Correlation between limiting oxygen index and phosphorus/nitrogen content of cotton fabrics treated with a hydroxy‐functional organophosphorus flame‐retarding agent and dimethyloldihydroxyethyleneurea

The combination of a hydroxyl‐functional organophosphorus flame‐retarding agent (FR) and dimethyloldihydroxyethyleneurea (DMDHEU) was used as a durable flame‐retardant finish system for cotton fabrics. DMDHEU functions as a binder between FR and cotton cellulose, thus making this flame‐retarding system durable to home laundering. DMDHEU also provides nitrogen to this system, therefore enhances its performance. Limiting oxygen index (LOI) is one of the most commonly used parameters to indicate the flammability of textiles and other polymeric materials. In this research, we investigated the correlation between LOI and phosphorus/nitrogen content on the cotton fabric treated with that durable flame‐retardant system. Phosphorus concentration on the fabric was analyzed by inductively coupled plasma atomic emission spectroscopy, whereas the nitrogen content was determined indirectly by measuring the carbonyl band intensity in the infrared spectra of the treated fabric. We developed a statistical model to predict LOI of the cotton fabric treated with FR and DMDHEU based on the phosphorus concentration and the intensity of carbonyl band of DMDHEU on cotton. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1885–1890, 2003     

Combination of a hydroxy‐functional organophosphorus oligomer and a multifunctional carboxylic acid as a flame retardant finishing system for cotton: Part II. Formation of calcium salt during laundering

Multifunctional carboxylic acids, such as 1,2,3,4‐butanetetracarboxylic acid (BTCA), were used to bond a hydroxy‐functional organophosphorus oligomer (FR) to cotton fabric in the presence of a catalyst, such as sodium hypophosphite (NaH₂PO₂). Previously, it was found that the cotton fabric treated with FR and BTCA showed a high level of phosphorus retention after one home laundering cycle. However, the flame retardant properties quickly deteriorated as the number of home laundering cycles was increased. In this research, it was found that the free carboxylic acid groups bound to the cotton fabric form an insoluble calcium salt during home laundering, thus diminishing the flame retardant properties of the treated cotton fabric. It was also found that the free carboxylic acid groups on the treated cotton fabric were esterified by triethanolamine (TEA), and that the formation of calcium salt on the fabric was suppressed by the esterification of the free carboxylic acid groups by TEA. The cotton fabric treated with BTCA and the hydroxy‐functional organophosphorus oligomer significantly improved its flame retardance when a new catalyst system consisting of hypophosphorous acid (H₃PO₂) and TEA was used in the system. Copyright © 2003 John Wiley & Sons, Ltd.     

The combination of a hydroxy‐functional organophosphorus oligomer and melamine‐formaldehyde as a flame retarding finishing system for cotton

In previous research, it was found that melamine‐formaldehyde resin can be used as a binder for a hydroxy‐functional organophosphorus flame retarding agent (FR) on cotton. The role that trimethylol melamine (TMM) plays in this flame retarding system was studied. When TMM is applied to cotton, it forms crosslinks between cellulose molecules. When TMM is applied to cotton in the presence of FR, it reacts with FR to form a crosslinked polymeric network in addition to reacting with cotton. The formation of the crosslinked network improves the laundering durability of FR and also increases the fabric stiffness. The number of crosslinks among cotton cellulose formed by TMM decreases as the FR concentration in the system is increased. TMM also functions as a nitrogen provider to enhance the flame retarding performance of FR due to phosphorus–nitrogen synergism. Therefore, the amount of TMM used in a FR/TMM formula plays the most critical role in determining the effectiveness of this flame retarding system. The finish bath pH also plays a significant role in influencing the performance of the flame retarding system on cotton. The optimum pH was found to be around 4. Copyright © 2004 John Wiley & Sons, Ltd.     

