Flame retardant polyesters. III. Fibers

Most of the commercial flame retardant (FR) polyester fibers are produced using copolymerization with phosphorous FRs. We investigated the fiber properties, dyeing properties, and flame retardancy according to the phosphorous FR type. The physical properties of both the fibers are similar and suitable for textile application. But the dye adsorption rate is much faster in the case of main chain type. This is resulted from higher chain mobility analyzed by glass transition temperature. The main chain type FR polyester fiber adsorbed the dyestuff at lower temperature and reached exhaustion more quickly. And the resistance to chemicals such as acidic and alkaline solutions at high temperature have similar tendency with dye absorption. The migration of dyestuffs and chemicals into the polymer chain has good correlation with chain mobility of the polymers. The main chain type polyester fiber shows better flame retardancy than pendant type polyester, which might be brought about from more rapid degradation into polyphosphoric acid. The main chain type polyester fiber shows better flame retardancy than pendant type polyester. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Aqua-mediated in situ synthesis of highly potent phosphorous functionalized flame retardant for cotton fabric

Flame retardancy in various materials is becoming an increasingly important performance feature. In the textile industries, fire-related problems have become an important concern over the decade. Herein, the polyvinyl alcohol (PVA) and graphene-supported material were functionalized with trimethyl phosphate (TMP) for the synthesis of flame retardant (FR) composite material [graphene polymer functionalized trimethyl phosphate (GPTMP)] in the aqueous medium, which improves the stability of cotton fabric against flame. Graphene and PVA fabricated with phosphorus functional groups make the fabric more comfortable against fire and help to avoid further spreading of fire. The composite-coated fabric sustains for a long time on continuous flame with maintaining its initial shape and size. The GPTMP-coated fabric shows flame retardancy for up to 540 s on constant flame exposure, whereas control samples such as PVA-, graphene oxide-, and TMP-coated fabrics resist for up to 15, 20, and 14 s, respectively. The limiting oxygen index (LOI) and vertical flammability test (VFT) for synthesized composites were performed to confirm and support the flame retardancy property of GPTMP. The GPTMP shows the 35% LOI value and forms the char length of 2.6 cm during VFT. This work provides a simple and eco-friendly method to obtain novel GPTMP, which has a high potential as a FR for different fabrics, including cotton.     

Flame resistant cotton fabrics prepared by radiation-initiated polymerization with vinyl phosphonate oligomer and N-methylolacrylamide

Radiation-initiated polymerization of vinyl phosphonate oligomer (molecular weight 500–1000) and N-methylolacrylamide from aqueous solutions was investigated with cotton printcloth, flanelette, and sateen fabrics and with cotton (50%)–polyester (50%) flannelette fabrics. Determinations were made of the effects of radiation dosage, mole ratio of vinyl phosphonate in the oligomer to N-methylolacrylamide in aqueous solution, concentration of reactants, wet pickup of solutions on fabrics, and irradiation of both dry and wet fabrics on efficiency of conversion of oligomer and monomer in solution to polymer add-on. The effects of vinyl phosphonate oligomer and N-methylolacrylamide radiation-initiated polymerization on some of the textile properties of cotton printcloth and on flame resistances of cotton and cotton–polyester fabrics were evaluated. The breaking strength of modified cotton printcloth was about the same as that of unmodified fabric; however, the tearing strength and flex abrasion resistance of modified fabric were reduced. The textile hand of the modified printcloth fabrics that had flame resistance indicated: interaction between cellulose and vinyl phosphonate oligomer–poly(N-methylolacrylamide) and uniform deposition in the fibrous cross section (transmission electron microscopy); surface areas of heavy deposits of oligomer–polymer (scanning electron microscopy); and phosphorus located throughout the fibrous cross section (energy dispersive x-ray analysis). Polymerization of vinyl phosphonate oligomer and N-methylolacrylamide was radiation initiated with cotton–polyester fabric; however, this modified fabric did not have flame-resistant properties.     

