Vertical Flame Test Research Articles

Synergistic flame retardant effect of carbon nanohorns and ammonium polyphosphate as a novel flame retardant system for cotton fabrics

The development of environmentally friendly flame retardants that can achieve high efficiency for textiles at low addition levels is of great significance to human life and environmental protection. Halogen flame retardants have long dominated in flame retardant applications. However, there are increasing calls to ban its use because of the threat they pose to human health and the environment. Herein, this work investigated the potential of a novel carbonaceous nanomaterials-single-walled carbon nanohorns (SWCNHs) coating material for flame retardancy of cotton fabrics. The unique combination of SWCNHs and ammonium polyphosphate (APP) in a single halogen-free nanocoating has a synergistic effect, which endows cotton fabric with prominent fire resistance. When the addition amount of SWCNHs was 0.15 %, the limit oxygen index (LOI) could reach 27.5 ± 0.83 %, and the damage length decreased from 30 ± 0.01 % cm to 6.5 ± 0.06 % cm. SEM results showed that Cotton-APP/SWCNHs (0.15) still displayed well-preserved woven structure after the vertical flammability test. Additionally, the pHRR and THR of Cotton-APP/SWCNHs (0.15) were markedly decreased by 92.22 % and 58.44 %, respectively in the cone calorimeter test. Meanwhile, the flame retardant mechanism analysis confirmed that the incorporation of SWCNHs into the APP coatings promoted the formation of dense and stable graphitized carbon layer on the surface of the cotton fabric, and effectively prevented the generation of combustible volatiles, thus enhancing the flame retardant performance of cotton fabrics. This work provides a new insight into developing carbon nanomaterials for flame retardant polymeric materials and extending the application of SWCNHs.

NiTi-layered double hydroxide nanosheets toward high-efficiency flame retardancy and smoke suppression for silicone foam

There is a need for further enhancing fire safety of silicone foam (SiF) due to its popularization and application in aircraft and the latest generation of high-speed train. We prepared a novel NiTi-layered double hydroxide nanosheets (NiTi-LDH) by a co-precipitation method, which was used as highly effective flame-retardant and smoke-suppressor for SiF. FTIR and X-ray photoelectron spectrometerwere conducted to analyze the chemical structure of NiTi-LDH. The microstructure and crystal phase of NiTi-LDH were determined by scanning electron microscope (SEM), X-ray diffraction (XRD), and transmission electron microscopy. The results of atomic force microscope and Brunauer-Emmett-Teller analyses demonstrated that NiTi-LDH possessed an ultra-thin structure with an average thickness of 1.93 ± 0.02 nm and large specific surface areas (194.4 m2 g−1). After being evaluated by vertical flame testing (UL-94), limiting oxygen index (LOI), and cone calorimeter test, only 1.0 phr NiTi-LDH made SiF pass UL-94 V-0 rating with an increased LOI (28.7–30.3%), and greatly inhibited smoke release compared to untreated silicone foam. Meanwhile, both the maximum smoke density and smoke density rank of SiF/NiTi-LDH-1.0 are lower than those of SiF. To further understand the flame retardant action of NiTi-LDH, we used thermogravimetric analysis (TGA), XRD and FTIR to investigate its thermal decomposition behavior, the evolutions of chemical/crastal structures during heating. X-ray energy dispersive spectroscopy coupled with SEM (SEM-EDS) and TGA-FTIR were adopted to analyze the char residue and gaseous products. NiTi-LDH exhibited possible catalytic actions for high efficiency smoke suppression and flame retardancy based on char-forming and flammable volatiles inhibition in both the condensed and gaseous phase.

A Formaldehyde-free P-N Synergistic Flame Retardant Containing Phosphonate and Ammonium Phosphate for Cotton Fabrics

ABSTRACT A highly efficient and durable phosphorous–nitrogen (P-N) synergistic flame retardant containing ammonium phosphate active groups (AATMPEG) was synthesized and grafted onto cotton fabrics by P-O-C covalent bonding. In the synthesis process, the -P=O(OH)2 group on the flame retardant is esterified with ethylene glycol to reduce the influence of metal ions on the flame retardant of cotton fabric during washing. The limiting oxygen index (LOI) value of 25 wt% AATMPEG-treated cotton fabric reached 45.0% and remained at 33.0% after 50 laundering cycles (LCs). Scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), and X-ray diffraction (XRD) results showed that the flame retardant successfully penetrated the fabric without affecting its surface morphology and crystal structure. Thermogravimetry (TG), cone calorimetry, and vertical flammability test results show that AATMPEG generates phosphoric acid or polyphosphoric acid during combustion, promoting the thermal degradation and dehydration of the cotton fabric. The AATMPEG does not use formaldehyde in the synthesis process, meeting environmental requirements.