Chitosan phosphate induced better thermal characteristics to cotton fabric

Chitosan phosphate was prepared and applied at different concentrations with and without low formaldehyde N‐methylol finishing agent (resin) to cotton fabrics. Chitosan phosphate was characterized by FTIR, nitrogen content, and phosphorus content. The so‐treated fabrics were monitored for thermogravimetric analysis (maximum decomposition temperature and residue contents after decomposition), nitrogen content, phosphorus content, tensile strength, and elongation at break. Results indicate that extent of reaction of chitosan phosphate with the cotton fabric relies on concentration of the former; increasing the concentration of the resin has practically no effect on this reaction though the resin functions as a chemical bridge between the chitosan phosphate and the cotton fabric. On the other hand, the nitrogen of the resin and the phosphorus of chitosan undergo synergetic effect and enhance the thermal properties of the treated cotton. Strength properties display higher values in the presence than in the absence of chitosan phosphate when the latter was used along with the resin. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2021–2026, 2007     

Flame‐retardant finishing in cotton fabrics using zinc oxide co‐catalyst

In this article, N‐Methylol dimethylphosphonopropionamide (FR) in combination with a melamine resin (CL), phosphoric acid (PA) catalyst and zinc oxide (ZnO) or nano‐ZnO co‐catalyst were used (FR‐CL‐PA‐ZnO or nano‐ZnO system) to impart flame‐retardant property on cotton fabrics. FR‐CL or FR‐CL‐PA‐treated cotton specimen showed roughened and wrinkled fabric surface morphology, which was caused by the attack of the FR with slightly acidity. In addition, FTIR analysis showed some new characteristic peaks, carbonyl, CH₂ rocking and CH₃ asymmetric and CH₂ symmetric stretching bands, in the chemical structure of treated cotton specimens. Apart from these, the flame ignited on the flame‐retardant‐treated fabrics (without subjected to any post‐wet treatment) extinguished right after the removal of ignition source. However, FR‐CL treated specimens were no longer flame‐resistant when the specimens subjected to neutralization and/or home laundering, while FR‐CL‐PA treated specimens showed opposite results. By using 0.2% and 0.4% of ZnO or nano‐ZnO as co‐catalyst, the flame spread rate of neutralized and/or laundered test specimens decreased, even the specimens were undergone 10 home laundering cycles. Moreover, flame‐retardant‐treated cotton specimens had low breaking load and tearing strength resulting from side effects of the crosslinking agent used, while addition of ZnO or nano‐ZnO co‐catalyst could compensates for the reduction. Furthermore, the free formaldehyde content was dropped when ZnO and nano‐ZnO co‐catalyst was added in the treatment. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of chicken‐feather protein‐based flame retardant on flame retarding performance of cotton fabric

A new kind of eco‐friendly chicken‐feather protein‐based phosphorus–nitrogen‐containing flame retardant was synthesized successfully with chicken‐feather protein, melamine, sodium pyrophosphate, and glyoxal. And its structure was characterized by Fourier transform infrared spectroscopy, and the thermogravimetry of the agent was analyzed. Then the flame retarding performances of the chicken‐feather protein‐based flame retardant and in combination with the borax and boric acid in application to a woven cotton fabric were investigated by the vertical flammability test and limited oxygen index test. In addition, the surface morphologies of the treated and untreated fabrics were conducted by the scanning electron micrographs (SEM), and the thermogravimetric analyses of the treated and untreated cotton were explored, and the surface morphologies of char areas of the treated and untreated fabrics after burnt were tested by the SEM. The results showed that the flame retardancy of the cotton fabric treated by the chicken‐feather protein‐based flame retardant in combination with borax and boric acid was improved further, and the combination of the chicken‐feather protein‐based flame retardant and borax and boric acid could facilitate to form a homogenous and compact intumescing char layer, and the combination of them plays a good synergistic effect in the improvement of the flame retardancy of the treated cotton fabric. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40584.     

Preparation and application of ultrahigh‐pressure‐homogenised aminosilicon‐based softeners

Five different aminosilicon‐based softeners were prepared by ultrahigh‐pressure homogenisation, and changes in their particle sizes and spectroscopic properties were investigated. Moreover, the yellowing characteristics and mechanical properties of cotton fabrics treated with the homogenised softeners were determined. Homogenisation significantly decreased the average particle sizes and particle size distribution without destroying the micelles. In particular, from the results on changes in the whiteness and yellowness of a cotton fabric treated with a silicon‐based softener, it was confirmed that homogenisation suppresses the yellowing of the fabrics.     

