Flame-retardant Viscose Research Articles

The synergistic effect of graphene oxide and flame-retardant fabrics

This study aims to explore the synergistic flame retardancy mechanism of graphene oxide (GO) and flame-retardant textiles. The flame-retardant properties of fabrics were evaluated through combustion behaviors test, scanning electron microscope (SEM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), as well as Attenuated Total Reflection Flourier Transformed Infrared Spectroscopy (FTIR-ATR). The result of this study demonstrated that the addition of GO enhanced the fabric’s flame-retardant performance. GO’s excellent thermal conductivity synergizes with phosphazene derivatives promoting denser carbon layers formation. The dense char layer can isolate heat and oxygen to achieve the flame-retardant effects. Flame-retardant viscose fibers (FRVF)/flame-retardant polyacrylonitrile (FRPAN)/GO fabrics formed a denser carbon layer during burning, which provided heat insulation and oxygen barrier functions. The surface of FRVF/Cotton/GO fabrics had a porous carbon layer structure that isolated oxygen and prevented heat transfer. Adding GO improved the flame-retardant properties of both fabrics, although their flame-retardant mechanisms were different. GO has promising potential as a flame retarding nano-additive in composite fabrics.

The fabrication of flame-retardant viscose fabrics with phytic acid-based flame retardants: Balancing efficient flame retardancy and tensile strength

Viscose fabrics have been widely used in various applications, but their potential fire hazard has been a concern. To address this issue, improving the flame retardancy of viscose fabrics has become a significant priority. Phytic acid (PA) and xylitol were used to create a novel flame retardant, PAXY. PAXY was finished on viscose fabrics by pad-dry-curing process, and the performance of coated viscose fabrics was investigated. The results showed that the limiting oxygen index value of PAXY13–100 (fabrics finished with a 100 g/L flame-retardant solution and the flame retardant synthesized by a 1: 3 M ratio of PA to xylitol) reached 32.8 % and the heat release rate value was decreased by 77 %. Based on the findings from the analysis of both the gas phase and condensed phase products, PAXY promoted the dehydration of viscose fabrics to produce a denser char layer, which inhibited the production of flammable gases. Surprisingly, the breaking force retention of PAXY13–100 reached 90 % in warp and 114 % in weft. Compared with that of 100 g/L PA-treated fabrics, the breaking force of PAXY13–100 increased by nearly 400 %. This work provides a new strategy for PA-based flame-retardant finishing with the synergy of flame retardancy and breaking force retention.

Preparation and properties of the flame-retardant viscose fibers based on the intumescent dithiocarboxyphosphate microcapsules

Preparation and properties of the flame-retardant viscose fibers based on the intumescent dithiocarboxyphosphate microcapsules

Enhancing anti‐meltdrop and smoke suppression properties of flame retardant poly(ethylene terephthalate) fabric by fiber‐blending method

AbstractFlame retardant poly(ethylene terephthalate) (FRPET) fabrics are widely used in daily life. However, the meltdrop and visible smoke produced during combustion significantly limit its further application. This study proposes a simple but effective method of fiber‐blending to improve the above shortcomings. On the basis of synergistic flame retardancy of nitrogen and phosphorus, the FRPET was blended with flame retardant viscose (FRV) and intrinsic nitrogen‐containing flame retardant fibers (NIFRFs), to prepare the binary and ternary blended FRPET samples labeled as NIFRF/FRPET and FRV/NIFRF/FRPET, respectively. The limiting oxygen index and cone calorimeter test show that the ternary‐blending could effectively suppress the combustion of FRPET fiber composite. The smoke density test and UL‐94 vertical combustion test indicate that ternary‐blending could better improve the meltdrop characteristics and smoke suppression property than binary‐blending. Among all samples, FRV/PMIA/FRPET (1:4:5) owns the highest LOI of 32.6% and lowest smoke density of 61.37. The investigation of residual char utilizing scanning electron microscopy, the X‐ray photoelectron spectroscopy and the Laser Raman spectroscopy demonstrates that the FRPET meltdrop would adhere to the surface of component fibers to avoid droplets. Besides, fiber‐blending could increase the yield and degree of graphitization of residual char, which is conducive to improving samples' flame retardancy through the condensed phase. This work may provide a workable strategy to expand the application areas of FRPET fabrics.

