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• Nano-Mg(OH) 2 and cyclic phosphate ester penetrated inside the fiber interior. • The modified R-PET exhibited durable flame retardancy without dripping. • The modified R-PET displayed significantly reduced smoke emission. • The organic-inorganic system offers high flame retardancy, wash durability and smoke suppression to R-PET textiles. Recycled poly(ethylene terephthalate) (R-PET) fabrics offer a sustainable and eco-friendly alternative to virgin PET but exhibit high flammability and increased smoke emission. In this study, magnesium hydroxide nanoparticles (nano-Mg(OH) 2) with the particle size of 53 nm were synthesized and combined with cyclic phosphate ester through high-temperature and high-pressure immersion technology. The organic‒inorganic flame retardant (FR) agents were expected to penetrate the R-PET fibers, thus achieving high washing durability for flame retardancy and smoke suppression. The surface structural performance of nano-Mg(OH) 2 and the smoke and heat suppression capacity, FR performance, mechanism and laundering resistance of the modified R-PET samples were also explored. The organic‒inorganic FR system significantly improved the FR properties and anti-dripping ability of R-PET while significantly reducing smoke and heat generation. Moreover, the modified R-PET fabrics exhibited self-extinguishing ability even after 40 washes, indicating their high washing resistance. The organic‒inorganic FR system was effective in both gas and condensed phase, providing multilevel fire safety. This study provides efficient and durable FR-functionalized R-PET fabrics with low smoke suppression and high fire safety. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • An adhesive and hydrotropic nanoparticle with a core–shell structure (Car@DOPO) was synthesized. • Car@DOPO nanoparticle endows polyamide 6 with excellent UV shielding and outstanding flame retardancy. • Carbohydrate Caramel shows promise as a biomaterial for improving the washing durability of functional textiles. • This work demonstrates the successful and sustainable treatment of Polyamide 6 fabrics using a carbohydrate polymer. The destruction of polyamide 6 (PA6) fabrics due to fire and prolonged UV radiation is an urgent issue that needs to be addressed. Inspired by the adhesion and inclusiveness of the sugar-coated haws, this study developed an adhesive nanoparticle with a core–shell structure (Car@DOPO) by encapsulating DOPO with carbohydrate caramel. The Car@DOPO nanoparticles exhibited excellent UV shielding property on PA6 fabrics, as indicated by a maximum UPF of 41.7, which can be attributed to the π-bonds and dark brown color of caramel shell. Additionally, the coated PA6 fabric demonstrated good flame retardancy, with a flame retardancy index (FRI) of 1.2. The LOI of coated PA6 fabric improved from 22.1% to 30.5%. Moreover, the fire growth rate (FGR) and flame inhibition effect (FIE) decreased by 13.3% and 22.0%, respectively. These improvements can be attributed to the efficient quenching effect of the DOPO core. Notably, the strong adhesion of the caramel shell allowed the Car@DOPO nanoparticles to firmly adhere to the fabric surface, providing coated PA6 fabric with durable flame retardancy. This study demonstrates the successful and sustainable treatment of PA6 fabrics using a carbohydrate nano-polymer. [ABSTRACT FROM AUTHOR]

The flame-retardant (FR) properties of polyurethane (PU)-coated polyester fabrics used in outdoor settings are unsatisfactory. This study aimed to enhance the FR performance of PU-coated polyester fabrics by synthesizing a series of metallic phytate salts through the chelation of phytic acid and four metal ions (Mg2+, Fe2+, Fe3+, Al3+). The flame retardancy, washing durability, mechanical properties, combustion performance, and FR mechanism of coated PET fabrics were investigated. Among the different metallic phytate salts, phytate aluminum salt exhibited stable FR efficiency without significantly affecting the mechanical performance of the fabric. The coated polyester fabric with 4 wt% phytate aluminum salt possessed a high LOI of 34.2 %, and achieved self-extinguishing action and met the requirements for B 1 classification. The coated fabric also displayed remarkable flame retardancy and durability, even after undergoing 50 washing cycles. Moreover, the addition of phytate aluminum salt resulted in a significant reduction of 34.3 % and 56.8 % in total heat and smoke release, respectively, indicating high fire safety. The phytate aluminum salt acted as a catalyst for the dehydration and carbonization of the PU-coated polyester in the condensed phase. This research introduces a novel approach for producing sustainable and long-lasting FR PU-coated polyester fabrics. [Display omitted] • Phytate salt is derived from resourceful plants or crops. • Phytate aluminum salt has high flame retardancy and washing durability on PU-coated polyester fabric. • Phytate aluminum salt significantly reduced the smoke and heat production of PU-coated polyester fabric. • Phytate aluminum salt offers an eco-friendly, long-lasting flame-retardant system for PU-coated outdoor polyester fabric. [ABSTRACT FROM AUTHOR]