Development of Cotton Fabrics via EVA/SiO2/Al2O3 Nanocomposite Prepared by γ-Irradiation for Waterproof and Fire Retardant Applications

Development of cotton fabric (CF) properties using nanocomposites via coating method was of considerable interest for wide applications. This article aims at developing CF properties by coating treatment using ethylene–vinyl-acetate (EVA), silicon dioxide (SiO2), aluminum oxide (Al2O3) nanoparticles and γ-irradiation widely used in waterproof and flame retardant applications. EVA-based nanocomposites, EVA/SiO2, EVA/Al2O3, and EVA/SiO2/Al2O3, were synthesized by γ-irradiation and the highest gel content of 81.2–95.3% was achieved at 30 kGy. The physicochemical properties of EVA-based nanocomposites were characterized by FT-IR, XRD, DSC and SEM techniques. Usage of irradiated EVA and EVA-based nanocomposites for treatment of CF by coating technique was successfully achieved. This technique provides a simple and versatile method leading to excellent uniform and smooth surface morphology without aggregation. The weight gain, mechanical properties, thermal properties, water vapor permeability and flame-retardant properties of the modified CF were evaluated. Moreover, compared with control CF, the resistivity of water absorptivity and hydrophobic property and the thermal stability were gained. The flame retardant properties of CF samples were performed using limited oxygen index (LOI) and vertical burning flame tests. LOI percentages of CF/EVA/SiO2, CF/EVA/Al2O3 and CF/EVA/SiO2/Al2O3 increased to 25.3, 27.5, and 29.3%, respectively. Untreated CF ignited and burned rapidly after 5 s. Meanwhile, the treated CF hold flame resistance properties and the burning time prolonged to 25 s. The results of the treated CF providing revealed hydrophobic and protective capability of the fabrics from being destroyed by burning, and support their further use in waterproof and flame retardant applications of fabrics.

Assembled hybrid films based on sepiolite, phytic acid, polyaspartic acid and Fe3+ for flame-retardant cotton fabric

Abstract To impart durable flame retardant property to cotton fabric, a kind of multilayered hybrid film based on environmentally friendly phytic acid, sepiolite, polyaspartic acid, and Fe3+ were deposited on the surface of cotton fabric by layer-by-layer and spraying method to form a dense protective layer. Compared with cotton fabric, hybrid film coated cotton showed excellent flame retardant property and low fire hazard, which can be demonstrated by vertical flame test, limiting oxygen index (LOI) and cone calorimeter test. After-flame time and after-glow time of hybrid film coated cotton is 1 s and 1 s, respectively. LOI value of hybrid film coated cotton increased by 44.4% compared with control sample. Cone calorimeter test revealed a total heat release rate reduction of 52.6% and peak heat release rate reduction of 73.6% for hybrid film coated cotton fabric. This work demonstrates that the hybrid film composed of phytic acid, sepiolite, polyaspartic acid, and Fe3+ could improve the durable flame retardant property of cotton fabric.

Polymeric coacervate coating for flame retardant paper

Cellulosic paper (from wood fibers) is a highly flammable material that is used in corrugated carboard, packaging, printing, and construction. While there is significant work focused on depositing a flame retardant coating onto the individual wood pulp fibers, there are very few studies that apply flame retardant coatings to already-cast paper. In an effort to improve the flame retardant properties of paper, a polymer-dense coacervate composed of polyethylenimine (PEI) and poly(sodium phosphate) (PSP) was deposited in a single step and subsequently crosslinked with glutaraldehyde. In a vertical flame test, the crosslinked PEI/PSP coacervate-coated paper achieves self-extinguishing behavior, and an average char length of 3.4 in, with only a 35% weight gain. Additionally, the crosslinked coating retains its flame retardant properties after water immersion and conditioning tests. This coacervate system is the first polymeric coating to be successfully deposited onto commercially available cellulosic paper for the purpose of flame retardancy.