Thermal, mechanical and comfort performance of various modacrylic fibre blended fabric

In this study, various blended fabrics of modacrylic fibre with flame retardant (FR) viscose, and Nylon 66 have been manufactured and studied for their thermal, mechanical and comfort properties for workers of oil & gas industry. The ring spinning system is used to manufacture three sets of yarns. In the first set, three yarns are produced using only modacrylic, only FR viscose, and only Nylon 66 fibres. The second set of yarns is made using blends of FR viscose and modacrylic. These fibres are blended in three different ratios of 30:70, 50:50 and 70:30 for making yarns. The third set is made out of tertiary blends of FR viscose, nylon 66 and modacrylic. These are blended in two different ratios of 30:20:50 and 50:20:30 respectively. Fabric samples have been produced out of these yarns and evaluated for their flame, thermal and mechanical properties after 5 and 50 washes. The radiant heat transfer index and convective heat transfer index of blends of modacrylic fibre are found in the range 12 - 13.5 s and 5.0 - 5.7 s respectively. Multivariate test analysis has been applied to find out the effect of different fibre blends on various flame and thermal properties. The study shows that flame and thermal resistant properties are influenced by fibre blending ratio.

Preparation of flame retardant viscose fibers by supramolecular self‐assembly

Preparation of flame retardant viscose fibers by supramolecular self‐assembly

Flammability and Thermoregulation Properties of Knitted Fabrics as a Potential Candidate for Protective Undergarments.

The most important functional purpose of knitted fabrics used for the protective non-flammable underwear worn in contact with the skin is to ensure wearing comfort by creating and maintaining a constant and pleasant microclimate at the skin surface independently from the environmental conditions. Protective non-flammable underwear may be used by firefighters or sportsmen, e.g., racing (Formula) sportsmen, where a risk of burn injuries (when the car is on fire after a car crash) is present. In order to investigate the flammability and thermal comfort properties of two-layer knitted fabrics, two groups of aramids and flame-retardant (FR) viscose fiber fabrics of different combined patterns and surface structures (porosity and flatness) were designed and manufactured for this research. Aramid fiber spun yarns (METAFINE.X.95®) formed the inner layer (contacting with human skin) of fabrics and aramid/viscose FR fiber spun yarns (METALEN®) formed the outer layer. For the evaluation of the functional characteristics of the manufactured fabrics, the flammability and thermoregulating properties, such as liquid moisture management, water vapor and air permeability, and thermal resistance were investigated. The results show that all tested fabrics are non-flammable, breathable, permeable to air, and can be assigned to moisture management fabrics. Their obtained overall moisture management capacity (OMMC) values are in the range 0.59–0.88. The knitted fabrics with an embossed porous surface to skin had a higher OMMC (0.75–0.88). The thermoregulation comfort properties were mostly influenced by the structure of the fabrics, while the burning behavior was found to be independent from the structure, and the non-flammability properties were imparted by the fiber content of the knits.

Synergistic flame retardant weft-knitted alginate/viscose fabrics with MXene coating for multifunctional wearable heaters

Flexible wearable heaters have received increasing attention in energy-saving, diverse personal thermal requirements, and healthcare management. Herein, considering the fire safety application of wearable heaters, the biodegradable alginate fibers and flame retardant (FR) viscose fibers are attempted to mix and weft-knit into the fabric, which interestingly exhibits synergetic flame retardancy with low afterflame time, afterglow time, and peak heat release rate. Further, assisted by the highly conductive Ti3C2Tx (MXene) nanosheets on the surface of the fabric and the periodic nested loops of the knitted fabric, the integrated fabrics possess excellent electrical performance (2Ω sq−1) with the MXene content of 9.13 wt%, electromagnetic interference (EMI) shielding efficiency of 55 dB in the X band, preferable Joule heating performance under safe low voltage (123 °C at 3.5 V) and sunlight/far-infrared heating performance. The superior flame retardancy and multifunctional properties arose from the high-temperature induced well-constructed char layer, unique functionality of interconnected MXene network and multiple scattering of light or wave. Combined with the superior flame retardancy and multifunctional properties, the weft-knitted alginate/FR viscose fabrics with MXene coating become the ideal candidate materials in the fields of wearable heaters with high safety.