• The coated polyester/spandex (T/S) fabrics displayed excellent washing and rubbing fastness. • The coated T/S fabrics had excellent UV protection and antistatic properties. • The coated T/S fabrics possessed significantly improved flame retardancy and anti-dripping performance. • This study offers a sustainable and promising technique to impart multi-functionalities to T/S fabrics. This study focused on the development of liquid carbon black nanoparticles (nano-CB) and the fabrication of black-colored polyester/spandex (T/S) fabrics with antiultraviolet, antistatic, and flame-retardant properties by a facile pad-cure technique. The flame retardancy efficiency and fastness of nano-CB on the fabric were enhanced by using a cyclic phosphate ester-based flame-retardant and polyacrylate adhesive binder HF-901. The morphology and particle size of nano-CB were investigated, and the color features, antiultraviolet and antistatic properties, combustion behavior, flame retardancy, and mechanism of coated T/S fabrics were also explored. The flaky nano-CB particles provided excellent light shielding and color fastness to the fabrics. The homogeneous coating of nano-CB also significantly improved the antiultraviolet and antistatic performance of the fabrics. Moreover, the coated T/S fabrics exhibited self-extinguishing capacity and a reduced damaged length of approximately 7.9 cm without molten drops. The formation of cross-linked char networks in the condensed phase and the trapping of combustible radicals in the gas phase during combustion synergistically enhanced the flame retardancy and anti-dripping capacity of the coated T/S fabrics. This study offers a facile and industrial applicable approach to enhance the multifunctionality of T/S fabrics and expand their potential applications. [Display omitted] [ABSTRACT FROM AUTHOR]

• A water-soluble polyelectrolyte complex was prepared using phytic acid and polyethyleneimine. • Polyelectrolyte complex was applied to wool textile by a single dip coating technique. • Polyelectrolyte complex coating imparted good flame retardancy to wool textile. • Polyelectrolyte complex coating had appreciable washing resistance on fabric surface. The one-step polyelectrolyte complex (PEC) deposition approach shows great potential and feasibility to prepare flame retardant (FR) textile materials. This study developed a water-soluble PEC system by using phytic acid (PA) and polyethyleneimine (PEI) at pH 1.5 to improve the flame retardancy of wool fabric. After being dipped in the PEC solution, the wool fabric was treated with the pH 4 buffer solution to form a water-insoluble coating on the fabric surface. The coated wool substrates had superior inflating ability during the thermal radiation and flammability tests, giving rise to the greatly suppressed heat and smoke generation performance, and increased FR efficiency of wool fabrics through an intumescent charring mechanism. The coated wool fabric with the PEC consisting of 15% PA and 15% PEI was still able to self-extinguish after 10 washing cycles, demonstrating its good FR ability and durability to washing. The appreciable washing durability of the coated wool could be attributed to the abilities of PA and PEI to combine with each other to form insoluble coating on wool fiber surface and to ionically and covalently cross-link with wool fiber. [ABSTRACT FROM AUTHOR]

Inorganic magnesium hydroxide nanoparticles (Mg(OH) 2 NPs) offer a promising halogen-/phosphorus-free flame-retardant solution for silk. However, achieving effective and durable flame retardancy remains a challenge. In this study, silane-modified Mg(OH) 2 NPs were prepared using the double drop-reverse precipitation method with the silane coupling agent 3-aminopropyltriethoxysilane as a surface modifier. The chemical bonding between silane-modified Mg(OH) 2 NPs and silk fabric was beneficial for improving the stabilization and durability of the functional particles on the silk surface. The surface morphology and structure of the silane-modified Mg(OH) 2 NPs, as well as the smoke and heat generation performance, flame retardancy, washing durability, and flame-retardant mechanism of the coated silk fabrics were investigated. The coated silk fabric exhibited high flame-retardant efficiency and significantly reduced smoke and heat generation, indicating a lower fire hazard. Additionally, the coated silk fabric displayed self-extinguishing behavior even after 15 robust washings, demonstrating high washing durability. The coated silk exhibited fibrous and weave structures after combustion, indicating a strong charring ability. Overall, this study presents a promising approach for the development of flame-retardant silk fabrics with excellent washing durability using inorganic Mg(OH) 2 NPs. [Display omitted] • Silane-modified magnesium hydroxide nanoparticles (Mg(OH) 2 NPs) is applied as inorganic flame-retardant coating for silk. • Silane-modified Mg(OH) 2 NPs coating endows silk textile with effective and durable flame retardancy. • Silane-modified Mg(OH) 2 NPs coating significantly suppresses the smoke and heat generation of silk textile. • Silane-modified Mg(OH) 2 NPs coating serves as a sustainable and promising technique to minimize fire hazards of silk textile. [ABSTRACT FROM AUTHOR]

A novel and durable organic-inorganic flame retardant (FR) system for wool fabric was fabricated using natural phytic acid (PA), titanium dioxide (TiO 2 ) nanoparticles and 1,2,3,4-butanetetracarboxylic acid (BTCA). In order to address the diffusion barrier action of wool fiber to the FR agents, an additional exhaustion process was employed ahead of the traditional pad-dry-cure procedure. The flame retardancy, smoke generation, thermal stability, and washing durability of the treated fabrics were discussed. The PA/TiO 2 /BTCA system endowed wool fabric with excellent flame retardancy and washing durability. The treated fabric was still able to self-extinguish after 30 washing cycles. Moreover, the FR system effectively reduced the smoke generation capacity. Thermogravimetry test shows that the FR system altered the thermal decomposition behavior of wool, and the formation of thermal protective intumescent char mainly contributed to the improved flame retardancy, revealing a significant condensed-phase FR mechanism of the treated wool. [ABSTRACT FROM AUTHOR]

