Bio-based Flame Retardant Research Articles

Facile and Bioinspired Approach from Gallic Acid for the Synthesis of Biobased Flame Retardant Coatings of Basalt Fibers.

A sustainable, bioinspired approach to functionalize basalt fibers with an innovative gallic acid (GA)-iron phenyl phosphonate complex (BF-GA-FeP), for the purpose of improving the flame retardancy in composite materials, is developed. BFs were at first pretreated with O3, obtaining surface free hydroxyl groups that allowed the subsequent covalent immobilization of biosourced GA units on the fiber through ester linkages. Phenolic -OH groups of the GA units were then exploited for the complexation of iron phenyl phosphonate, resulting in the target-complex-coated BF fiber (BF-GA-FeP). Microwave plasma atomic emission spectroscopy and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy analyses of BF-GA-FeP highlighted an increase in iron content, modification of fiber morphology, and occurrence of phosphorus, respectively. BFs, modified with a low amount of the developed complex, were used to reinforce a poly(lactic acid) (PLA) matrix in the production of a biocomposite (PLA/BF-FeP). PLA/BF-FeP showed a higher thermal stability than neat PLA and PLA reinforced with untreated BFs (PLA/BF), as confirmed by thermogravimetric analysis. The cone calorimeter test highlighted several advantages for PLA/BF-FeP, including a prolonged time to ignition, a reduced time to flame out, an 8% decrease in the peak heat release rate, and a 15% reduced fire propagating index compared to PLA/BF.

Flame retardance and fume inhibition of bio-based composite flame retardant on bituminous combustion and its numerical models

To investigate the effects of sustainable bio-based composite flame retardant (BCFR) on flame retardance and fume suppression of bitumen and establish unified combustion models of bitumen and BCFR bitumen, the mass loss and fume release during bituminous and BCFR bituminous combustion processes were studied using thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR) tests. Results show that when bitumen burns out, BCFR bitumen remains the residue rates of 33%, 28% and 21% at 5, 10 and 15 °C/min, respectively. BCFR dilutes active free radicals involved in combustion at early bituminous combustion stage, thus reducing the reaction rate, and then inhibits bituminous combustion by forming intumescent char layer, increasing the char yield of bitumen, strengthening the thermal stability of char produced from bituminous combustion. BCFR does not reduce the kinds of fume constituents released from bituminous combustion but inhibits the release of aldehydes and phenols mainly by suppressing the oxidation reaction at early bituminous combustion stage. BCFR can effectively suppress the fumes release amount during bituminous combustion at lower heating rates. The proportions of alkanes and ketones released at the second and third stages of BCFR bituminous combustion are larger than those of bituminous combustion by 9.27% and 5.8% at 15 °C/min, respectively. Although BCFR has limited inhibitory effects on fume release amount at a larger heating rate, it inhibits the volatilization and combustion of alkanes in bitumen. Meanwhile, the combustion models of bitumen and BCFR bitumen established can better reproduce TG test results. This study develops a cleaner and more efficient bio-based flame retardant, and provides a reliable bituminous combustion model for large-scale fire simulation.

Structure of Metal-Organic Frameworks Eco-Modulated by Acid-Base Balance toward Biobased Flame Retardant in Polyurea Composites.

Biobased-functionalized metal-organic frameworks (Bio-FUN-MOFs) stand out from the crowd of candidates in the flame-retardant field due to their multipathway flame-retardant mechanisms and green synthesis processes. However, exploring and designing Bio-FUN-MOFs tend to counteract the problem of compromising the flame-retardant advantages of MOFs themselves, which inevitably results in a waste of resources. Herein, a strategy in which MOFs are ecologically regulated through acid-base balance is presented for controllable preparation of Bio-FUN-MOFs by two birds with one stone, i.e., higher flame-retardant element loading and retention of more MOF structures. Specifically, the buffer layer is created on the periphery of ZIF-67 by weak etching of biobased alkali arginine to resist the excessive etching of ZIF-67 by phytic acid when loading phosphorus source and to preserve the integrity of internal crystals as much as possible. As a proof of concept, ZIF-67 was almost completely etched out by phytic acid in the absence of arginine. The arginine and phytic acid-functionalized ZIF-67 with yolk@shell structure (ZIF@Arg-Co-PA) obtained by this strategy, as a biobased flame retardant, reduces fire hazards for polyurea composites. At only 5 wt % loading, ZIF@Arg-Co-PA imparted polyurea composites with a limiting oxygen index of 23.2%, and the peaks of heat release rate, total heat release, and total smoke production were reduced by 43.8, 32.3, and 34.3%, respectively, compared to neat polyurea. Additionally, the prepared polyurea composites have acceptable mechanical properties. This work will shed light on the advanced structural design of polymer composites with excellent fire safety, especially environmentally friendly and efficient biobased MOF flame retardants.