A flame retardant fabric nanocoating based on nanocarbon black particles@polymer composite and its fire-alarm application

• Carbon black nanoparticles with core-shell structure (CB@KF) were prepared. • CB@KF can endow cotton fabric with great flame retardancy and fire-warning property. • Modified cotton fabric has great mechanical property and flexibility. • The mechanism of flame retardant and fire-warning were illustrated. Facile fabrication of fire-warning sensors with low-cost and high-strength has always been a considerable challenge for materials scientists. Herein, Carbon black (CB) nanoparticles with core-shell structure (denoted as CB@KF) were prepared by in-situ polymerization. And a novel fire-warning sensor (denoted as CB@KF-CF) with temperature sensing, fire-warning, flexibility and high strength was fabricated by coating a flame retardant coating, which consists of PVA, CB@KF, and Carbon nanotubes (CNT) on cotton fabric. Benefiting from the flame retardancy and carbonization performance of CB@KF, CB@KF-CF possessed much better flame retardancy and fire-warning properties. Especially, CB@KF-CF exhibited a shorter alarm time to abnormal high temperature (350 °C) and fire, which can warn at 8 s and 4 s respectively. Meanwhile, the char length of CB@KF-CF was 7.8 cm after the Vertical flame test (VFT) and the Total heat release rate (THR) of CB@KF-CF was also reduced by more than 50%. Ultimately, the formation mechanism of the dense char layer and the conductive paths were also illustrated. These results show that the preparation of fire-warning sensor described in this paper has broad application prospects.

Influence of hydroxyl-terminated phosphoramidates on the flame retardancy of microfiber synthetic leather

As the ideal substitute for natural leather, microfiber synthetic leather (MSL) possesses excellent mechanical/chemical properties and have been commonly applied in our daily life. However, the flammability strictly limits its application in the field with high fire-safety requirement. Herein, three classical phosphorus-containing compounds with terminated hydroxyl groups, named as DTP-OH (dimethyl phosphate derivative), DPPC-OH (cyclic phosphate derivative) and DOPO-OH (DOPO derivative), were synthesized and served as the flame-retardant coating on microfiber synthetic leather. The influence of different phosphoramidates on the flame-retardant performance of microfiber synthetic leather was investigated by vertical flammability test (VFT) and limited oxygen index (LOI). Among them, DPPC-OH and DOPO-OH had better flame retardant efficiency with the comparable loadings. The LOI value increased from 18.1% to 25.7% and 26.1% respectively after coating with DPPC-OH and DOPO-OH, and they successfully passed the vertical burning test. Meanwhile, the thermal degradation and combustion behavior were also analyzed to further confirm the flame-retardant mechanism. It was found that these hydroxyl-terminated phosphoramidates can efficiently improve the char-forming ability of microfiber synthetic leather and the peak heat release rate (PHRR) reduced by 37% for the DPPC-OH modified microfiber synthetic leather. This work indicates that cyclic phosphate and DOPO derivatives has a good application prospect in the preparation of fire-safety microfiber synthetic leather.

Preparation of an electrically conductive, flame-retardant, and superhydrophobic recycled paper

Improving the performance of recycled paper (R paper) can broaden its applicability in different fields and is conducive to saving resources. Herein, we report a simple method to prepare R paper using waste-print-paper pulp mixed with ketjenblack and ammonium polyphosphate followed by modification with polydimethylsiloxane. The R paper demonstrated good electrical conductivity of 14.83 S/m. Water contact angle (WCA) and sliding angle (SA) were used to assess the wettability of the prepared R paper. The WCA and SA of the R paper reached 152 ± 2° and 3.5°, respectively, thereby indicating excellent superhydrophobicity. Vertical flame tests and thermogravimetric analysis proved that the flame retardancy of the R paper was superior to that of the waste-print paper. These results suggested that the R paper with conductive, flame-retardant, and superhydrophobic properties can be obtained by incorporating specific fillers into waste-print paper, thereby increasing the potential for the application of R paper.

