame retardancy and anti-dripping ability without compromising mechanical properties. PLA/CAM composites achieved a UL-94 V-0 rating with 1.0 wt% CAM and a limited oxygen index value of 28.4 % with 3.0 wt% CAM. The high efficiency is due to the high phosphate content in ATMP and the strong coordination between CS, ATMP, and MI. The cone calorimetry tests showed that adding 2.0 wt% CAM increased the total smoke production from 0.2 to 0.6 m2, and thermogravimetric analysis/infrared spectrum analysis indicated that combustible gas production was reduced over 50 % with 3.0 wt% CAM, demonstrating that phosphorus-nitrogen synergy in CAM could effectively capture free radicals and released inert gases. Char analysis showed that the PLA/CAM composites could form a thicker and denser char layer during combustion due to phosphorus-sulfur synergy, which promoted char formation to shield mass transfer. PLA/CAM composites maintained excellent mechanical performance, with a 3.0 wt% CAM increasing tensile strength from 53.9 to 57.3 MPa and Young's modulus from 1782 to 2262 MPa. This study presented a sustainable method for synthesizing an effective bio-based flame retardant and a strategy for producing eco-friendly, fire-resistant PLA composites for industrial applications.

Flame retardant, transparent, low dielectric and low smoke density EP composites implemented with reactive flame retardants containing P/N/B

For the purpose of investigating the modified flame-retardant epoxy resin (FREP) with the low smoke density release during combustion, the flame retardant containing P/N/B elements named DBT was synthesized with the raw materials of 4-Acetylphenylboronic acid, 3,5-diaminotriazole and DOPO. The DBT was added as a co-curing agent to an amine-cured epoxy resin system, and based on the DSC results of the resin, it was revealed that -NH- in the structure of the DBT was capable of facilitating EP curing. With the introduction of DBT, the transparency of FREP samples was slightly affected. On account of the excellent flame retardancy exerted by the DBT in the FREP system, the FREP samples reached the V-0 grade in UL-94 testing with an LOI of 35.9% at 5 wt% DBT addition. Meanwhile, the results of the cone calorimetry test demonstrated that in comparison with the epoxy resin, the PHRR, THR and av-EHC of the EP/DBT7.5 sample decreased by 34.0%, 35.4% and 18.68%, respectively. The DBT was effective in reducing the smoke density of EP, and the EP/DBT7.5 sample attained the HL1 level for DS (4) and VOF4. The chemical analyses for residual char revealed that DBT was mainly employed for flame retardancy and smoke suppression by forming P/B-containing chars in the condensed phase. There was no loss of mechanical properties of the FREP samples as the rigid groups were present in the DBT structure. Furthermore, it was noted that the FREP samples exhibited a decrease in dielectric loss and dielectric constant as the content increased.

High rubber elasticity and thermal conductivity in plasticized polyvinyl chloride film with flame retardancy and smoke suppression properties

AbstractFor hydrogenated nitrile‐butadiene rubber (HNBR) modified polyvinyl chloride (PVC), magnesium hydroxide and antimony trioxide are frequently employed as flame retardants. Fume silica is thought to be useful reinforced agent for rubber as well as efficient flame retardant for polymer‐based composites. The plasticized PVC and HNBR blend in this work were combined with three fillers mentioned above to create rubber‐plastic composites that performed well overall, with a notable improvement in combustion. The limiting oxygen index of the composites increased from 23.7% to 33.8% with no droplets falling during combustion, the smoke density rating decreased from 23.8% to 7.9%, and the maximum smoke density dropped from 95.5% to 15.5%. The cone calorimetry test findings revealed that the three fillers simultaneously prevented the emission of smoke and heat from combustion. High thermal conductivity is typically linked to excellent flame retardancy. The thermal conductivity of composites rose from 0.193 to 0.583 W m−1 K−1 with the addition of fillers. Furthermore, the low glass transition temperature and permanent set of improved composites reflect its softness and rubber elasticity. Thermogravimetric analysis was used to examine the thermal stability of the composites in nitrogen and air, and the results indicated the addition of fillers improved the thermal stability.