Comparative study of colour yield of cotton knitted fabric made by torque‐free ring‐spun yarns

Torque‐free ring spinning is a new spinning technology that has produced yarns with low twist and balanced torque. In this study, a commercially torque‐free ring‐spun yarn, namely Estex yarn, with three types of cotton fibre, i.e. Pima, upland and organic cotton, were used. Cotton fabric samples were knitted with Estex yarns and conventional ring‐spun yarns. The fabric samples were then dyed with two reactive dyes, Remazol Black B and Remazol Brilliant Blue R Spec., and the fabric dyeability was measured in terms of reflectance and colour yield. Finally, the results were analysed using the statistical software package SPSS and the results revealed that fabric samples manufactured by Estex yarns could achieve a better colour yield than conventional ring‐spun fabric samples. In addition, the Pima cotton gave the best colour yield, followed by upland cotton and organic cotton.     

Development of flame retardancy properties of new halogen‐free phosphorous doped SiO2 thin films on fabrics

In this study, flame retardancy properties of fabrics treated with phosphorous (P) doped and undoped SiO₂ thin films were developed by sol–gel technique. As to this aim, P‐doped and undoped SiO₂ film were coated on cotton fabric from the solutions prepared from P, Si‐based precursors, solvent, and chelating agent at low temperature in air using sol–gel technique. To determine solution characteristics, which affect thin film structure, turbidity, pH values, and rheological properties of the prepared solutions were measured using a turbidimeter, a pH meter, and a rheometer machines before coating process. The thermal, structural, and microstructural characterization of the coating were done using differential thermal analysis/thermograviometry, fourier transform infrared spectroscopy, X‐ray diffractometry, and scanning electron microscopy. In addition, tensile strength, wash fastness, flame retandancy, and lightness properties of the coated fabrics were determined. To compensate the slight loss of tensile strength of samples, which occurred at the treated fabrics with P‐doped Si‐based solutions, the cotton fabrics were coated with polyurethane films during second step. In conclusion, the flame retardant cotton fabric with durability of washing as halogen‐free without requiring after treatment with formaldehyde was fabricated using sol–gel processing for the first time. Moreover the cotton fabrics, which were treated with P‐doped Si‐based solutions and then coated with polyurethane at second step, still has got nonflammable property. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Flame retardant finishing of cotton fleece fabric: Part V. Phosphorus‐containing maleic acid oligomers

The high flammability of cotton fleece makes it necessary to apply a flame retardant system on cotton fleece so that it can meet the federal regulation ‘Standard for the Flammability of Clothing Textiles’ (16 CFR 1610). The objective of this research was to reduce the flammability of cotton fleece using the phosphorus‐containing maleic acid oligomers (PMAO) synthesized by aqueous free radical polymerization of maleic acid. We found that PMAO can be bound to cotton fleece by esterifying with cotton cellulose with sodium hypophosphite as the catalyst. Both the 45^° flammability and limiting oxygen index data indicated that the treatment of cotton using PMAO reduced the flammability of cotton fleece. The micro‐scale combustion calorimetric data revealed that PMAO reduced the peak heat release rate and heat release capacity of the treated cotton woven fabric. The cotton fleece treated with PMAO/NaH₂PO₂ passed the federal flammability test (16 CFR Part 1610) and achieved ‘Class 1’ flammability. The PMAO bound to cotton was durable to multiple home laundering cycles. The treated fleece also showed high strength retention with little change in fabric whiteness. The use of triethanolamine as an additive modestly enhanced the performance of PMAO with no significant changes in fabric physical properties. Copyright © 2009 John Wiley & Sons, Ltd.     

Improvement in the flame retardancy of cotton fabric by admicellar polymerization of 2‐acryloyloxyethyl diethyl phosphate using an anionic surfactant

The phosphorus‐containing acrylate monomer, 2‐acryloyloxyethyl diethyl phosphate (ADEP), was synthesized and applied to cotton fabric by using admicellar polymerization. Sodium dodecylbenzene sulfonate was used as the anionic surfactant. The film of polymerized monomer (PADEP) formed on the cotton surface was characterized by FTIR‐ATR spectroscopy and SEM. Thermal and flame retardant properties of PADEP‐coated cotton were investigated by TGA and flammability tests. Results showed that PADEP polymer film was successfully formed on the cotton fabric. The TGA and DTG analyses showed that the phosphorus‐containing PADEP lowered the decomposition temperature of the treated fabric resulting in a higher char yield than in the case of untreated cotton. The flammability tests showed that the treated cotton had much improved flame retardancy property after the treatment. The treated fabric also retained its good pliability and soft touch with good air permeability. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Investigation on phosphorus halogen‐free flame‐retardancy systems in short glass fiber‐reinforced PC/ABS composites under rapid thermal cycle molding process condition