Halogen‐Free Coatings Combined with the Synergistic Effect of Phytic Acid and Montmorillonite for Fire Safety Flexible Polyurethane Foam

AbstractTo overcome defects of some synthetic flame retardants, water‐based coatings using ammonium phytate (AP) and montmorillonite (MMT) as low‐cost renewable materials are fabricated to improve the flame retardancy of flexible polyurethane foam (FPUF). The flame‐retardant FPUF with uniform coatings can avoid melt‐dripping during the vertical flame test (UL‐94), and AP5MMT5/FPUF (flame‐retardant FPUF with the 5:5 weight ratio of AP:MMT in the solutions) reaches a UL‐94 V‐0 rating. A remarkable conclusion can be found that AP and MMT present a synergistic effect under the appropriate proportions. The thermal stabilities of flame retardant FPUF at higher temperature zones are enhanced. Furthermore, flame‐retardant samples prevent the flame from spreading on the surface of FPUF. Cone calorimetry results reveal 67% (AP5MMT5/FPUF) reduction of peak heat release rate relative to pure FPUF, and the release of toxic smoke significantly decreases. AP can catalyze the carbonation of FPUF, and MMT is heated and dehydrated to form a silicon‐containing barrier layer. AP/MMT coatings can form stable and solid physical char layers, which act as a barrier to heat and oxygen exchange, and the release of volatiles is delayed and inhibited. This work introduces a green plan for improving the fire safety of FPUF.

Moisture barrier layer with supplemental chemical and biological protective functionality for firefighting clothing applications

One of the primary constituent layers of fire protective clothing is a flame-retardant, waterproof and breathable moisture barrier, which permits the outward transfer of perspiration from the firefighter’s body, while barring the inward entry of water. The introduction of a chemical and biological resistant functionality can greatly enhance the overall applicability of fire protective clothing. In the present work, a chemical & biological resistant waterproof breathable flame retardant moisture barrier fabric was prepared by laminating a biaxially stretched microporous expanded polytetraflouroethylene (ePTFE) membrane with Activated Carbon Fabric using a hot melt reactive breathable polyurethane adhesive. The developed laminate was found to exhibit an excellent balance of waterproofness (23 kPa) and breathability, which was quantified in terms of water vapour transmission rate (WVTR) and water vapour resistance (Ret). High values of WVTR, 1.1025 × 104 ± 9.8×101 g/m2/day complimented with exceptionally low values of Ret, 2.9 m2Pa/W are indicative of its high degree of breathability. Vertical flammability tests clearly revealed the exceptional flame resistance offered by the laminate, where after-flame, after-glow or melt-dripping was not observed and the char length was ∼4.2 cm. Further, the laminate exhibited requisite degree of protection against biological and chemical warfare (CW) agent with no breakthrough of the CW agent being perceived within the time frame of 24 h. The excellent combination of flame retardancy, breathability, waterproofness, chemical and biological protection, bestows the laminate excellent potential for usage as moisture barrier in fire protective clothing applications.

Bio-Based Flame-Retardant Coatings Based on the Synergistic Combination of Tannic Acid and Phytic Acid for Nylon-Cotton Blends.

Natural and synthetic polymeric fibers are used extensively in making fabrics for a variety of civilian and military applications. Due to the durability and comfort, nyco, a 50-50% blend of nylon 66 and cotton, is used as the material of choice in many applications including military uniforms. This fabric is flammable due to the presence of cotton and nylon but has good mechanical properties and is comfortable to wear. Here, we report a novel surface functionalization method that utilizes a synergistic combination of bio-based materials, tannic acid (TA) and phytic acid (PA), to impart flame-retardant (FR) properties to the nyco fabric. TA and PA were sequentially attached to nylon and cotton fibers through hydrogen bonding interactions and phosphorylation, respectively. The surface functionalization of the treated fabrics was confirmed using Fourier-transform infrared spectroscopy. Thermogravimetric analysis, microscale combustion calorimetry, cone calorimetry, and vertical flame testing were employed to study the effect of the functionalization on the thermal stability and flammability of the nyco fabric. Though reasonable durable functionalization is observed from elemental analysis, it is not enough to impart wash-durable FR treatment. These results indicate that flame retardancy is enabled through the enhanced char formation provided by the combination of TA and PA. The TA-PA system applied to nyco shows great promise as a bio-based FR system. This study for the first time also provides evidence for the selectivity of TA in imparting FR characteristics for nylon and PA in imparting FR properties for cotton. The combination of TA and PA provides promising FR characteristics to nyco.