Schiff base approach to introduce chitosan-phytic acid complex for flame-retardant cotton fabrics

In this study, chitosan was integrated onto cotton fabric fibers through a Schiff base reaction, followed by the in-situ generation of Chitosan-Phytic acid (CH-PA) complex to achieve green flame retardancy. The process began with oxidizing the fabric using sodium periodate (NaIO4) to create numerous aldehyde groups on the fiber surface. Subsequently, CH was grafted onto the fabric via a Schiff base reaction. The fabric was then immersed in a PA solution to form a CH-PA complex, resulting in a novel and highly efficient flame-retardant (FR) fabric. The structure of the treated fabric was analyzed by using Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS), confirming the successful formation of the desired structure. The thermal stability and flame retardancy of the fabric were systematically evaluated using thermogravimetric analysis (TGA), cone calorimetry (CONE), vertical combustion tests, and limiting oxygen index (LOI) measurements. The LOI increased from 17.6 % to 30.6 %, and vertical combustion tests demonstrated self-extinguishing capabilities when the fabric was treated by the NaIO4 solution at concentrations of 0.02 g/mL or higher. In the CONE test, the modified fabric showed significant improvements, with peak heat release rate (pHRR) and total heat release (THR) decreasing by approximately 80 % and 60 %, respectively. Comprehensive analysis indicated that the FR mechanism involved both gas phase and condensed phase actions. Further characterization of the material included tensile testing and wash resistance assessments. By comparing these findings with recent research on similar topics, the advantages and disadvantages of the materials were thoroughly evaluated. Notably, this work provides a robust experimental foundation and conceptual expansion for the green flame retardancy of cotton fabrics.

Pyrolysis models for pressure treated wood and wood–plastic composite

AbstractPressure treated wood (PTW) and wood–plastic composites such as Trex® are popular materials for the construction of decks and other auxiliary structures, which are known to significantly contribute to spread of wildland fires into communities. In this work, representative samples of these materials were studied to determine their pyrolysis and combustion properties to enable simulation of fire growth on the surface of these building products. The pyrolysis property development process followed a well‐established hierarchical approach where thermogravimetric analysis, differential scanning calorimetry, and microscale combustion calorimetry were used to parametrize kinetics and thermodynamics of the thermal decomposition and combustion, while controlled atmosphere pyrolysis and cone calorimetry tests performed on coupon‐sized samples were used to parameterize thermal transport properties and validate performance of the fully parametrized pyrolysis models. PTW decomposition was captured using four sequential reactions with one additional reaction used to model vaporization of water. Trex® board was found to consist of two distinct layers: a thin outer layer and an internal core. The pyrolysis model for this material was constructed using some known properties of high‐density polyethylene (PE) and the properties of PTW determined in this work. The outer layer was defined in the model to consist of PE and an inert additive, while the core was defined as a blend of PE and wood particles, which kinetics and thermodynamics of the thermal decomposition and combustion were successfully captured using the model developed for PTW.

Effect of expanded perlite as an environmentally friendly flame‐retardant in semi‐rigid polyurethane foam

AbstractThe objective of the present study is to synthesize semi‐rigid polyurethane foam/expanded perlite (SrPUF/EP) composites using different amounts of EP, a natural and environmentally friendly alternative to traditional halogen‐containing flame‐retardants in a one‐step process. This study investigates the mechanical, physical, thermal, and morphological properties, as well as the flame‐retardant and smoke release behaviors of composites. The cone calorimetry test results indicated that the amounts of carbon monoxide and carbon dioxide released during combustion process decreased by 43% and 37%, respectively, in the 8% EP‐added SrPUF/EP composite (4SrPUF). The amount of char residue formed after complete combustion of 4SrPUF composite was found to be 2.7 times higher than that of pure SrPUF. In the UL‐94 test, it was observed that when 4% or more EP was added to SrPUF, the liquid dripping during combustion ceased entirely, and after complete combustion, the main structure remained in the form of char without disintegration. The flexural strength of 1SrPUF, 2SrPUF, and 3SrPUF exhibited increases of 62%, 69%, and 121%, respectively, in comparison to SrPUF (47.15 kPa). The results of this study indicate that EP has the potential to serve as an environmentally friendly and cost‐effective flame‐retardant, thereby enhancing the fire resistance properties of SrPUF.