Eco-friendly coating based on an intumescent flame-retardant system for viscose fabrics with multi-function properties: Flame retardancy, smoke suppression, and antibacterial properties

Ammonium phytate and chitosan were chosen as eco-friendly flame retardants to improve the flame retardancy and antibacterial properties of viscose fabrics. The flame-retardant viscose fabrics exhibited sharp improvements in thermal stability at the higher temperature zone, and 2BLviscose retained 39.0% char residues at 700 °C. 2BL/viscose obtained a limiting oxygen index value of 29% and self-extinguished in the vertical flame test. The fire behaviors of the flame-retardant viscose fabrics were also enhanced; even the addition of CS decreased the total smoke production value from 0.6 to 0.3 m2. Flame-retardant viscose fabrics released less flammable substances and more H2O, resulting in combustion choking. Meanwhile, the flame-retardant samples formed stable char residues, which were mainly constituted by graphite. Meanwhile, the viscose fabrics coated with CS/AP exhibited excellent antimicrobial properties, and 2BL/viscose obtained a 99.99% antibacterial rate for both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli).

Preparation and mechanism of phosphoramidate-based sol-gel coating for flame-retardant viscose fabric

To prepare efficiently flame-retardant sol-gel coating for viscose fabric, a novel phosphoramidate siloxane (TSPDP) was synthesized and fire-safety viscose fabrics were prepared via sol-gel method with different contents of TSPDP. When the weight gain (WG) was more than 13%, higher limiting oxygen index (LOI) value was obtained and the coated viscose fabric passed the vertical flammability test with self-extinguishing behavior. A sharp reduction of more than 42% in peak of heat release rate (pHRR) was discovered for coated viscose fabric in contrast with pure sample. The good flame retardancy of TSPDP-coated viscose fabric was due to the co-presence of P, N and Si elements, which can form a char layer barrier in condensed phase during the combustion and inhibit the release of flammable volatiles in high temperature. Moreover, this coating had few effects on the tensile strength of viscose fabric.

Synergistic effect between flame retardant viscose and nitrogen-containing intrinsic flame-retardant fibers

A simple but effective method was proposed to promote the flame retardancy of blended fibers based on the synergistic effect between flame retardant fibers. The flame retardant viscose (FRV) is blended with three kinds of nitrogen-containing intrinsic flame-retardant fibers (NIFRFs), respectively. The limiting oxygen index, cone calorimeter test, thermogravimetric analysis coupled with Fourier transform infrared, scanning electron microscopy, X-ray photoelectron spectroscopy, and the laser Raman spectroscopy are used to have a comprehensive investigation on the flame retardant properties and mechanism of blended fibers. Results show that there is an obvious synergistic effect between FRV and NIFRFs. However, it is found that the improvements in flame retardancy of fiber blends have no direct relationship with the nitrogen content of NIFRFs. The difference of thermal degradation temperature (Tdmax) has more influence on the synergistic flame retardancy of the two fibers. The closer the Tdmax of FRV and NIFRF is, the more obvious the synergistic effect between blended fibers is. The residual char of blended fibers are all more compact and integrated than those of pure fibers. The FRV/poly(m-phenylene isophthalamide) (PMIA) 20/80 has the highest LOI of 47.5%, showing the best flame retardancy.

Preparation and characterization of collagencoclotriphosphazene and its action in flame-retardant viscose fiber

In order to develop a flame retardant using the phosphazene derivative of a natural polymer, hexachlorocyclotriphosphazene and collagen were used as the raw materials to synthesize collagencoclotriphosphazene. The Fourier transform infrared results indicate that flame retardant collagencoclotriphosphazene(CGCP) was successfully synthesized. Thermal properties of CGCP were evaluated using thermogravimetry. The thermal analysis shows that the introduction of phosphazene into collagen lowered the primary decomposition temperature, increased the decomposition rate, and caused less weight loss. The viscose fibers blended by CGCP were prepared by the wet spinning method, and the properties of the fiber were investigated. Limiting oxygen index of the flame-retardant fiber containing 12% CGCP was 28.3%, which increased greatly comparing to the fiber sample without CGCP and just decreased slightly to 27.6% after 30 washing cycles. The thermal analysis shows that the introduction of CGCP increased the decomposition rate of viscose fiber at a lower temperature, and caused less weight loss. After burning, the scanning electron microscopy image showed an inflated carbonized coat on the fiber surface. The effect of CGCP on the mechanical properties of the fibers was insignificant. CGCP was compatible with cellulose, and the flame retardancy of the viscose fiber was significantly improved. Due to the introduction of CGCP, moisture regain of the fiber is a little higher than that of viscose fiber.