In this study, standard test specimens with flame‐retarded short glass fiber‐reinforced PC/ABS materials were fabricated under rapid thermal cycle injection molding condition by selecting a potassium perfluorobutane sulfonate flame retardant specially used for PC, FR2025, and two kinds of aryl phosphorus halogen‐free flame retardants, UN707 and PX‐220. The flame‐retardancy effect of the above different flame retardants on the studied systems was compared through combustion tests of the specimens. Meanwhile, the thermal and mechanical properties of flame‐retarded composites were studied by using the thermogravimetry analysis, dynamic mechanical thermal analysis (DMTA), and universal testing machine. The results show that the “candlewick effect” of fibers exacerbates the fire behavior of composites. With the increase of the aryl phosphorus halogen‐free flame retardants, the flame‐retardancy effect of composites is obviously improved, and the maximum thermal degradation rate of composites is significantly decreased. The UL94 combustion rating is improved, and the time of residual flame is substantially reduced with the increase of PC content under the same content of flame retardant. The DMTA results show that the flame retardants have a reinforcement action on PC/ABS matrix. However, the macroscopic mechanical properties are slightly decreased in the glass fiber‐reinforced composites because of the destructive effect of the flame retardants on the interface compatibility between matrix and fibers; the scanning electron microscopic micrographs of tensile fracture fully prove this action mechanism of flame retardants. In addition, the addition of toughener and antidripping additive significantly affects the flame retardancy and mechanical properties of composites. POLYM. COMPOS., 36:1653–1663, 2015. © 2014 Society of Plastics Engineers     

Novel phosphorus‐based flame retardants containing 4‐tert‐butylcalix[4]arene: Preparation and application for the fire safety of epoxy resins

A novel flame retardant (FR) containing phosphorus and 4‐tert‐butylcalix[4]arene was synthesized and characterized. The FR combined with ammonium polyphosphate (APP) was then incorporated into epoxy resins (EPs) at different ratios. The flame retardancy, thermal stability, and smoke‐releasing properties were investigated. The limiting oxygen index was as high as 30.8% when the mass fraction ratio of the FR to APP was 1:2. The improved FR effect have been due to the combined FR effects between the FR and APP. The char residue content at 800 °C under a nitrogen atmosphere increased notably from 8.22% to 17.6% when the FR APP was incorporated into EP; this indicated an improvement in the thermooxidation resistance. From the cone test, we found that both the total heat‐release and peak heat‐release rate of the FR resins were reduced. Compared to the resins containing no FRs, the smoke‐production rate and total smoke‐production results indicate that the FR resins also exhibited good smoke‐suppression properties. Generally, the stable char layer of the FR APP–EP not only effectively prevented the release of combustion gases but also hindered the propagation of oxygen and heat into the interior substrate. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45105.     

Effect of Silicone Nano,Nano/Micro and Nano/Macro‐Emulsion Softeners on Color Yield and Physical Characteristics of Dyed Cotton Fabric

The study of silicone nano‐emulsions and softeners to alter physical properties of undyed cotton fabric has recently gained a substantial interest. However, systematic investigation of silicon nano‐emulsion softeners on dyed cotton fabric has not so far been conducted. This paper deals with the application of silicone nano‐, micro‐, and macro‐emulsion softeners, and combinations of nano/micro and nano/macro, on dyed cotton fabric. We report the effect of silicon nano/micro‐ and nano/macro‐emulsion softeners on color yield and physical characteristics of dyed cotton fabric. All bleached fabrics were dyed with CI Reactive Black 5 and then treated with known concentrations of silicone softeners by the pad‐dry method. The silicone nano‐emulsion was combined with micro‐ and macro‐emulsion softeners using blending ratios of nano/micro (1:1) and nano/macro (1:1). Treated fabrics were compared in terms of physical properties such as fabric handling, wrinkle recovery angle, bending length, abrasion resistance and tensile strength. The color changes were evaluated by color yield (K/S) values and total color difference (ΔE_cmc). The results revealed that the silicon nano‐emulsion had better physical properties than micro‐, macro‐ and combination nano/micro‐ and nano/macro‐emulsion softeners. Among all treated samples, nano‐emulsion softeners showed better ΔE_cmc values. Scanning electron microscopy analysis suggests that the fiber morphology of treated fabrics was very smooth and uniform.     