A P/Si-containing flame retardant towards simultaneous improvement of the toughness, transparency and fire safety of polycarbonate

Polycarbonate (PC) is a commonly used engineering plastic, but its poor flame retardancy limits its use. In this study, a DOPO-based flame-retardant (DOPO-TMTA) containing P and Si elements was synthesized via a simple method involving 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and 2, 4, 6-trivinyl-2, 4, 6-trimethylcyclotrisiloxane (TMTA). The PC/mDOPO-TMTA (m = 4, 6, 8) composites were prepared by melt blending PC with different loadings of DOPO-TMTA. The prepared PC/DOPO-TMTA composites had excellent flame retardancy while maintaining good transparency. The limiting oxygen index (LOI) of PC/8DOPO-TMTA reached 32.5 % and achieved a UL-94 V-0 rating. Moreover, cone calorimetry tests revealed that, compared with those of pure PC, the peak heat release rate (PHRR) and total heat release (THR) of PC/8DOPO-TMTA decreased by 39.0 % and 38.1 %, respectively. Compared with pure PC, PC/mDOPO-TMTA also maintained good mechanical properties, and the tensile and impact strengths were slightly improved. The synergistic flame retardancy of DOPO-TMTA on P/Si elements for the PC matrix was revealed by condensed phase and gas phase product analysis. This work provides a good reference for the preparation of PC composites with high transparency and excellent comprehensive properties.

Investigating Intumescent Flame-Retardant Additives in Polyurethane Foam to Improve the Flame Resistance and Sustainability of Aircraft Cabin Materials

Polyurethane (PU) foam has a high flammability and is widely used in aircraft interiors, presenting a significant danger to occupants. This study analysed three composite intumescent flame-retardant (IFR) coatings for flexible PU foam; expandable graphite (EG), ammonium polyphosphate (APP) and alginate (AG). The coatings were prepared in concentrations of 5 wt%, 10 wt%, and 50 wt% with an acrylic binder. The coated samples were characterised using cone calorimetry, SEM, and mechanical testing. The findings showed peak heat release rate, total heat release, and carbon dioxide production from the 10 wt% triple-layer coating (EG:APP:AG) was 52%, 32%, and 58% less than the PU control. The char of the 10 wt% triple-layer sample effectively suppressed smoke release and inhibited the transfer of fuel and gas volatiles. Mechanical testing demonstrated a 3.4 times increase in tensile strength and a 15.4 times increase in compressive strength (50% compression) compared to the control PU with the 10 wt% triple-layer coating. A fire dynamics simulator model was developed that demonstrated large-scale flammability modelling for commercial aircraft. Future work can explore the integration of IFR coatings into computational analysis. These new bio-based coatings produced promising results for aircraft fire safety and flammability performance for PU polymers.

Phytic acid-induced durable fire-proof and hydrophobic complex coating for versatile cotton fabrics

To address the current development requirements for multifunctional cotton fabrics, a phytic acid-induced flame-retardant hydrophobic coating containing nitrogen (N), phosphorus (P), and silicon (Si) was grafted on the surface of cotton fabrics using a facile step-by-step immersion method. The limiting oxygen index value improved to 31.2 %, decreasing to 26.7 % after 50 laundering cycles, while the fabric remained self-extinguishing effect in the vertical flammability test and showed a water contact angle of 126.1°. Cone calorimetry test showed that the modified fabric could not be ignited at the irradiation heat flux of 35 kW/m2. When the irradiation heat flux was raised to 50 kW/m2, there was a significant decline in the peak heat release rate of the modified cotton fabric, which decreased by 43.2 % to a remarkably low value of 114.0 kW/m2, indicating excellent flame-retardant properties. The analysis of the flame-retardant mechanism uncovered that the modified coating exhibited a significant dual flame-retardant mechanism involving both the gaseous phase and the condensed phase. Additionally, the oil-water separation tests revealed that the separation efficiency of the modified cotton fabrics was as high as 97.1 % and remained around 96 % after 10 cycles, which made them reusable for the clean-up of hazardous chemicals.