In this work, a novel phosphorus-rich hybrid organic-inorganic silica coating for improving the flame retardancy of silk fabric was prepared using naturally occurring phytic acid as phosphorus precursor and catalyst for the hydrolysis of tetraethoxysilane. In addition, three silane coupling agents, namely 3-aminopropyldimethoxymethylsilane, 3-chloropropyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane, were added in the hybrid sol as cross-linkers with the aim of developing hydrophobic coatings and improving the washing durability of the treated silk fabric. The condensation degree of the hybrid sol was characterized by solid-state 29 Si nuclear magnetic resonance spectroscopy. The flammability and thermal degradation properties of the treated silk fabrics were determined in terms of limiting oxygen index, vertical burning, pyrolysis combustion flow calorimetry and thermogravimetric analyses. The surface morphology and hydrophobicity of the treated silk fabrics were evaluated by scanning electron microscopy, atomic force microscopy and water contact angle tests. The flammability tests revealed that the silicon sol could endow silk fabric with excellent flame retardancy when doped with phytic acid, and the treated silk fabrics self-extinguished immediately when the ignition source was removed. The silk fabrics treated with the modified hybrid sols exhibited hydrophobic surface and also better durability to washing. [ABSTRACT FROM AUTHOR]

This research work reported a novel approach to develop flame retardant silk fabric using naturally occurring phytic acid (PA) rich in phosphorus and TiO 2 nanoparticles through a pad-dry-cure technique. A polycarboxylic acid [1,2,3,4–butanetetracarboxylic acid (BTCA)] was employed to stabilize and improve the adhesion of TiO 2 on silk surface. The flame retardancy of the treated silk fabric was determined in terms of limiting oxygen index, vertical burning, and pyrolysis combustion flow calorimetry, and the durability of flame retardancy to washing was discussed. PA and TiO 2 were found to have a joint flame retardant effect. The combination of PA, TiO 2 and BTCA was able to endow silk fabric with excellent flame retardancy, and the good flame retardant ability was kept even after 25 times of washing. The reasons for the good washing durability of the treated silk fabric were discussed. Finally, a significant condensed-phase flame retardant mechanism of the silk fabric treated with the PA/TiO 2 /BTCA system was revealed by the analyses of thermogravimetry and pyrolysis combustion flow calorimetry. [ABSTRACT FROM AUTHOR]

• Sustainable and reactive pentaerythritol phytate ethylenediaminetetraacetic acid ester (PPEDTE) intumescent flame-retardant is synthesized. • PPEDTE coating is grafted on silk surface through covalent reaction. • PPEDTE coating has high flame retardancy and durability on silk textile. • PPEDTE coating offers an eco-friendly and durable flame-retardant approach for silk in practical applications. The exploitation of plant-derived phytic acid as effective and durable flame retardant (FR) for textiles is of great significance for developing novel and ecological functional textile products. In the present study, a reactive and phytate-based FR namely pentaerythritol phytate ethylenediaminetetraacetic ester (PPEDTE) prepared by the esterification of phytic acid, pentaerythritol and ethylenediaminetetraacetic acid was investigated as intumescent FR agent for silk fabric. The chemical structure of PPEDTE and its potential grafting mechanism on silk were studied. The thermal stability, heat and smoke suppression property, flame retardancy and washing resistance on silk fabric were studied. The deposition and covalently cross-linked PPEDTE on silk fabric enabled it to self-extinguish in vertical burning test. The coated silk fabric with an add-on of higher than 10.7% could withstand 15 washing cycles, displaying good washing durability. The intumescent FR coating remarkably decreased the release of heat and smoke of silk during burning. The coated silk had high thermal stability and left significant combustion residues after the burning tests. These results demonstrate that the synthesized PPEDTE warrant potential as efficient and reactive intumescent FR approach for silk. [Display omitted] [ABSTRACT FROM AUTHOR]

A cyclic phosphonate ester flame retardant was applied to improve the flame retardancy of poly(lactic acid) (PLA) nonwoven fabric by a pad-dry-cure technique. The effects of curing temperature and flame retardant dosage on the flammability of PLA fabric were analyzed. The burning behavior, thermal stability and flame-retardant mechanism of the flame-retardant PLA fabric were investigated by limiting oxygen index (LOI), vertical burning test, microscale combustion calorimetry (MCC), thermogravimetric (TG) analysis and scanning electron microscopy (SEM) with energy dispersive spectrum (EDS). The treated PLA fabric exhibited good flame retardancy, and its LOI was about 35%, whereas this value was 26.3% for the untreated fabric. No obvious difference of the MCC test results between the untreated and treated fabrics was found. The results from TG analyses indicated the formation of a very small amount of char during the thermal degradation process of the treated PLA fabric. The SEM-EDS analysis showed an obvious decrease in the phosphorus content of the flame retardant fabric after burning. These indicate that the gas-phase flame-retardant mechanism during combustion is dominant, and results in the good flame retardancy of the treated fabric in the presence of a very small amount of char residue. [ABSTRACT FROM AUTHOR]