Polyimide-coated fabrics with multifunctional properties: Flame retardant,UV protective,and water proof

Multifunctional technical textiles are of great interest both by industry and academia and these products are considered as high value-added products that contribute to the economies of countries. In this study, polyamic acid (PAA) was synthesized through polycondensation of pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (ODA) in dimethyl acetamide (DMAc) at low temperature. Then, PAA was coated onto woven cotton and polyester fabric by padding technique. Finally, polyimide (PI)-coated multifunctional cotton and polyester fabrics were obtained by an easy coating technique and low-temperature imidization. Thus, low cost, easily accessible and widely used cotton and polyester fabrics were converted to high-performance textile products, which are flame retardant, UV protective, acid resistant, and waterproof. The chemical, thermal, morphological, optical, mechanical, wettability, chemical resistance, and flame retardancy properties of developed fabrics were investigated. Optical results showed that both PI-coated cotton and polyester fabrics are UV-A protective compared to noncoated fabrics. Moreover, PI-coated samples have high contact angles which are 111.43° and 113.40° for PI-coated cotton (PI-c-C) and PI-coated polyester (PI-c-PET), respectively. Young's modulus of PI-c-PET fabrics increased four times more than noncoated polyester fabric. PI coating changed the burning behavior of both cotton and polyester fabrics in a positive way. All the test results showed that these developed multifunctional textile products might find an application in different industrial areas such as automotive, aerospace, protective clothing, and so on due to easy and inexpensive production techniques and also superior properties. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47616.     

Synthesize and Characterization of Flame Retardant Copolyesters PET/Phosphorus Compound

The aim of this study was to achieve a fiber‐grade poly(ethylene terephthalate) (PET) with flame retardancy properties. Flame retardant copolyesters based on ethylene glycol, terephthalic acid, and 3‐(hydroxyphenyl phosphinyl) propionic acid (HPP), as a flame retardant comonomer, were synthesized in presence of antimony trioxide catalyst at laboratory and semi‐industrial scales. At first, copolyesters with the lowest amount of flame retardant comonomer were synthesized at laboratory scale in a one‐pot reactor setup. In the second stage, flame retardant PET was synthesized in semi‐industrial pilot with HPP (PET‐HPP). The obtained copolyesters demonstrated almost identical intrinsic viscosities and other characteristics such as PET. Fourier transform infrared spectroscopy (FTIR), 1H‐NMR spectroscopy, and RMS test were performed. Flame retardancies were evaluated by a limiting oxygen index (LOI) test. The results indicated that the presence of FR significantly improved the flame retardancy and thermal stability of PET‐HPP. LOI values increased from 28% (PET) to 33 (PET‐HPP) (at laboratory scale) and 44% (at semi‐industrial scale). Differential scanning calorimetry analysis showed that the HPP polyester chain had a higher flexibility compared to PET, due to lower glass transition temperature. The effect of adding FR with regard to the thermal stability of PET‐HPP was investigated via thermogravimetric analysis. The physical properties of both the polymers are similar and suitable for textile application. J. VINYL ADDIT. TECHNOL., 25:262–270, 2019. © 2018 Society of Plastics Engineers     

Flame-resistant polyester/cotton fabrics

New experimental results are reported for the modification of 50/50 polyester/cotton blend fabrics made from bromine-free and bromine-containing polyester with a reactive flame retardant compound of high phosphorus content. Reaction of the cotton in the blend with methyl-phosphonic diamide yields modified fabrics in which flame resistance is attained without impairment of fabric hand. The level of flame resistance depends on the amount of insolubilized phosphorus in the treated fabric, but the hand is essentially unchanged even for fabrics of high phosphorus content which pass the vertical test of DOC-FF-3-71. The results of this work provide a basis for improved definitions of future approaches to the development of flame resistant polyester/cotton blend fabrics.     

The Effect of Selected Phosphates on the Flame Retardancy of Cotton and Polyester Fabrics

The comparative effects of three selected phosphates on the flame retardancy of pure cotton and polyester fabrics have been chosen from the author's previous investigations. Earlier described procedure for the evaluation of flame retardancy were used. The optimum loading required to achieve flame retardancy indicated the inferiority of sodium polymetaphosphate as compared with the others.     