Engineering sulfonated carbon black for flame-retardant and smoke-suppressive polycarbonate with well-preserved mechanical performances

To cope with the practical demands of high-performance polycarbonate (PC) and explore the application of carbon black (CB) in flame retardant field, a sulfonated carbon black (CB-SS) was synthesized and applied to flame retardant PC in this work. Compared with PC/CB composite, PC/CB-SS composite displays better overall performances under the same flame retardant addition. The PC/3CB-SS composite with 3 wt.% of CB-SS achieves a vertical burning test (UL-94) V-0 rating with a limiting oxygen index (LOI) of 29.5%, and its peak heat release rate (PHRR) and total smoke release rate (TSR) are respectively reduced by 17% and 6% relative to those of PC/3CB with 3 wt.% of CB. The flame retardancy mechanism is proposed by analyzing the char residue obtained from cone calorimetry test, which confirms the synergistic flame-retardant effect between sodium sulfonate and CB in condensed phase. Moreover, PC/3CB-SS shows much better mechanical properties than PC/3CB, and its elongation at break is increased by 223% compared with that of PC/3CB. This is mainly due to the more even dispersion of CB-SS within PC and the stronger interfacial force between CB-SS and PC. This work provides an effective approach for the creation of fire-retardant and smoke-suppressive PC composites with well-preserved mechanical properties, contributing to expanding the industrial applications of PC.

Effect of silane coupling agent on mechanical properties, flame retardancy, and ceramifiable behavior of ceramifiable flame‐retardant silicone rubber composite

AbstractIn order to improve the dispersibility of inorganic fillers and enhance its ceramifiable flame‐retardant efficiency, the ceramifiable flame‐retardant silicone rubber composites were prepared using glass powder, zinc borate, ammonium polyphosphate, mica powder, platinum catalyst as ceramifiable flame‐retardant agent, and various silane coupling agents as interfacial modifier. The micromorphology, mechanical properties, flame retardancy, thermal stability, and combustion behavior of ceramifiable flame‐retardant silicone rubber composites, as well as the flexural strength of the corresponding ceramics generated after pyrolysis of the composites were examined. The results reveal that the inclusion of silane coupling agents improves the dispersibility of ceramifiable flame‐retardant agents substantially. The mechanical properties, flame retardancy, thermal stability, and combustion behavior of ceramifiable flame‐retardant silicone rubber composites are all improved. When compared to a composite without a silane coupling agent, the tensile strength of the composite can be improved by up to 1.9 times. Only 0.5phr silane coupling agent is required to raise the vertical combustion rating from V‐1 to V‐0, and the composite with 3 phr KH570 has a LOI value of 38.6. Meanwhile, the heat release rate of the composite is reduced to a certain extent, and the time to ignition and residue are dramatically enhanced after the addition of silane coupling agent in the cone calorimetry test. Moreover, flexural strength of the corresponding ceramics generated after pyrolysis of the composites rapidly increases with increasing silane coupling agent content, which can reach to 24.7 MPa with addition of 3 phr KH570.

Investigation of the Effects of Phosphate-Containing Flame-Retardant Chemicals on Particleboards Produced Using Urea-Formaldehyde Resin.

In this study, urea-formaldehyde resins containing different phosphate-based flame retardants (FRs) were prepared to produce wood-based panels (medium-density fiberboard, particleboard, and veneer board), and their flammability properties were investigated. The changes in the gelation times were investigated when the phosphate-containing FRs used in different amounts were mixed with the resin. Chemicals that have both hardener and flame-retardant properties at the same time have been studied. In addition, the pH and thermal analyses of the resin and flame-retardant mixtures prepared in this study were performed by a pH meter and thermogravimetric analysis, respectively. The limiting oxygen index, UL-94 vertical burning, and cone calorimetry tests on the samples with the best combustion characteristics were carried out by sizing the particleboards in accordance with the standards and applying the prepared flame-retardant resins on them. The distribution of flame-retardant resin on the particleboard surface was investigated for the samples prepared by scanning electron microscopy. As a result of the analyses, it was determined that the samples containing 20% ammonium polyphosphate had good nonflammability properties.