Bio-derived polyphosphazene modified halloysite nanotubes as eco-friendly flame retardants to significantly reduce smoke release and enhance the fire safety of epoxy resin

At present, designing efficient bio-based flame retardants for epoxy resin (EP) and exploring low-toxicity and sustainable flame retardant strategies is still a great challenge. In this work, a novel bio-based hybrid flame retardant was successfully prepared by constructing a resveratrol-based cyclic cross-linked polyphosphazene (PPZ) shell on the surface of halloysite nanotube (HNT). The enhancement effects of HNT@PPZ on the fire safety of EP composites were investigated by thermal degradation, simulated fire performance (cone calorimeter test), gas-phase product analysis, and condensed-phase char residue analysis. Compared to pure EP, he total heat release (THR), total smoke production (TSP) and the average yield of carbon monoxide (Av-COY) of EP/3HNT@PPZ were reduced by 47.8 %, 46.5 % and 48.8 % respectively. Furthermore, the EP composites containing HNT@PPZ had a stable flame retardancy even after 6 months of natural aging. It was found the barrier effect of HNT@PPZ in condensed phase was further strengthened by the formation of new product aluminum phosphate, which formed a multiple protective char layer. Additionally, PPZ shell improved compatibility and dispersion of HNT in EP matrix, the mechanical properties of the composite with HNT@PPZ were improved significantly. This work proposed a feasible solution for the preparation of highly efficient bio-based flame retardants with excellent heat reduction and smoke toxicity reduction ability, which could be expected to broaden the application of biomass resources in the development of highly efficient flame retardants.

Bio-based flame retardant for manufacturing fire safety, strong yet tough versatile epoxy resin

Bio-based flame retardants have attracted growing attention for sustainability and comparable efficiency to petroleum-based counterparts but suffer from compatibility issues with epoxy resins and the trade-off between strength and toughness. Here, a Schiff base-derived phosphorus-based flame retardant (TV-DOPO) was developed from biobased vanillin and tyramine. In the presence of the binary curing agents, nanoscale in-situ constructive phase separation induced by hierarchical thermal curing process and strong hydrogen bonding provide the composite resin with enhanced both stiffness and toughness. The flexural and impact strengths reached 159 MPa and 55.4 kJ m−2, which were increased by 36.5% and 129.6%, respectively, compared with the pristine epoxy, meanwhile excellent flame retardance was well maintained (UL-94 V-0 rating). Remarkably, these conjugated phosphaphenanthrene-containing composite resins demonstrate excellent UV-shielding capacity and optical transmittance. In this work, in-situ construction of a crosslinked network with tunable size of phase separation domains can be simply achieved by modulating the ratio of binary curing agents, to fabricate epoxy resins with all-around enhanced performance.

Effect of synthesized lignin-based flame retardant liquid on the flame retardancy and mechanical properties of cotton textiles

The flammability of cotton (Gossypium hirsutum) is a significant concern for technical applications, prompting ongoing research into solutions to mitigate this risk. Traditional flame-retardant methods utilizing acid-based approaches are complex and can negatively affect the mechanical properties of textiles. To address these challenges, this study focuses on developing a liquid bio-based flame retardant (LBF) utilizing a lignin-silica-based liquid (LSL) extracted from rice husk (RH) (Oryza sativa ssp. japonica) and 9, 10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO). A one-pot dip-coating technique is utilized to treat cotton with the LSL, and the flammability and mechanical properties of the treated cotton are subsequently tested. Fourier-transform infrared spectroscopy (FTIR) confirms the covalent bond formation of the LSL with DOPO and the hydrogen bond formation of the LBF with cotton. Scanning electron microscopy (SEM) confirms the uniformity of the coating. The experimental results demonstrate that the treated cotton exhibits self-extinguishing behavior during a vertical burning test (VBT), with a 78% reduction in peak heat release and a 65% reduction in total heat released during pyrolysis combustion flow calorimetry. Surprisingly, the treatment also improves the tensile behavior of the cotton by 21.7% and thermal stability by producing a protective char layer that accounted for 36.9% of the final residue. This study provides a promising approach for improving the flame resistance and mechanical strength of cotton for technical applications.