Preparation and performance evaluation of phosphorus-nitrogen synergism flame-retardant water-borne coatings for cotton and polyester fabrics

Three phosphorus-nitrogen content effective synergist flame-retardant water-borne coatings have been synthesized, and their structures were characterized by infrared spectroscopy. Cotton and polyester fabrics have been treated by coatings to improve their flame retardancy. The thermal performances and flame retardant properties of treated samples were investigated by thermogravimetric analysis (TGA), horizontal flame test, vertical burning test, limiting oxygen index (LOI), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), respectively. The combustion performances of cotton and polyester fabrics have proven to be strongly affected by flame-retardant coatings and HFD-coating performed the best. As a result, the LOI value of treated cotton increased to 22.5, and the UL-94 value of treated polyester achieved V-0. In addition, the antistatic behavior, hydrostatic pressure, tearing strength and wrinkle recovery angle of samples were studied carefully, and the results showed that all of these performances were improved.     

Possible phosphorus‐bromine synergy in polyester‐cotton fabrics treated with tetrabromobisphenol‐A and diammonium phosphate

Polyester/cotton fabrics were treated with tetrabromobisphenol‐A (TBBA)/epichlorohydrin (EPI) aqueous solution, followed by being treated with diammonium phosphate (DAP)/urea solution. The optimum mole ratio of EPI to TBBA was determined. The synergism of TBBA and DAP was found to operate on the treated fabrics. The maximal synergism was obtained when the bath concentration of TBBA was equal to that of DAP. The mechanism of flame‐retardancy was analyzed by thermogravimetry and residue number. The flame‐retardancy of the polyester/cotton fabrics treated with TBBA/DAP was found operative mainly in the condensed‐phase mechanism. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 172–177, 2002; DOI 10.1002/app.10292     

Flame-retardant Finishing of Textiles

The need for flame-retardant finishing of textiles is examined in the context of the hazards of textile flammability, associated legislation and procedures for assessing textile burning behaviour. The functions of flame-retardant finishes and durable finishes developed specifically for cellulose, wool and man-made fibres are described in depth. Multipurpose finishes for both cellulose and wool textiles in which flame retardancy is only one property conferred on the textile are examined. Fibre blends present a particular problem and special attention is paid to discussing those finishes applied to polyester/cotton blended fabrics. The laundering behaviour and consequent finish durability are reviewed. In addition, the effects that applying flame-retardant finishes have on textile properties and performance are considered. Recent developments in methods used to apply flame-retardant finishes are outlined.     

新型含磷阻燃剂的制备及性能

以双三羟甲基丙烷为原料合成一种新型含磷阻燃剂,该阻燃剂分子量较大,具有稳定的环状结构,热稳定性高于常用阻燃剂,阻燃效果好。探讨了原料配比、反应温度、反应时间对产率的影响,考察了目标产物的热稳定性能及其对不同织物的阻燃效果,用傅里叶变换红外光谱仪表征了中间体及目标产物的结构。结果表明,当原料配比为1∶3时,磷化温度为50℃,磷化时间5h,胺化温度为75℃时,反应效果较好,收率可达90%以上。目标产物对于锦纶的阻燃效果比较明显,对涤纶、棉有一定的阻燃效果,对于混纺、腈纶阻燃效果不明显。     

Verification Concerning the Relative Superiority of a Cellulosic Fabric with Regard to Polyester in Terms of Flammability

In order to prove the superiority of cotton fabric to polyester with regard to flammability, we have studied the effect of Graham's salt as a moderate and nondurable finish on the flammability of pure polyester and cotton fabric. The laundered bone-dried, weighed fabrics were impregnated with suitable concentration of aqueous Graham's salt solutions by means of squeeze rolls and drying at 110°C for 30 min. They were then cooled in a desiccator, reweighed with analytic precision, and kept under ordinary conditions before the accomplishment of the vertical flame test. The optimum add-on value to impart flame retardancy was about 43.65% for polyester fabric and 36.78% for cotton fabric. The results obtained comply with the Coating Theory. Moreover, the superiority of cotton fabric to polyester fabric in terms of combustibility has been deduced.     