Bio-based phytic acid as a nontoxic naturally occurring compound has a promising prospect in the field of the flame retardant modification of polymers because of its high phosphorus content. Bio-based and bio-degradable poly(lactic acid) has aroused considerable interest and its use is growing, but its flame retardancy needs to be improved when it is used as a flame retardant material. In this work, phytic acid was used to improve the flame retardancy of poly(lactic acid) nonwoven fabric by a pad-dry-cure technique, and the effect of phytic acid dosage on the flammability as well as the flame retardant mechanism of the treated fabric was discussed. The limiting oxygen index and vertical burning tests revealed that the treated fabric exhibited good flame retardancy. The microscale combustion calorimetry analysis showed that the treated fabric had significantly decreased heat release rate, total heat release and heat release capacity compared with the untreated fabric. The char residue formation of the treated fabric during thermal degradation, and the high phosphorus content of the burned fabric residue suggested that a significant condensed-phase mechanism contributed to the flame retardancy of the treated fabric. The flame retardant system in the present study is applicable to the poly(lactic acid) fabrics without the durability requirement. The use of phytic acid provides an opportunity for producing the flame retardant poly(lactic acid) materials using a sustainable and cleaner flame retardant agent. [ABSTRACT FROM AUTHOR]

The exploitation of resourceful plant derivatives for fabricating durable flame retardant (FR) textiles is of great interest. Herein, this study offers a novel and facile approach for developing FR wool fabric by covalently grafting bio-based ammonium phytate (APH) onto wool fibers. The potential grafting action of APH with wool fibers, the flame retardancy and washing durability, smoke and heat emission performance and FR mechanism of modified wool fabrics were explored. The modified wool fabrics could pass the vertical burning B 1 classification with a reduced char length of approximately 10.0 cm from 30.0 cm, and they also had an increased LOI of approximately 32.0% from 23.6%. The modified wool fabrics possessed increased tensile strength; they also self-extinguished during the vertical burning test after 15 washing cycles, which was attributed to the cross-linking action of APH with wool fibers. Besides, a significant reduction in smoke and heat release of wool fabric was achieved after FR grafting. The investigations on char residue confirmed the intumescent FR mechanism for APH modified wool fabrics. In general, the present study provides an industrial feasible strategy to prepare sustainable and durable FR wool fabrics using phytate derivatives. [Display omitted] • Phytate derivative APH is obtained from resourceful crops. • APH covalent grafting approach is a green, sustainable and promising technique. • APH covalent grafting approach shows high flame-retardant efficiency and durability on wool fabric. • APH covalent grafting approach offers a cleaner and industrial feasible way to minimize fire hazards of wool textile. [ABSTRACT FROM AUTHOR]

• Highly sticky functional coating is in-situ fabricated on silk surface. • The functional coating is grafted on silk surface through covalent reaction. • The functional coating has high flame retardancy and thermal stability on silk textile. • The functional coating pyrolyzes through intumescent charring mechanism. • The functional coating offers an effective and durable strategy to minimize fire hazards of silk textile. The novel strategies for fabricating durable flame retardant (FR) silk fabric with biomass phytic acid (PA) is of interest. In this study, a highly sticky coating was in-situ developed on the surface of silk fabric by adsorption of PA, 1,4-Phthalaldehyde and followed by adsorption of 3-aminopropyltriethoxysilane (KH550). The Schiff base reaction would occur between 1,4-Phthalaldehyde and silk fiber/KH550, and thus the sticky coating could be firmly grafted on silk surface. The thermal degradation, smoke and heat emission properties, flame retardancy, and washing durability of coated silk were explored. The FR coating displayed high functional efficiency and thermal stability by taking advantage of synergistic effect with phosphate groups and silica networks. The modified silk fabrics also possessed lower fire hazards as suggested by significantly reduced smoke and heat generation. The coated silk fabrics self-extinguished and obtained a char length of 13.5 cm after 20 washing cycles. The improved washing resistance should be ascribed to the covalently grafted sticky coating on silk surface. In general, this work reports a novel and feasible strategy to develop durable silk textile using bioderived PA. [Display omitted] [ABSTRACT FROM AUTHOR]