Bio-based flame retardants containing a biphenyl unit for enhancing mechanical properties and fire safety of epoxy resins

A reactive flame retardant containing biphenyl structure (DEU-2DOPO) was prepared from the bio-based raw material eugenol. The incorporation of DEU-2DOPO into the epoxy resin serves to enhance the ring-opening reaction of the epoxy. Furthermore, the inclusion of DEU-2DOPO has been found to have a positive impact on the glass transition temperature and residual carbon rate of the epoxy resin. This additive also significantly improves the mechanical properties of the epoxy resin, leading to a 49.3% increase in tensile strength, an 81.9% increase in breaking elongation, and a 15.8% increase in flexural strength. Notably, when DEU-2DOPO is introduced at a concentration of 5 wt%, it not only achieves a V-0 rating in the UL-94 test but also exhibits an impressive ultimate oxygen index of 34.5%. Additionally, the cone calorimetric testing revealed that the presence of DEU-2DOPO results in lower combustion metrics compared to pure epoxy, as evidenced by a reduction of 15.1% in total heat release (THR) and 10.8% in total smoke release (TSR). An analysis of the flame retardant mechanism elucidates that DEU-2DOPO promotes the formation of a stable and dense residual carbon, thereby impeding gas and heat exchange. Furthermore, the decomposition of DEU-2DOPO generates PO· and PO2· radicals, which effectively neutralize reactive radicals.

Flame retardant, high mechanical strength, transparent and water-resistant epoxy composites modified with chitosan derivatives

Adding bio-based flame retardants to improve the flame retardancy of polymer materials without sacrificing other properties is a great challenge. Herein, a novel flame-retardant CS-DOPA was prepared from chitosan and 10-hydroxy-9,10-dihydro-9-oza-10-phosphaphenanthrene-10-oxide by acid-base neutralization reaction and fully characterized. The 4 wt% CS-DOPA modified EP showed good flame retardancy in both gaseous and condensed phase. The peak heat release rate, total smoke production, CO production, and smoke production rate of EP composites containing 4 wt% CS-DOPA were reduced by 55 %, 34 %, 45 %, and 46 %, respectively, to pass the UL-94 V-1 rating with a limiting oxygen index of 34.1 %. The CS-DOPA contributes to the formation of the condensed phase of the thermo-oxidation-resistant high-quality char layer with non-flammable other and phosphorus-containing free radicals released in the gas phase. In addition, EP/4CS-DOPA has good water resistance, mechanical properties, and transparency, with tensile and flexural strength improved by 12.7 % and 13.9 %, respectively, and still has high strength even after water treatment. The present work provides a green and facile strategy to use chitosan as a main raw material to manufacture EP materials with high performance.

A universal eco-friendly flame retardant strategy for polylactic acid fabrics and other polymer substrates

Various polymer substrates have their particular combustion features, therefore, developing an effective universal flame retardant strategy for various polymer substrates is of great practical importance. Meanwhile, as substitutes for petroleum-based products, bio-based flame retardants and biodegradable polylactic acid (PLA) meet the requirements of sustainable development. In this work, a fully bio-based flame retardant coating (PAGS) was prepared using phytic acid (PA) and guanosine (GS). PAGS was used as a universal flame retardant coatings for polylactic acid (PLA) fabrics and other substrates, including cotton fabrics, polyethylene terephthalate (PET) fabrics, polyamide (PA) fabrics, polyurethane (PU) foams, polyethylene terephthalate (PET) films, and woods. The PAGS-treated substrates were able to self-extinguish and eliminate molten droplets. Similarly, the PAGS coating significantly suppressed the heat release of each substrate. The P-containing free radicals in the gas phase were able to interact with highly reactive H, HO and alkyl radicals, blocking the chain reaction during combustion. The flammable gas density was also diluted by nonflammable gases. The formed continuous porous and dense intumescent char layer hindered heat and oxygen. It is suggested that this work provides a simple and efficient flame retardant strategy for improving the fire safety of various polymer substrates.