Effects of oily contamination and decontamination on the flame resistance of thermal protective textiles

This paper reports an experimental study wherein flame resistance and limiting oxygen index of protective fabrics were determined before and after contamination with oil and after decontamination. Experimental variables were presence of contamination, laundry treatment, number of contamination/decontamination cycles, and fabric type. Although laundering with pre‐wash products alone was the most effective in removing oil, some product residues may have contributed to the increased flammability of some fabrics. Thus, use of that product was truly effective only if combined with detergent. For two fabrics higher flammability was noted after five contamination/decontamination cycles than after one. Of the three fabrics studied, aramid specimens retained the least oil, and although they had the highest flammability both before and after contamination, it increased the least with contamination. The FR cotton/nylon fabric retained the most oil after decontamination, but had better flame resistance than aramid. Much of the oil remained in the interior of cotton fibres making it difficult to remove but also less accessible for vaporization and combustion. For the aramid/FR viscose, energy from combustion of residual oil activated the FR additive, thereby reducing apparent fabric flammability, but this FR transference effect occurred only up to an optimum quantity of oil. Copyright © 2010 John Wiley & Sons, Ltd.     

Flame‐retardant fabric systems based on electrospun polyamide/boric acid nanocomposite fibers

To examine the feasibility of developing flame‐retardant‐textile coated fabric systems with electrospun polyamide/boric acid nanocomposites, fiber webs coated on cotton substrates were developed to impart‐fire retardant properties. The morphology of the polyamide/boric acid nanocomposite fibers was examined with scanning electron microscopy. The flame‐retardant properties of coated fabric systems with different nanoparticle contents were assessed. The flame retardancy of the boric acid coated fabric systems was evaluated quantitatively with a flammability test apparatus fabricated on the basis of Consumer Product Safety Commission 16 Code of Federal Regulations part 1610 standard and also by thermogravimetric analysis. The 0.05 wt % boric acid nanocomposite fiber web coated on pure cotton fabric exhibited an increment in flame‐spreading time of greater than 80%, and this indicated excellent fire protection. Also, the coated fabric systems with 0.05% boric acid nanocomposite fiber webs exhibited a distinct shift in the peak value in the thermal degradation profile and a 75% increase in char formation in the thermooxidative degradation profile, as indicated by the results of thermogravimetric analysis. The results show the feasibility of successfully imparting flame‐retardant properties to cotton fabrics through the electrospinning of the polymer material with boric acid nanoparticles. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

硅氮系阻燃黏胶纤维的结构与性能研究

分析了硅氮系阻燃黏胶纤维的结构与性能,探讨其阻燃机制。通过扫描电子显微镜、X射线衍射、力学性能以及极限氧指数等测试,分析了硅氮系阻燃剂含量对纤维阻燃性能、热性能和力学性能等的影响。结果表明:当阻燃剂质量分数为20%时,纤维的干态断裂强度为2.1 cN/dtex,极限氧指数为28%,在满足纺织服用需求的同时,达到国家阻燃标准,兼具安全环保与良好的阻燃性能。     

Photocuring of acrylate oligomers containing pentabromo benzylacrylate as flame‐retarding monomer and properties of cured films

Photocuring of formulations containing polyurethane and unsaturated polyester acrylate oligomers and a flame‐retarding (FR) monomer, that is, pentabromo benzylacrylate, with various α‐cleavage–type photoinitiators were studied. The effects of each photoinitiator on photocuring efficiency in both the presence and the absence of the FR monomer were examined. The flame retardancy and both physical and mechanical properties of the cured films were also investigated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1181–1189, 2002     