New flame retardant epoxy resins based on cyclophosphazene-derived curing agents

To obtain high-efficiency flame retardancy of epoxy resins, a cyclophosphazene derivative tri-(o-henylenediamino)cyclotriphosphazene (3ACP) was successfully synthesized and used as a curing agent for the thermosetting of an epoxy resin system. The flame retardant properties, thermal stability, and pyrolysis mechanism of the resultant thermosets were investigated in detail. The experiments indicated that the synthesized thermoset achieved a UL-94 V-0 rate under a vertical burning test as well as a limiting oxygen index (LOI) of 29.2%, which was able to reach V-0 even when a small amount of 3ACP was incorporated. Scanning electronic microscopic observation demonstrated that the char residue of the thermosets was extremely expanded after the vertical flame test. Thermal analysis showed that the samples had a lower initial decomposition temperature when 3ACP was introduced into the epoxy resin systems. This indicates that the carbonization ability of the thermosets was significantly improved at elevated temperatures. In addition, the incorporation of 3ACP can effectively suppress the release of combustible gases during the pyrolysis process, and the decomposition of E-44/DDS-3ACP curing systems also promotes the formation of polyphosphoramides charred layer in the condensed phase. The investigation on the chemical structures of both the gaseous and condensed phase pyrolysis process confirmed the flame-retardant mechanism of the 3ACP-cured epoxy resins. Therefore, the nonflammable halogen-free epoxy resin developed in this study has potential applications in electric and electronic fields for environment protection and human health.

A biological reactive flame retardant for flame retardant modification of cotton fabric

A novel, high-efficiency, bio-based flame retardant ammonium salt of arginine hexamethylenephosphonic acid (AAHMPA) for cotton fabric was synthesized and grafted onto the cotton fabric by P–O–C and C–O–C covalent bonds. The flame retardancy and durability of treated cotton were improved obviously. The limiting oxygen index (LOI) value of 35 wt% AAHMPA-treated cotton reached 45.1%, and after 50 laundering cycles (LCs), the LOI value remained at 28.6%. The cone calorimeter, thermogravimetric and vertical flammability test indicated that treated cotton decomposed into phosphoric acid or polyphosphoric acid during combustion, which promoted the thermal degradation and charring of cotton fabrics and hindered the spread of flames. The mechanical properties of treated cotton fibers were slightly reduced. These results confirmed that AAHMPA treated cotton obtained excellent flame retardancy and high durability. • Flame-retardant cotton fabric was prepared by surface modification. • The treated cotton fabric has excellently durable flame retardant. • The flame retardant can form P–O–C and C–O–C covalent bonds with cotton fibers. • The raw materials of flame retardant are naturally-abundant. • Flame retardants will not produce harmful substances during use.

One Pot Facile Synthesis of Self-extinguishable Metal Based Flame Retardant for Cotton Fabric