Multifunctional polylactic acid sensing fabric based on biomass flame retardants for intelligent fire early-warning

Today, building materials emit many hazardous gases in the event of a fire, causing great harm to human health and the environment. Therefore, it is of great significance to develop bio-based flame retardant materials and to realize preventive measures to reduce fires or their damage. In this work, we fabricated a novel multifunctional fire early-warning polylactic acid-based fabric (MFR-PBF) by coating MXene nanosheet, phytic acid @ furfurylamine (PA@FA) and ammonium polyphosphate (APP) via an eco-friendly layer-by-layer assembly method. MFR-PBF showed outstanding flame retardancy including a limiting oxygen index value of 35 % and better char formation capacity. More importantly, MFR-PBF exhibited sensitive fire early-warning capability (∼1 s) and excellent cyclic alarm stability (>15 cycles) due to the excellent semiconductor responsiveness (light and heat) and the significant catalytic char formation effect. Moreover, MFR-PBF is comfortable, flexible and strong enough to sew onto firefighter uniform to detect a variety of human motions, which can be monitored in the internet by using a LoRa emitter and a gateway. In addition, the controllable heating performance rendered MFR-PBF as a potential portable heater. This work provides new insights into the preparation and application of intelligent fire early-warning fabrics in the smart fire protection and Internet of Things.

Novel fabrication of flame-retardant melamine sponge for all-weather cleanup of viscous oil spills by Joule heat and photothermal effects

Herein, we prepared a flame-retardant absorbent with high oil absorption capacity and outstanding photo/electrothermal conversion performance. Under sunlight irradiation or voltage, the sponge can achieve all-weather recovery of crude oil.

Infusing phytate-based biomass flame retardants into the cellulose lumens of Chinese fir wood attains superior flame retardant efficacy

To be suitable for certain construction and furniture applications, wood must be treated with a flame retardant and impregnating flame retardants into the cellulose lumens of wood is an effective flame retardant method. Phytic acid, the main storage form of phosphorus in various plant tissues, is an inexpensive, and non-toxic biomaterial that shows potential applications as an environmentally friendly bio-based flame retardant. In this study, phytic acid and zinc phytate were used to impregnate delignified wood under vacuum and pressure, which greatly enhanced the flame retardancy and smoke suppression properties of Chinese fir, while still maintaining its original texture. Phytic acid and zinc phytate were hydrogen-bonded to cellulose in wood. Phytic acid and zinc phytate were hydrogen-bonded to cellulose in wood. The results showed that the total heat release (THR) of Chinese fir treated with zinc phytate decreased from 55.66 MJ/m2 to 5.90 MJ/m2, and a compact carbonized protective layer was quickly formed on the surface of Chinese fir after ignition. Thermogravimetric analysis (TGA) showed that the char yield of Chinese fir treated by the flame retardant was 177.6 % higher than that of untreated wood. This study provides an efficient, sustainable, and economical method to prepare Chinese fir with excellent flame retardancy and thermal insulation performance.

Flame retardancy, thermal behavior and mechanical properties of an epoxy resin and cyanate ester resin copolymer containing a bio phytate-based flame retardant

In this research, a bio-based flame retardant (DNPA), was fabricated via a reaction involving a DOPO derivative (DOPO-NH2) and phytic acid, and was conducted by 1H NMR and FTIR. Then DNPA was incorporated into epoxy resin and cyanate ester resin copolymer (EPCE) to fabricate EPCE/DNPA composites. A comprehensive investigation was conducted to evaluate both the fire behavior, thermal performance and mechanical properties of the composites. Notably, the EPCE composite with 10 wt% DNPA (EPCE/10DNPA) achieved a V-0 rating and exhibited a 28.3 vol% LOI value. The EPCE/10DNPA demonstrated a 16.2 % decrease in the peak heat release rate value and a 13.9 % reduction in the total heat release value, respectively, compared to EPCE.