Characterization of flame-retardant performance of polyester/flame-retardant viscose blended yarn

In this paper, a flame-retardant blend yarn was designed with flame-retardant viscose fiber and polyester. Flame-retardant viscose fiber was blended with polyester by core-spun method. Polyester was set as a core and the flame-retardant viscose fiber was set as a sheath to change the flame retardancy and disadvantage of moisture permeability. After the flame-retardant viscose fiber was spun into roving, polyester was added in spun yarn. The core yarn samples with different ratios were prepared by adjusting the amount of flame-retardant viscose fiber. The flame retardancy of core-spun yarn was evaluated by limiting oxygen index, scanning electron microscope, thermogravimetric analysis, and thermogravimetric/Fourier transform infrared techniques. Limiting oxygen index of the yarn with 50% flame-retardant viscose fiber and 50% polyester was 27.6% and just decreased slightly to 27.1% after 30 washing cycles. Polyester begins to melt from inside core-spun yarn after heating and the molten polyester flows to outer layer of yarns by the diversion effect of higher temperature. Then it was carbonized by the polymetaphosphate which was generated by the flame-retardant viscose fiber. In thermal processes, the major product of thermal decomposition was CO2.

Efficient suppression of flammability in flame retardant viscose fiber through incorporating with alginate fiber

The flame retardancy of flame retardant viscose (FRV) fiber can be significantly further improved by simple blending with alginate (A) fiber, even though with the content of 10 wt%. Cone calorimeter results showed that longer time to ignition (TTI), lower peak heat release rate (PHRR) and total heat release (THR) can be achieved in FRV after mixing with A. For example, the TTI of FRV can be raised from 10 s to 41 s after blended with only 10 wt% A. The mechanism of the effective suppression of flammability mentioned above was put forward by thermogravimetric analysis coupled with Fourier transform infrared analysis (TG-FTIR) and pyrolysis-gas chromatography–mass spectrometry (Py-GC–MS). It was found that the content of released CO2 for FRV/A was higher than that of pure FRV, and the content of the flammable gases for FRV/A, such as hydrocarbons, aldehydes, ethers and alcohols, was lower than that of FRV. In this way, the flame retardancy of FRV was effectively enhanced after blending with A.

The flame retardancy of alginate/flame retardant viscose fibers investigated by vertical burning test and cone calorimeter

In this research, the flame retardancy of neat alginate fiber, flame retardant viscose fiber (FRV) and alginate/FRV (50/50) blending fibers were investigated by vertical burning and cone calorimeter tests. The vertical burning test showed that the afterflame time of alginate fiber was 0s, but alginate presented serious smoldering behavior with the afterglow time of 605s and damaged length of 85mm, while the afterglow time of FRV was 0s. When the FRV was incorporated into alginate with the weight ratio of 50/50, the afterglow time and damaged length were significantly reduced to 85s and 35mm, indicating the smoldering of alginate can be effectively decreased. The morphology and chemical structure of the alginate residual demonstrated that it was seriously destroyed during smoldering process, which was ascribed to its relative low initial thermal degradation temperature. Based on the thermal properties analysis, alginate and FRV fibers shared the concurrence of rapid degradation in the same temperature region of 250–300°C, through which, the compact and stable char formed by FRV can prevent the heat transmission and suppress the smoldering of alginate. Further, the cone calorimeter results demonstrated that the time to ignition (TTI) significantly increased and peak heat release rate (PHRR) decreased for alginate/FRV (50/50) compared with FRV. With this research, a new method to overcome the smoldering of alginate was proposed by blending with FRV

Preparation and characterization of solution spinning of protein/cellulose fiber: A new flame-retardant grade

A new flame-retardant protein viscose fiber with safely wearing performance has been prepared through blending protein solution, flame retardant (hexaphenoxycyclotriphosphazene) and viscose spinning solution, in which wool protein was used and added to spinning solution on the basis of 16% flame retardant, and the properties of the fiber were investigated. The product has more compact structure inside the fiber and evenly scattered small pores on the surface. Flame-retardant protein viscose fiber can reach the flame-retardant standard both before and after 30 times wash test, and the mechanical strength of the fiber was also improved. The introduction of hexaphenoxycyclotriphosphazene lowered the primary decomposition temperature of viscose fiber, reduced its weight loss. The flame-retardancy of the fiber can be improved by the introduction of protein. In thermal processes, the major product of thermal decomposition was CO2, no hazardous and noxious gases were released. Due to the introduction of protein, moisture regain of the fiber is a little lower than that of viscose fiber, but higher than flame-retardant viscose fiber. Warmth retention property was also improved. Friction coefficient of the product is lower than that of flame-retardant viscose fiber. Bulking intensity was increased, which is better than that of viscose fiber.