ABSTRACT An efficient metal-based flame-retardant was prepared for cotton fabric (CF) by a convenient pad-dry-cure method, which involves the consecutive deposition of intumescent containing different combination of ammonium polyphosphate, melamine, pentaerythritol with Copper and Zinc metal ions. We studied different properties like thermal, mechanical, flammability, and laundering durability of treated CF samples. The intumescent-coated CF shows remarkable high-efficiency flame-retardant properties: (1) a self-extinguishing property (5 s) without lateral spreading of flame during the vertical flame test with a lower smoke release character; (2) the limiting oxygen index (LOI) values of coated CF are improved with increasing add-on level. The Zn-based samples exhibited a high limiting oxygen index value of 36%. Consequently, the resultant fabrics were observed to show great flame retardancy with high thermal stability as 35% of char yield at 600°C. The durability of modified cotton was tested after five laundering cycles, which showed that the coating maintains 84% of its initial mass. It is reported that in addition to durable flame retardancy, the mechanical properties of cotton were also enhanced. The present work provides eco-friendly one pot facile synthesis of intumescent-based flame retardant for CF which may be used in numerous applications. Abbreviations: ammonium polyphosphate; PER: pentaerythritol; MEL: melamine; LOI: limiting oxygen index; TGA: thermogravimetric analysis; DTG: derivative thermogravimetry; GSM: gram per square meter; FR: flame retardant; CP: plain cotton fabric; CT: twill cotton fabric; CF: cotton fabric; Int: intumescent; FTIR: Fourier Transformation Infrared; BEL: burn entire length; DNI: did not ignite; SE: self-extinguish; HGMs: hollow glass microspheres; CH/PA/Ba/PA: Chitosan/ Phytic Acid/Barium/Phytic Acid; DPPMA: diphenylphosphinic acid with melamine; PBS/30PA-GU: poly(butylene succinate/30 phytic acid-guanosine; PET: polyethyleneimine; Tri-HTAC: 2,4,6-tri[(2-hydroxy-3-trimethyl-ammonium)propyl]-1,3,5-triazine chloride; TA/B@PDA: tannic acid/Borax@polydopamine; P10H5: 5wt% HCCP(Hexachlorocyclotriphosphazene). ammonium polyphosphate; PER: pentaerythritol; MEL: melamine; LOI: limiting oxygen index; TGA: thermogravimetric analysis; DTG: derivative thermogravimetry; GSM: gram per square meter; FR: flame retardant; CP: plain cotton fabric; CT: twill cotton fabric; CF: cotton fabric; Int: intumescent; FTIR: Fourier Transformation Infrared; BEL: burn entire length; DNI: did not ignite; SE: self-extinguish; HGMs: hollow glass microspheres; CH/PA/Ba/PA: Chitosan/ Phytic Acid/Barium/Phytic Acid; DPPMA: diphenylphosphinic acid with melamine; PBS/30PA-GU: poly(butylene succinate/30 phytic acid-guanosine; PET: polyethyleneimine; Tri-HTAC: 2,4,6-tri[(2-hydroxy-3-trimethyl-ammonium)propyl]-1,3,5-triazine chloride; TA/B@PDA: tannic acid/Borax@polydopamine; P10H5: 5wt% HCCP(Hexachlorocyclotriphosphazene).

Properties of flame-retardant cotton fabrics: Combustion behavior, thermal stability and mechanism of Si/P/N synergistic effect

A novel silicon, phosphorus and nitrogen synergistic flame retardant, aminoethylpiperazine phosphoric acid methyl ester modified siloxane (EPSO-P) was synthesized, the structure of EPSO-P was confirmed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The limiting oxygen index (LOI) value of cotton fabrics treated by EPSO-P increased to 31.4 %, and passed the vertical flammability test (VFT) with a residual char length of 6.3 cm. The thermal stability of samples is obviously improved after processing, and the char residue maintained 43 % at 700 °C in nitrogen atmosphere. The burning behavior of cotton fabrics showed that the peak heat release rate decreased from 232.1 kW/m2 to 74.5 kW/m2, and the total heat release decreased from 6.3 MJ/m2 to 2.8 MJ/m2 after flame retardant treatment. The flame retardant mechanism of the samples was analyzed by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and thermogravimetric analysis coupled with fourier transform infrared analysis (TG-FTIR). The results indicated that the EPSO-P can prevent the fabrics from burning in gas phase and condensed phase. This work proved that EPSO-P is enlightening for the production of flame retardant cotton fabrics with considerable properties.

Intumescent-Grafted Bamboo Charcoal: A Natural Nontoxic Fire-Retardant Filler for Polylactic Acid (PLA) Composites.