• Phytic acid and taurine are derived from different crops. • Phytate taurine salt (PTS) is successfully synthesized by ion reaction. • PTS coating displays high flame retardant efficiency and anti-dripping ability on PA6 fabric. • PTS coating mainly works in condense- and gas-phase. • PTS coating offers an effective and cleaner strategy to minimize fire hazards of PA6 textiles. Eco-friendly and sustainable flame retardant (FR) approaches derived from natural products for polyamide 6 (PA6) fabrics are of interest. Therefore, a novel biomass phytate taurine salt (PTS) was synthesized using phytic acid and taurine, and then it was coated onto PA6 fabric. The chemical structure of PTS, and the flame retardant performance and mechanism, the washing durability and physical properties of coated PA6 fabrics were explored. The damaged length of coated PA6 fabrics reduced to 12.0 cm without droplets during the vertical burning test, achieving a UL94 V-0 level. The LOI increased from 23.0% to 31.8% after PTS coating. The results of cone calorimetry showed that the pHRR of PA6-PTS sample decreased by about 11.0% with a char residue of 12.0%. The investigations on violates and char residues confirmed that PTS coating improved the flame retardancy of PA6 fabric through a combined gas-phase and condensed-phase action. In addition, the coated PA6 fabrics could still maintain V-0 level after 15 washing cycles. The tensile strength of PA6 fabrics was also slightly improved after PTS coating. In general, this work developed a durable and sustainable PTS coating with excellent flame retardancy for PA6 fabric. [Display omitted] [ABSTRACT FROM AUTHOR]

² Reactive synergistic P/Si/N-containing hybrid silica sol system is prepared. ² Hybrid silica coating has high flame retardancy and washing durability on silk textile. ² Hybrid silica coating acts as the intumescent charring flame-retardant action. ² Hybrid silica coating offers an effective and durable strategy to minimize the fire hazards of silk textile. The fabrication of phosphorus-doped sol-gel coatings for durable flame retardant (FR) modification of textiles are of interest. This study facilely synthesized a novel phosphorus-doped silica sol system using 3-aminopropyltriethoxysilane, glutaraldehyde, diethyl phosphite by simultaneous Kabachnik-Fields and sol-gel reactions. The morphology and chemical structures of hybrid silica particles were studied by TEM, FT-IR and NMR. Then, the hybrid silica sol was applied as durable FR coating to reduce the flammability of silk. The FR property and washing durability, smoke and heat generation capacity, thermal stability, and FR mechanism of coated silk fabrics were explored. The hybrid silica coating displayed good FR performance because of the synergistic action among Si, P and N. The coated fabrics self-extinguished after 25 launderings and had a high LOI value of 28.0% thanks to the covalent grafting of hybrid silica coating on silk fabrics. The explorations on silk residues confirmed the intumescent FR mechanism of coated silk. The hybrid silica coating is promising to functional as feasible and durable FR strategy for silk fabric. [Display omitted] [ABSTRACT FROM AUTHOR]

• Reactive synergistic P/N/S-containing flame retardant GASDP is prepared. • GASDP has high flame retardant ability and washing durability on silk textile. • GASDP has good smoke suppression ability on silk textile. • GASDP functions through both gas phase and condensed phase action. • GASDP offers an effective and durable strategy to minimize the fire hazards of silk textile. Improving flame retardancy of silk fabric will expand its potential application fields. Herein, a novel P/N/S-containing flame retardant (FR) named glutaraldehyde ammonium sulfamate diethyl phosphate salt (GASDP) was prepared by one-pot reaction among glutaraldehyde, ammonium sulfamate and diethyl phosphite. We further explored its potential applications in durable FR modification of silk fabric through textile exhaustion approach. The grafting mechanism, thermal stability, flame retardancy and washing durability, and FR mechanism of the coated silk fabrics were studied. GASDP coating showed high FR functional efficiency due to the synergism among P, N and S. The coated silk fabric covalently grafted by GASDP had a high LOI of about 30.0%; it still reached B 1 classification after 25 washing cycles. GASDP coating exerted good flame retardancy to silk fabric through the intumescent FR mechanism. GASDP coating displays great potential to functional as efficient and durable approach to improve flame retardancy of silk fabric. [Display omitted] [ABSTRACT FROM AUTHOR]

Nano-magnesium hydroxide (nano-Mg(OH) 2) serves as a promising flame retardant (FR) filler for plastics, but it remains a challenge to endow textiles with effective and durable FR ability. In the present work, Mg(OH) 2 nanoparticles with an average diameter of 68 nm were prepared via the double precipitation method with Tween 80 as surface modifier. Then, nano-Mg(OH) 2 was used to prepare the functional silk fabric with enhanced FR ability and smoke suppression to reduce the fire risk of silk through surface coating technique using polycarboxylic acid as cross-linker. The morphology and structure of nano-Mg(OH) 2 were studied, and the smoke/heat emission ability, FR ability and durability, and functional mechanism of the coated silk were also investigated. The nano-Mg(OH) 2 coating imparted high FR property to silk and greatly decreased the smoke/heat generation ability of silk. The coated silk fabric also displayed self-extinguishing action after 15 washing cycles, demonstrating good washing durability for the coated silk fabric. The coated silk obtained dense and continuous char residue, exhibiting excellent charring ability. This study proves that nano-Mg(OH) 2 could serve as an effective and sustainable FR agent for enhancing the fire safety of silk fabric. [Display omitted] • Nano-Mg(OH) 2 coating imparts effective flame retardancy and smoke suppression to silk textile. • Nano-Mg(OH) 2 coating has good washing durability on silk textile. • Nano-Mg(OH) 2 coating acts as char-former in condensed phase. • Nano-Mg(OH) 2 coating offers a effective and sustainable strategy to fabricate functional silk textile. [ABSTRACT FROM AUTHOR]