Thermal analyses of flame-retardant twills containing cotton,polyester and wool

Medium weight twill fabrics constructed from cotton and cotton blended with polyester and/or wool were analyzed under nitrogen by three thermoanalytical techniques. Fabrics were tested both before and after treatment with [tetrakis(hydroxymethyl)phosphonium] sulfate (THPS), urea, and trimethylolmelamine. The presence of all fibers was distinguishable in differential scanning calorimetric analysis (DSC) of untreated fabrics; the relative positions of the endothermic, decomposition peak temperatures were only slightly changed. After flame-retardant (FR) treatment, the blended cotton and wool fibers were altered. Both fibers decomposed as exotherms during DSC analysis. These data supported earlier microscopical, X-ray evidence that wool fibers were actually reacting with the FR treatment. The two DSC peaks for polyester polymer melting and decomposing remained unaffected by either blending with other fibers or the presence of the FR finish on the fabric. There was excellent agreement between DSC peak temperatures and the temperature of maximum rate of weight loss obtained from thermogravimetric analysis (TGA). Blending cotton with either of these fibers increased the residue measured after TGA. The increased residue correlated with increased flame resistance as measured by the 45° angle, edge-ignition burning rate test.     

Flame retardant finishing of the polyester/cotton blend fabric using a cross‐linkable hydroxy‐functional organophosphorus oligomer

Blend fabrics of cotton and polyester are widely used in apparel, but high flammability becomes a major obstacle for applications of those fabrics in fire protective clothing. The objective of this research was to investigate the flame retardant finishing of a 50/50 polyester/cotton blend fabric. It was discovered previously that N,N′‐dimethyloldihydroxyethyleneurea (DMDHEU) was able to bond a hydroxy‐functional organophosphorus oligomer (HFPO) onto 50/50 nylon/cotton blend fabrics. In this research, the HFPO/DMDHEU system was applied to a 50/50 polyester/cotton twill fabric. The polyester/cotton fabric treated with 36% HFPO and 10% DMDHEU achieved char length of 165 mm after 20 laundering cycles. The laundering durability of the treated fabric was attributed to the formation of polymeric cross‐linked networks. The HFPO/DMDHEU system significantly reduced peak heat release rate (PHRR) of cotton on the treated polyester/cotton blend fabric, but its effects on polyester were marginal. HFPO/DMDHEU reduced PHRR of both nylon and cotton on the treated nylon/cotton fabric. It was also discovered that the nitrogen of DMDHEU was synergistic to enhance the flame retardant performance of HFPO on the polyester/cotton fabric.     

丽赛织物洗涤性能研究

测试了纯棉织物以及棉／丽赛、棉／涤纶和棉／粘交织物洗涤一定次数后拉伸性能和悬垂性能的变化，试验结果表明，经过10次洗涤后棉／丽赛交织物的耐洗涤性能较纯棉织物好，比棉／粘交织物有明显提高。     

Influence of moisture on the flame retardance of textile fabrics

For cotton fabric not treated with a flame retardant (FR), the oxygen index (OI) increases slowly but at a constant rate with moisture content (MC). Above a MC of roughly 33% which roughly equals the water fiber saturation point of the cotton fiber, the increase becomes more rapid but the relation appears to remain linear. The relation between OI and MC is also linear for all the FR cotton fabrics examined up to an OI of at least 40. It is suggested that the moisture in the FR samples is not reducing flammability by entering into solid and/or gaseous phase reactions but by absorbing thermal energy owing to the endothermic process of heating and vaporization. Empirical relations appear to be present between the inherent hydrophilicity of the FR cotton fabrics and the OI of the dry fabric (OI)_o and the temperature of the zenith of the first exothermic peak for the FR cotton fabrics as determined by differential thermal analysis. OI–MC relations for wool fabric and wool treated with an FR are similar to those found for the cotton fabrics except that the slopes of the lines found for the wool samples are lower than those of the equivalent cotton samples. The relation reported by Van Krevelen between OI and char residue for polymeric materials is tested for both the cotton and wool samples. Agreement with Van Krevelen's relation is not good when (OI)_o values are used. Better agreement can be obtained if OIs are determined on samples with MCs between 2 and 10%.