The synergistic flame retardant effect of biobased phytic acid arginine salt and hydroxylated montmorillonite in polybutylenes succinate

In this research, hydroxylated nano montmorillonite (DK2) was used as a synergistic agent in combination with phytic acid arginine salt (PaArg). The flame retardancy and mechanical properties of PBS with different amounts of PaArg and DK2 were studied. Furthermore, the synergistic effect and mechanism of PaArg and DK2 in PBS were explored. The results showed that adding 23.5 % PaArg and 1.5 % DK2 increased the limiting oxygen index value (LOI) of the composite to 31.4 %, passing the UL 94 V-0 rating. By adding 25 % PaArg alone, the LOI value of the composite is 26.2 %, and the vertical burning test result is only V-2 rating. The cone calorimetry test results show that the peak heat release rate, total heat release rate, and total smoke production of PBS/23.5 % PaArg/1.5 % DK2 composite are 55.8 %, 17.1 %, and 44.7 % lower than those of PBS/25 % PaArg composite, respectively. All the results showed that PaArg and DK2 exhibited good synergistic flame retardancy in PBS. In addition, the impact strength and bending strength test results show that the impact strength and bending strength of PBS/23.5 %PaArg/1.5 %DK2 composite are higher than those of PBS/25%PaArg composite. This work improved the flame retardant efficiency of biobased flame retardants in PBS.

Flame-retardant smoke-suppressing and antibacterial poplar wood enabled by a bio-based flame retardant containing transition metal

Utilizing bio-based flame retardants like chitosan (CS) and tannic acid (TA) is an effective way to enhance the flame retardancy of wooden products. In this work, the poplar wood was impregnated with composite flame retardants containing CS, TA, Cu (CH3COO)2·H2O and silane coupling agent (KH550). When KH550 bound these substances together to form a stable compound, a highly efficient flame-retardant wood (wood/CTA-Cu-Si) was prepared under vacuum pressure impregnation. The results of the functional group test show that bio-based flame retardants have been successfully synthesized. The limiting oxygen index (LOI) of the treated sample was reached 31.5%, the sample also passed the V-0 grade in the UL-94 vertical burning test, and in the Cone colorimeter test, the total smoke release was reduced by 50.2% compared to that of the Control. The energy dispersive spectroscopy proved that Cu and Si elements were evenly distributed in the wood before and after combustion. Raman spectra of the residues after the burning of treated wood were compared and it was found that the degree of graphitization of wood/CTA-Cu-Si was significantly increased, which ID/IG reached 1.85. After impregnation, the flame-retardant treated wood sample exhibited no negative effect on mechanical properties. The flame-retardant mechanism was probed and summarized as the Cu and Si synergistic promotion on charring and suppression on heat and smoke release. Simultaneously, the existences of Si-C, Si-O and Si-N strengthened the char layer and enhanced flame retardancy of poplar wood. Such resulted poplar wood with flame retardancy will be an excellent application prospect as engineering biomaterial.

Reducing fire hazards and enhancing the thermal stability, acoustical, and UV protection of polyvinyl alcohol using bio-based flame retardant

Polyvinyl alcohol (PVA) is a highly flammable material, and enhancing its flame retardancy to pass the glow wire test is a great challenge. In this work, the melamine salt of tannic phosphate (MTP) was synthesized, characterized, and combined with PVA at 8, 10, 13, and 15 wt%. The thermogravimetric analysis (TGA) results indicated that MTP enhanced the char formation of PVA at 750°C. Flammability tests showed that low concentrations of MTP can enhance the flame retardancy of PVA. The limiting oxygen index (LOI) of PVA increased from 18.8% to 39.9% in the PVA/15%MTP composite. The vertical flame spread test (UL94V) showed that PVA/13%MTP, and PVA/15%MTP composites achieved V0 rating. Glow wire test data indicated that PVA/10%MTP, PVA/13%MTP, and PVA/15%MTP composites had a glow wire flammability index (GWFI) of 960°C/2 mm. Moreover, all the composites passed the needle flame test when the flame application time was 120 s. PVA/15%MTP composite showed very good UV protection and an increase in sound absorption coefficient magnitude compared with pure PVA. The new results can increase the application of PVA in different industries.

Eco-friendly flame retardant coating based on ammonium polyphosphate and tyramine for lyocell fabrics

Low-carbon emissions are a sustainable development approach, among which lyocell is a renewable and zero carbon biodegradable cellulose fiber. The flammability of lyocell fabric poses a threat to people's lives and property. In response to this issue, a bio-based flame retardant, tyramine polyphosphate (APP-LA), was synthesized and applied to the treatment of lyocell fabrics. The synthesis of APP-LA adopted an eco-friendly and organic solvent-free method. In the combustion test, the limiting oxygen index of APP-LA treated lyocell fabrics increased to 35.8% compared to control lyocell (18.5%), and the damage length was only 6.7 cm. Meanwhile, the peak heat release rate and total heat release decreased by 92.9% and 58.7% respectively, compared to the control lyocell. Besides, the P-containing compounds generated by APP-LA accelerated the decomposition of the matrix to produce a dense char layer. The fewer flammable volatiles and more non-flammable gases were released. This work provided a low-cost and eco-friendly strategy for the simple preparation of commercial flame-retardant lyocell fabrics.