Preparation and properties of flame-retardant viscose fiber modified with poly[bis(methoxyethoxy)phosphazene

Poly[bis(methoxyethoxy)phosphazene] (PMEP) was synthesized and applied to the preparation of flame-retardant viscose fiber using wet spinning method. The structure of PMEP was characterized by FTIR and NMR. The combustibility and thermal stability of the flame-retardant viscose fiber containing different percentage of PMEP (0-20 %) were evaluated by limit oxygen index (LOI), 45 ° slope burning method, differential scanning calorimeter (DSC), and thermal gravity analysis (TGA). The results showed that the LOI of the flame-retardant viscose fiber containing 10 % or more PMEP could reach at least 28 % after normal family laundering, and the combustibility of the flame-retardant viscose fiber could reach the Japan industry standard JIS L1091-D (3 times of ignition). The analysis of the fiber thermal degradation suggested that PMEP as a macromolecular flame retardant had a multifunction of heat absorption, catalytic dehydration, carbonization, condensation-phase and gas-phase flame retardancy. The mechanical properties of the flame-retardant viscose fiber decreased insignificantly compared with that of virgin viscose fiber.

Preparation and characterization of cyclotriphosphazenekeratin/viscose fibers

The aim of this study is to develop a flame-retardant viscose fiber using the phosphazene derivative of a natural polymer. Hexachlorocyclotriphosphazene (HCCTP) and keratin were used as the raw materials to synthesize cyclotriphosphazenekeratin (CCTPK). The Fourier transform infrared spectroscopic results indicate that CCTPK was successfully synthesized. The thermal analysis shows that the introduction of phosphazene into keratin lowered the primary decomposition temperature, increased the decomposition rate, and caused less weight loss. CCTPK blended viscose fibers were prepared by the wet spinning method, and the properties of the fiber were investigated. Limiting oxygen index of the flame-retardant fiber containing 10 % flame retardant was 28.6 %, which decreased to 27.5 % after 30 washing cycles. After burning, the scanning electron microscopy image showed an inflated carbonized coat on the fiber surface. The effect of CCTPK on the mechanical properties of the fibers was insignificant. CCTPK was compatible with keratin, and the flame retardancy of the viscose fiber was significantly improved.

Preparation and Characterization of Flame-Retardant Viscose Fiber Treated with TAECTP

In this paper, hexachlorocyclotriphosphazene (HCCTP) was used as a raw material to synthesize triaminoethyloxy cyclotriphosphazene (TAECTP). After-finishing method was applied to the preparation of flame-retardant viscose fibers. LOI results showed that TAECTP was intrinsically flame retardant. After burning, inflated carbonized coat was found on the fiber surface. Thermogravimetric analysis (TG) indicated that primary decomposition temperature of the fiber moved up about 30°C, as compared with untreated viscose fiber. Loss on mechanical properties of fibers was insignificant. The introduction of TAECTP was compatible and the flame retardancy of viscose fiber was greatly improved with limited negative impact.

Research on Thermal Protective Performance of Thermal Insulation and Flame-Retardant Protective Clothing

Thermal insulation and flame-retardant (TIFR) protective clothing, which has good thermal protective performance (TPP), could protect people from high-temperature or flame in casting industry, the petrochemical industry, fire industry and et al. That is, TIFR protective clothing must have certain function of slowing or restraining heat transmission, and insulating radiant heat and convection heat from high temperature heat source. The construction of TIFR protective clothing is being developed from single layer to multi-layer fabrics made by flame-retardant (FR) fibre. In this paper, based on TPP-206 tester, the TPP coefficient of single and multi-layer fabrics with flame-retardant were measured, and the TPP of TIFR protective clothing was analyzed. TPP coefficient of single fabrics included the FR viscose non-woven fabric do not meet the standard. That of all of multi-layer fabrics meet the standard requirement, and the FR viscose/wool blended fabric is not suitable for fire fighter. It is significant and the most observable effect to put the PTFE membrane between the outer layer and the insulating layer. It could improve the overall thermal protection performance.