In this study, a reactive boron-containing flame retardant (FR) namely glycerol borate citric acid ester (GBCAE) was synthesized using boric acid, glycerol and citric acid, and was applied to improve the flame retardancy of silk fabric. The chemical structure of GBCAE and its potential cross-linking reactions with silk fiber were characterized. The thermal stability, smoke and heat suppression capacity and FR ability of the treated silk were evaluated. The treated silk fabrics with a weight gain of higher than 7.3% had self-extinguishing ability. The FR treatment endowed high thermal stability and excellent flame retardancy to silk, and suppressed the smoke and heat release of silk by nearly 50%. The treated silk could still self-extinguish after 5 washing cycles and showed good washing durability, which is attributed to the covalent cross-linking action between GBCAE and silk fiber. The char residue analyses on morphology and functional groups indicated the intumescent FR mechanism for the treated silk. The prepared GBCAE has great potential to serve as suitable alternative to toxic halogen-based agents for improving the flame retardancy of silk textiles Unlabelled Image • Reactive, halogen-free and boron-based flame retardant GBCAE is prepared. • GBCAE imparts semi-durable flame retardancy to silk textile. • GBCAE has excellent smoke and heat suppression abilities on silk textile. • GBCAE acts as an intumescent charring flame retardant system. [ABSTRACT FROM AUTHOR]

• Naturally occurring phytic acid was used to prepare phosphorus-rich hybrid silica sol. • Sodium alginate served as anti-agglomeration agent and stabilizer for the hybrid sol. • Hybrid sol coating imparted good flame retardancy to cotton textile. • Flame retardant mechanism of hybrid sol involved a condensed-phase activity. • The present hybrid sol approach is eco-friendly and sustainable. The high flammability of cellulosic materials somewhat limits their practical application. The introduction of an environmentally benign flame retardant coating for cotton fabric was achieved by hydrolyzing tetraethoxysilane and doping the silica sol with phytic acid in the presence of sodium alginate. The hybrid silica sol had high condensation degree and the modified silica particles had a spherical structure. The coated cotton fabrics with the hybrid PA/silica sol systems showed enhanced thermal stability at high temperatures, and displayed significantly suppressed heat and smoke generation ability, compared with the uncoated one. The hybrid silica sol coatings influenced the combustion performance of cotton via a charring action, and endowed the cotton fabrics with self-extinguishing ability during the vertical flammability test, demonstrating the improvement in fire resistance. The coated cotton fabrics displayed enhanced char yields, whilst maintained their texture structures after burning. Besides, the silicon- and phosphorus-containing components were also found to have a synergistic flame retardant action on cotton. [ABSTRACT FROM AUTHOR]

The durable flame-retardant functional coating of polyester/cotton (T/C) blend fabrics is both interesting and challenging. In this study, a novel in-situ polymerization strategy for phosphorus/nitrogen-based flame-retardant on T/C blend samples was developed through the polycondensation of tetramethylolphosphonium sulfate, dicyandiamide, and anionic cyclic phosphate ester. The chemical structure of the polycondensation compounds, as well as the surface morphology, combustion behavior, flame-retardant capacity, washing durability and flame-retardant mechanism of the coated T/C blend fabrics, were investigated. The coated T/C blend fabrics demonstrated excellent self-extinguishing performance, with the damaged length decreasing to as low as 8.0 cm and the LOI reaching 28 %. Moreover, the peak heat release rate of the coated T/C blend fabrics decreased by 39.7 %. The superior flame retardancy can be attributed to the enhanced dehydration and carbonization by phosphate groups in the condensed phase, as well as the quenching effect and diluting effect in the gas phase. Additionally, the coated T/C blend fabrics exhibited remarkable washing durability and still achieved self-extinguishing after 65 washing cycles, and the in-situ deposition of insoluble three-dimensional polycondensation compounds onto the T/C blend fabrics was beneficial. The flame-retardant coating had a minor impact on the whiteness, tensile strength and breathability of the T/C blend fabrics. [Display omitted] • Insoluble polycondensing compounds were in-situ deposited inside fiber interior. • The polycondensing compounds had high affinity to both cotton and polyester. • The coated T/C fabrics displayed high flame retardancy and washing durability. • The in-situ polymerization strategy was feasible and industrially applicable. [ABSTRACT FROM AUTHOR]