In this work, an alternative flame-retardant filler based on phosphate- and urea-grafted bamboo charcoal (BC-m) at 10–30 wt % addition was aimed at improving the flame retardancy of polylactic acid (PLA) composites. The filler caused only a small reduction in strength properties but a slight increase in the modulus of elasticity of PLA composites. BC-m significantly improved the flame-retardant performance compared with pure BC. The limiting oxygen index (LOI) was 28.0 vol % when 10 wt % of BC-m was added, and 32.1 vol % for 30 wt % addition, which was much greater than the value of 22.5 vol % for 30 wt % pure BC. Unlike pure BC, adding BC-m at 20 wt % or more gave a UL-94 vertical flame test rating of V-0 with significantly reduced melt dripping. The peak heat release rate (pHRR) and total heat release (THR) of BC-m/PLA composites decreased by more than 50% compared with pure PLA, and the values for 20% BC-m were significantly less than that for 25% BC addition. The grafted biochar-based system provides an effective flame retardancy effect by a condensed-phase protective barrier through the rapid formation of a dense, honeycomb-like cross-linked carbonized char layer. The results suggest a promising route to enhancing the flame-retardant properties of biodegradable polymer composites using nontoxic, more environmentally friendly grafted biochar.

INVESTIGATION OF SYNTHESIS PARAMETERS OF ANTIMONY FLUOROBORATE AND ITS USABILITY AS A FLAME RETARDANT FOR CELLULOSIC FABRICS

In this study, the synthesis parameters of antimony fluoroborate, one of the metal fluoroborates, from antimony trioxide and fluoroboric acid by the wet method, and its usability as flame retardant for cellulosic fabrics have been investigated. The maximum reaction yield was determined depending on the mole ratio of reactants, temperature and stirring speed. The characterization of the product was performed by XRD and FTIR analyses. Antimony fluoroborate was produced with 94% yield at a mole ratio of reactants (nHBF4/nSb2O3) of 6:1, at 70 °C and 300 rpm. The thermal behaviors of untreated fabric and fabric impregnated with antimony fluoroborate solution were analyzed by TGA. The flame retardancy performance of antimony fluoroborate for cellulosic fabrics was determined by the vertical flame test and the limiting oxygen index (LOI) test methods. The results show that impregnating cellulosic fabrics with antimony fluoroborate enhances their thermal stability and flame retardancy.

A STUDY ON ENHANCING THE FLAME RETARDANCY OF POLYPROPYLENE YARN WITH BORON COMPOUNDS

Functional properties such as; water resistance, flame retardancy, antibacterial efficiency etc. are required from textile products. One of the most commonly demanded products among functional textile products is the flame-retardant textiles. In this study, it is aimed to produce polypropylene filament yarn with permanent flame retardancy functionality by adding boron compound, which is Anhydrous disodium tetraborate powder (particle size < 38 micron), to the fiber structure during melt spinning process. In this study two different yarn samples are produced with anhydrous disodium tetraborate content by mass ratios of 2% and 5%. A control polypropylene filament yarn sample is also produced with no additive. By this way, three samples are produced by a conventional BCF polypropylene melt spinning machine with the same production parameters. Then, three knitted fabric samples were produced flat knitting machine. Limiting Oxygen Index (LOI) and vertical flammability tests were applied to the samples. According to results an important level of increase for LOI value is obtained with the sample which has 2% boron compound additive. Nevertheless, there is not a consistent effect of increasing boron content in yarn structure for LOI value. The reason of this situation may be resulted due to the uneven distribution of the boron compound in the yarn structure because of the particle size.

Smoldering suppression and synergistic effect of alginate fiber‐based composite paper by flame‐retardant lyocell fiber

AbstractThe application of traditional cellulosic paper is limited because of its flammability, so it is necessary to explore new materials that can be used in the field of flame‐retardant paper. Based on the synergistic effect between fibers, flame‐retardant lyocell (FRL) and calcium alginate (FRL/Ca‐Alg) composite paper is prepared by a simple but efficient method. The thermal degradation process of the composite paper is analyzed by thermogravimetric (TG) and TG analysis coupled with Fourier transform infrared, the flame retardancy of the composite paper is analyzed by vertical flammability (VF) tests, limiting oxygen index test and cone calorimetry test, and the morphology of the residue after VF tests is observed by scanning electron microscopy. It is found that, the Ca‐Alg releases a large amount of CO2 before ignited, which delayed the ignited time of the composite paper; FRL reduces the effective combustion heat of composite paper during combustion, and the compact char formed by FRL effectively inhibits the smoldering of Ca‐Alg in the end stage of combustion. Based on these, the synergistic flame‐retardant effect of composite paper is proposed.