A green organic-inorganic PAbz@ZIF hybrid towards efficient flame-retardant and smoke-suppressive epoxy coatings with enhanced mechanical properties

Developing sustainable bio-based flame retardants for flammable polymers has been a research trend. However, applying bio-based flame retardants to confer excellent flame retardancy, smoke suppression, and mechanical properties to polymers remains a formidable challenge. Herein, a green organic-inorganic hybrid (PAbz@ZIF) was readily prepared through a simple neutralization reaction and in-situ generation method and applied to fabricate high-performance flame-retardant epoxy coatings (EP-PAbz@ZIF). It has been shown that PAbz@ZIF hybrids can enhance the curing activity of epoxy coatings in addition to their excellent dispersibility and interfacial compatibility. In addition, the epoxy coating containing 5.0 wt% PAbz@ZIF (EP-5%PAbz@ZIF) exhibits a higher char yield (from 25.1 wt% to 31.5 wt%) in comparison to pristine epoxy resin (EP). More importantly, the PAbz@ZIF-based epoxy coatings show more efficient flame retardancy and smoke suppression compared to pristine EP. For instance, the 5.0 wt% PAbz@ZIF enables EP-5%PAbz@ZIF to obtain a satisfactory UL-94 rating of V0. Meanwhile, the peak heat release rate, total smoke production, peak CO production rate, and peak CO2 production rate of EP-5%PAbz@ZIF are remarkably decreased by 48.6%, 20.5%, 38.6%, and 56.7%, respectively. Furthermore, EP-5%PAbz@ZIF exhibits enhanced heat insulation performance, flexural strength, and impact strength. This work offers a feasible idea for designing green organic-inorganic PAbz@ZIF hybrids and fabricating high-performance flame-retardant epoxy coatings.

Synthesis of a novel biobased tetrapod zinc oxide and synergy with melamine cyanurate to improve the flame retardancy and mechanical properties of epoxy resins

In this paper, based on phytic acid (PA), chitosan (CS) and tetrapod zinc oxide (TZ), a biobased flame retardant material (TZ@PA@CS) was synthesized by solution self-assembly method. A halogen-free green intumescent epoxy resin (EP) flame retardant system was composed of TZ@PA@CS and melamine cyanurate (MCA), and its thermal stability, flame retardancy, mechanical properties and related mechanism were studied in detail. The results show that the thermal stability of EP composites is improved after adding 3 wt% TZ@PA@CS and 5 wt% MCA into EP, and it can easily pass the UL-94 V-1 grade. At the same time, compared with pure EP, its peak heat release rate decreased by 44%, and the char residue rate increased by about 100% in cone calorimeter test. It is found that TZ@PA@CS and MCA have outstanding grading and synergistic flame retardant effects, and can form a dense, expansive and phosphorus-containing char layer. Besides, its impact and compression strength and compression deformation are increased by 41%, 39% and 155% respectively, which shows that it has good energy absorption, impact toughness and compression strength. This work provides a simple strategy for preparing biobased EP composites with excellent flame retardant properties, impact resistance and compression resistance.

Enhancement of fire resistance and mechanical performance of polypropylene composites containing cellulose fibres and extracellular biopolymers from wastewater sludge

In the present research, a bio-based flame retardant (FR) was prepared using a biopolymer derived from wastewater sludge to improve the fire performance of polypropylene (PP). Extracellular polymeric substances (EPS), which were extracted from wastewater aerobic granular sludge, were absorbed into cellulose-based fibres, such as flax and toilet papers. Thermogravimetric analysis results indicated that the EPS-cellulose fibres played a significant role in enhancing the char formation of PP composite. Furthermore, the incorporation of the bio-based FR into PP restricted its vertical burning characteristics, and at the same time enhanced the tensile moduli of the composites. The reaction between phosphoric acids from EPS and hydroxyl groups of cellulose fibres improved dehydration and char formation of the composites to enhance the overall fire reaction properties. This study opens up new possibilities for the wastewater-derived biopolymer “EPS” to prepare the bio-inspired FRs for cellulose-based fibres and composites, and enhance sustainability of wastewater sludge treatment.