The incorporation of metal-organic frameworks (MOFs) on textile materials to enhance flame retardancy is of interest and challenge. In this study, an iron-rich MOF (Fe-MOF) was constructed in situ on wool fabric surface through the alternating assembly of ferric metal salt and the carboxylic acid ligand 1,3,5-benzenetricarboxylic acid. The surface morphology, flame retardancy, smoke and heat release performance, thermal stability, and flame-retardant mechanism of the Fe-MOF coated wool fabric were investigated. Square-shaped crystals were observed on the coated wool fabric, indicating successful construction of Fe-MOF on the wool surface. The coated wool fabric with an add-on of 6.8 % exhibited excellent flame retardancy, as evidenced by its self-extinguishing ability during the vertical burning test and a significantly enhanced limiting oxygen index of 32.6 %. Moreover, the coated wool fabric demonstrated a remarkable reduction in heat and smoke production of 23.8 % and 68.4 %, respectively, indicating enhanced fire safety. The analysis of char residue, including thermal stability, surface morphology, iron content, and graphitization degree, supported the formation of ferric oxides as a protective layer, contributing to the improved flame retardancy of the Fe-MOF coated wool in the condensed phase. The in situ construction of Fe-MOF on wool macromolecules offers a promising and innovative approach for developing nonhalogen and nonphosphorus flame-retardant systems. [Display omitted] ● The iron-rich metal-organic frameworks (Fe-MOF) is in situ loaded on wool surface. ● The Fe-MOF coating exhibits high flame retardancy and smoke suppression capacity. ● The Fe-MOF coating mainly functions in the condensed phase. ● The Fe-MOF coating serves as halogen-free, phosphorus-free flame-retardant system. [ABSTRACT FROM AUTHOR]

Polyurethane (PU)-coated polyester fabrics are commonly used in outdoor settings, but their flame-retardant properties are somewhat lacking. In this study, biomass phytate salt was applied to improve the flame retardancy and anti-dripping properties of PU-coated polyester fabrics. This study also explored the hydrostatic pressure, mechanical performance, heat release capacity, flame retardancy, washing durability, and mode of action of coated polyester fabrics. The polyester fabric coated with 4 % phytate salt-modified PU exhibited impressive self-extinguishing properties without any dripping. Additionally, the coated polyester fabric showed a low damaged length of 12.2 cm and a high LOI of 33.8 %, satisfying the requirements for the B 1 level. The coated polyester fabric proved to withstand 50 washing cycles, highlighting its remarkable flame retardancy efficiency and durability. It also exhibited a significant reduction in heat release, suggesting the fire safety performance. Analysis of the thermal resistance and char residue revealed a condensed flame-retardant mechanism attributed to the phytate-based system. Overall, phytate salt shows promising potential as a long-lasting flame-retardant system for outdoor PU-coated polyester fabrics. [Display omitted] • Phytate salt is derived from resourceful plants or crops. • Phytate salt has high flame retardancy and washing durability on PU-coated polyester. • Phytate salt exhibits excellent compatibility with polyurethane. • Phytate salt offers a long-lasting flame-retardant system for PU-coated outdoor polyester fabric. [ABSTRACT FROM AUTHOR]

The growing awareness of human health and environmental protection stimulates the development of more sustainable flame retardant (FR) approaches. In this study, polyaniline (PANI) with a nitrogen-containing aromatic structure was synthesized as a novel functional compound to improve the FR and UV protection performance of silk fabric. Biobased chitosan was applied to develop the PANI/chitosan coating to improve the binding capability and dispersion uniformity of PANI on the silk surface. The surface morphology, thermal resistance, heat generation capacity, flame retardancy and UV protection performance were explored. The PANI/chitosan coating with 3 wt% PANI endowed the silk fabric with effective flame retardancy. The coated silk fabric self-extinguished during vertical flammability test and possessed a decreased char length of 9.5 cm versus 30 cm of the pristine silk fabric; it could also withstand 20 launderings, showing good laundering resistance. The coated silk fabric displayed markedly decreased heat release behavior. A combined condensed phase and gas phase FR action was suggested for the PANI/chitosan coating on silk fabric. The coated silk fabric also exhibited excellent UV protection with the UPF of 50+ because of the UV-shielding of PANI. [Display omitted] • Polyaniline (PANI) is applied as halogen-/phosphorus-free flame-retardant for silk. • PANI/chitosan coating imparts effective flame-retardant and UV protection properties for silk textile. • PANI/chitosan coating works by the combined condensed and gas phase action. • PANI/chitosan coating serves as a sustainable and promising technique to minimize fire hazards of silk textile. [ABSTRACT FROM AUTHOR]

Nowadays, high value-added and multifunctional textiles have attracted widespread attention due to the changing demands of modern life. This study focused on the fabrication of silk with photochromism, flame retardancy, UV resistance and durability using riboflavin sodium phosphate (RSP) and various metal ions (Fe2+, Fe3+, Al3+, and Ti4+). Attractively, the photochromic performance was one of the most distinctive features of the modified silk, and the yellow silk fabric turned into fluorescent green under UV lamp. After a detailed comparison, it was determined that RSP/Fe3+ hybrid system was most effective in improving anti-UV performance of the silk with a high UPF of 25.8, achieving a "Good" level of UV protection. Specifically, it achieved a B 1 fire protection with a low damaged-length of 9.4 cm and a high LOI of 28.3 %. Additionally, the modified silk showed the lowest smoke density, reducing by approximately 84.1 % versus that of pristine silk. Moreover, the modified silk was able to meet the B 1 classification and the "Good" UV protection requirements even after 75 washing cycles, making it more durable than most functional textiles reported. The further analysis indicated that RSP and metal ions can synergistically enhance the condensed-phase action, thereby improving the fire resistance of silk. [Display omitted] • A sustainable multifunctional organic-inorganic hybrid system is fabricated using bio-macromolecule Vitamin-B 2 derivative. • The modified silk has superior durable flame retardancy, good UV protection and photochromism performance. • Complexing action solves the poor durability of Vitamin-B 2 derivative in the field of dyeing and finishing. • The proposed approach offers a sustainable and cleaner method for creating high value-added silk. [ABSTRACT FROM AUTHOR]