Construction of a β-cyclodextrin-based colloid containing silicon, phosphorus and nitrogen components: Toward enhancing flame retardancy of flax fabrics

Natural cellulose fabrics, as one of the combustibles prone to causing indoor fires, are modified with flame retardants encouraged by the fire protection industry. Herein, a bio-based colloid named ASDPC was prepared by 3-aminopropyltriethoxysilane, diethylenetriaminepentakis(methylphosphonic acid) and β-cyclodextrin, and used to enhance the flame retardancy of flax fabrics via the pad-dry-cure method. The treated flax fabrics named ASDPC-FF showed good flame retardancy with a damaged length of only 6.4 cm in the vertical burning test and a limiting oxygen index value of up to 33.8 %. Meanwhile, ASDPC-FF exhibited thermal stability and combustion behavior distinct from untreated flax fabrics. Thermogravimetric analysis presented that the char residue produced by ASDPC-FF at 800 °C was as high as 36.2 %. Cone calorimetry test indicated that the peak heat release rate and total heat release of ASDPC-FF decreased by approximately 89.0 % and 35.7 %, respectively. Furthermore, compared to untreated flax fabrics, condensed-phase and gas-phase studies found that ASDPC-FF turned into expanded char and produced fewer gaseous volatiles containing C-H, CO and C-O-C at high temperatures. More importantly, ASDPC-FF remained self-extinguishing after 25 laundering cycles with flame retardancy surpassing untreated flax fabrics. In summary, this work provides a novel route for expanding the manufacture of flame-retardant flax fabrics.

Self-crosslinking phosphorus-containing durable flame retardants for cotton fabrics

The phosphorus-containing flame retardant that can enter the interior of cotton fiber and has self-crosslinking ability was designed and synthesized. The flame retardant contains two components, 2-(1-(dimethoxy phosphoryl)-2,5, 8-Triazectridecyl) phosphonate starch (PTPS) and 4-(hydroxymethyl)-10-((3-((5-(hydroxymethyl)-10-((3-((tris(hydroxymethyl)phosphonio)methyl)ureido)methyl)-2,6,8,12,14,18-hexaaza-4,10,16-Triphosphanonadecane (BPTP). The structure of PTPS and BPTP were detected by NMR and FTIR, and the results showed that the synthesis of PTPS and BPTP was successful. During the treatment, cellulose was first endowed with -NH groups. Then PTPS molecule and BPTP molecule were grafted onto cellulose through the reaction of P-CH2OH groups and -NH groups. After 50 laundering cycles (NFPA2112–2012 standard), the limiting oxygen indexes (LOIs) of the fabrics treated with 35 wt% CFN-PB and 30 wt% CFN-PB were 28.80% and 27.30%, respectively, and passed the vertical flame test (VFT). Compared with the raw cotton, the peak heat release rate (PHRR), the total heat rate (THR) and the flame growth rate (FGR) of the CNF-PB treatment fabric were reduced by 62.90 %, 29.43 % and 62.91 % respectively. These indicate that the flame retardant PB could be firmly fixed on the fibers and show good flame retardancy durability. In the VFT, and cone calorimetry test, the CFN-PB treated fabric showed the condensed phase flame retardant mechanism.

Composite silica aerogel based on HNTs-modified APP with enhanced thermal insulation and flame retardancy performance for organosilicon resin

Efficient thermal insulation and flame-retardant materials are crucial in reducing energy consumption and minimizing fire hazards. This work presents a novel method for preparing a composite aerogel: a silane coupling agent was used as a chemical bridge to synthesize a new flame retardant AKH (modified APP with HNTs). AKH was incorporated into the silica sol to fabricate the SA-AKH composite aerogel. SA-AKH features a dense three-dimensional network skeletal structure, excellent thermal stability, and a high specific surface area. When integrated into organosilicon resin, SA-AKH significantly enhances the flame resistance of composite materials. During cone calorimetry testing (CCT), SSAKH4 exhibited a peak heat release rate (PHRR) of 281.88 kW/m2 and total smoke production (TSP) of 5.52 m2, representing a decrease of 30.8 % and 4.5 %, respectively, compared to SSA4. The composite material, derived from the unique mesoporous structure of aerogel combined with the flame retardant and hollow characterization of AKH, demonstrates exceptional flame retardancy and smoke suppression. SA-AKH is expected to make novel advancements in the field of high-efficiency insulation and flame-resistant composites.