• DOPO coating is constructed by hydration reaction. • DOPO coating with a super-low p content displays good flame retardancy and anti-dripping ability on PA6 fabric. • DOPO coating effectively inhibits heat propagation and improves fire safety. • DOPO coating mainly works in gas-phase. The application of insoluble 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) to develop a durable coating for flame retardant (FR) modification of polyamide 6 (PA6) is of concern and difficult. This study found that the hydration reaction of DOPO provided the possibility of constructing a DOPO coating. Hence, DOPO compound was deposited onto PA6 fabric by dip-coating technique. Then, the impacts of DOPO coating on FR performance, anti-dripping property, smoke and heat release performance of coated PA6 fabric were systematically studied. The limiting oxygen index (LOI) of PA6 fabrics continued to increase with the increase of phosphorus content. However, the coated PA6 fabrics achieved anti-dripping property at a phosphorus content of 0.88 ∼1.75 mg/g. Besides, the heat release ability of coated PA6 reduced sharply at high phosphorus content of 1.75 mg/g, as suggested by a reduction of 20.9% and 21.8% in pHRR and THR, respectively. Moreover, DOPO coating exhibited good washing durability on PA6 fabric because of the hydrogen bond formed between DOPO and PA6, as well as the adhesion of DOPO coating. The coated PA6 fabric could still self-extinguish after 15 washing cycles. Further analysis proved that DOPO played a quenching role in the gas-phase with a weak condensed-phase action. This work points out the right direction for the future research on the preparation of FR PA6 fabric using DOPO derivatives. [Display omitted] [ABSTRACT FROM AUTHOR]

Cotton and calcium alginate (CA) fibers are both polysaccharide-based fibers, but they possess different flame retardancy. The detailed comparisons on flame retardancy and combustion behavior of polysaccharide fabrics are of interest. In this study, the difference between the fabrics made of these two fibers in the combustion process, pyrolysis products and the morphology and chemical structures of char residues were performed by vertical burning, thermal gravimetric analysis, Fourier Transform Infrared Spectrometer (FTIR) and scanning electron microscopy. Compared with cotton fabric, CA fabric had no after-flame when it was burned vertically, and the smoldering time was longer. Especially, the smoke release rate, peak heat release rate and total heat release were much lower versus cotton fabric, indicating that CA fabric had much lower fire hazards than cotton fabric. The results of thermogravimetric analysis coupled with FTIR (TG-FTIR) suggested that CA fabric exhibited a different thermal degradation pathway versus cotton fabric. Under the same quality, CA fabric produced more char residues after combustion, and chrysanthemum-like calcium oxide were generated on the surface of char residues as protective barrier, leading to the enhanced flame retardancy of CA fabric. [Display omitted] • Alginate and cotton fibers have similar polysaccharide structures but different flame retardancy and combustion behavior. • Systematic and in-depth comparative studies are carried out on combustion process/products and fabric structure of polysaccharide-based fabrics. • Calcium alginate produces chrysanthemum-like calcium oxide char structures as protective barrier. • Calcium alginate fabric has significantly decreased fire hazards versus cotton fabric. [ABSTRACT FROM AUTHOR]

[Display omitted] • Phytic acid and Thiourea are derived from plants or fungi metabolites. • Phytic acid and Thiourea both act as acid source and mutual synergists. • Intumescent flame retardant (IFR) coating displays outstanding anti-dripping and char forming ability on PA6 fabric. • IFR coating mainly works in condensed- and gas-phase. • IFR coating offers an effective and cleaner strategy to minimize fire hazards of PA6 textiles. This study focused on the construction of an eco-friendly and intumescent flame retardant (FR) coating for polyamide 6 (PA6) fabric. The intumescent FR coating, consisting of phytic acid, pentaerythritol and thiourea, was deposited onto PA6 fabric through dip-coating technique. The FR performance, anti-dripping ability, thermal stability, combustion behavior and mechanical property of the coated PA6 fabrics were explored. The severe dripping of coated PA6 fabric was totally eliminated, achieving an excellent FR performance at a low P (2.2%) and S (3.4%) content. Correspondingly, the LOI increased to 28.8% versus 23.2% of pristine one, displaying good flame retardancy. The char residue analyses confirmed the intumescent FR behavior of coated PA6 fabrics. The intumescent char layer played a major role in isolating the exchange of combustibles, oxygen and heat, leading to the significant reduction in heat release performance. The results of cone calorimetry test showed that the peak heat release rate and average effective heat of combustion of coated PA6 fabric decreased by about 36.5% and 34.4%, respectively versus pristine one. Meanwhile, the sulfur-based gases captured free radicals to interrupt the continuous combustion, leading to the significantly improved flame retardancy. Furthermore, the FR coating exerted little influence on the mechanical performance of PA6 fabric. [ABSTRACT FROM AUTHOR]