Enhancing the flame retardancy of polycarbonate through the synergistic effect of 1,3‐Benzenedisulfonate acid dipotassium salt and phenyl polysiloxanes

AbstractAs the application of polycarbonate (PC) in various fields continues to expand, the requirements for its flame retardancy are becoming increasingly stringent. To enhance the flame retardancy of PC, employing multi‐element synergistic effects and developing novel flame retardants are considered as vital strategies. This work introduces a blend of 1,3‐Benzenedisulfonic acid dipotassium salt (KSP) and three types of phenyl polysiloxanes, namely Octaphenylcyclotetrasiloxane (P4), Octaphenylsilsesquioxane (OPS), and ladder‐like Polyphenylsesquioxane (L‐PPSQ), into PC to create composites. The thermal stability and combustion properties of these composites were characterized using thermogravimetric analysis (TGA), limiting oxygen index (LOI), UL‐94 vertical burning, and cone calorimetry tests. Composites with phenyl polysiloxanes achieved a UL‐94 V‐0 flame retardant rating for 1.6 mm thickness sample and reduced the peak heat release rate by 30%–45%. PC composites with 3% OPS and 0.03% KSP achieved optimal performance, howing a LOI of 34.5%, a 45.4% reduction in peak heat release, and a 40.5% reduction in total smoke release. The flame‐retardant mechanism was analyzed using scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), and pyrolysis‐gas chromatography‐mass spectrometry (Py‐GC‐MS).

Fabrication of Flame-Retardant Ammonium Polyphosphate Modified Phytic Acid-Based Rigid Polyurethane Foam with Enhanced Mechanical Properties.

Ammonium polyphosphate (APP) and self-made nickel phytate (PANi) were used as modified materials to prepare green biomass rigid polyurethane foam (RPUF). The flame retardancy, thermal stability, smoke toxicity and mechanical properties of the modified RPUF were investigated by limiting oxygen index (LOI), a cone calorimetry (CONE) test, thermogravimetric analysis and a compression test. The results showed that the RPUF with 10 wt% APP (PANi/APP10) had the highest LOI of 26.5%. Its peak heat release rate (PHRR) and total heat release (THR) were reduced by 29.64% and 24.05% compared with PANi/APP0 without APP. And its smoke production rate (SPR) and total smoke release (TSR) decreased by 33.14% and 19.88%, respectively. Compared with pure RPUF, the compressive strength of PANi/APP10 was increased by 50%, mainly because APP itself was an ultra-fine powder, which was better compatible with the matrix and improved the hardness of the material. The results showed that the synergistic effect of the gas phase and the condensed phase mechanism could effectively improve the flame-retardant effect. The current research results provided a new strategy for the preparation of green and low-toxicity RPUF.

Alkaline amino acid modification based on biological phytic acid for preparing flame-retardant and antibacterial cellulose-based fabrics

Cellulose-based fabrics have significant advantages, but their application scenarios are limited due to their flammability. This work used biomass phytic acid and protein decomposition products, alkaline amino acids (arginine, lysine, histidine) to prepare alkaline amino acid flame retardants (PALA, PALL, PALH), and they were utilized to endow Lyocell fabrics with flame-retardant and antibacterial properties. When the weight gain was about 16.0 wt%, PALA exhibited better flame-retardant effect, and the limited oxygen index value of PALA-Lyocell reached 47.1 %. In the cone calorimetry test, PALA showed the best flame-retardant efficiency in reducing flame growth index with a 92.0 % decrease in peak heat release rate. The results of thermogravimetric analysis coupled with Fourier Transform Infrared spectroscopy (TG-FTIR) and char residues indicated that the flame-retardant property of alkaline amino acid flame retardants was formed through the combined action of gas and condensed phases. In the antibacterial test, PALA had the highest antibacterial rate against Staphylococcus aureus at 97.2 %. Mechanical property, handle feeling, and whiteness results had indicated that alkaline amino acid based flame retardants had little effect on the physical properties of Lyocell fabrics. This work confirms alkaline amino acid based flame retardants have functions of flame-retardant and antibacterial properties, providing reference for the practical value of biomass in cellulose-based fabrics.