Dyeing properties of novel electrolyte‐free reactive dyes on cotton fibre

A series of electrolyte‐free reactive dyes containing two quaternary ammonium salt groups as soluble moieties and one epoxy structure as the reactive group have been synthesised. The structures of the synthesised dyes were confirmed by Fourier Transform–infrared, proton nuclear magnetic resonance and elemental analysis, and their dyeing properties on cotton were studied using an electrolyte‐free dyeing process. The results indicate that electrolyte‐free reactive dyes with these structures give a high exhaustion rate, a high fixation rate and good build‐up properties on cotton. Fastness properties were, in general, also very good. The optimal dyeing process of these electrolyte‐free dyes for cotton fibre was 60 °C with 20 g/l sodium carbonate.     

Thermal properties and combustion behavior of POSS‐ and bohemite‐finished cotton fabrics

A finishing process with polyhedral oligomeric silsesquioxane (POSS) and bohemite nanoparticles has been exploited for enhancing the thermal stability and flame retardancy of cotton fabrics. The thermal behavior of flame retardant treated cellulosic fabric has been studied by thermogravimetric analyses (TGAs). It has been found that such nanoparticles favor the carbonization of the cellulose and slow down the kinetics of thermo‐oxidation in air. At the same time, the finished fabrics have turned out to be more efficient with respect to neat cotton as far as the flame retardancy is concerned, pointing out an increase of the time to ignition (TTI) and a decrease of the heat release rate (HRR). Furthermore, a comparison between the fire performances of the nanoparticles under study and a commercial phosphorus‐based flame retardant has been investigated. The morphology and elemental composition present in the treated fabrics have been also investigated using scanning electron microscopy (SEM) coupled to the energy dispersive spectroscopy (EDS), and the results have been compared with the untreated fabric. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Flame‐retardant finishing of cotton fleece fabric: part I. The use of a hydroxy‐functional organophosphorus oligomer and dimethyloldihydroxylethyleneurea

Cotton fleece has become a popular fashion in recent years. However, most of the 100% cotton fleece fabric is not able to meet the federal flammability standard (‘16 CFR Part 1610: Standard for the Flammability of Clothing Textiles’) without chemical treatment. In this research, we investigated the use of the combination of a hydroxy‐functional organophosphorus oligomer (HFPO) as the flame‐retarding agent and dimethyloldihydroxylethyleneurea (DMDHEU) as the binder to reduce the flammability of cotton fleece. We found that HFPO is effective in reducing the flammability of the cotton fleece whereas DMDHEU enhances the effectiveness of HFPO due to phosphorus–nitrogen synergism. The flammability as well as other properties of the treated cotton fleece is affected by both the concentration of HFPO and that of DMDHEU. The cotton fleece treated with HFPO/DMDHEU passes the federal flammability standard and shows high strength retention with little change in fabric whiteness and hand. We also found that the flame‐retardant finishing system is durable to multiple home launderings. The combination of HFPO and DMDHEU has the potential to become a practical flame‐retardant finishing system to reduce the flammability of cotton fleeces. Copyright © 2006 John Wiley & Sons, Ltd.     

Microencapsulation and application of fluorine‐free water repellent agent‐AH102

Fluorine‐free water repellent agent, AH102, was microencapsulated by interfacial polymerization with polyurethane as shell material to restrict its hydrolysis and improve its dispersibility in water. The appearance of the resultant microcapsules was characterized with optical microscope and scanning electron microscope. Chemical structure of microcapsules was identified with Fourier‐transforming infrared spectrometer. The size and size distribution of the microcapsules were determined by laser particle size analyzer. The thermal property of the microcapsules was investigated by thermogravimetric analysis. The stability and dispersibility of the microcapsules in aqueous medium were characterized by evaluating the static water contact angles of the treated cotton fabrics with the emulsions of unencapsulated and microencapsulated AH102 at different storage intervals. The results showed that AH102 was successfully encapsulated and its stability and dispersibility in water were greatly improved. As expected, the emulsion of the microencapsulated AH102 became more stable than that of the unencapsulated one at water repellence to cotton fabric with increasing storage intervals. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of titanium dioxide on the flame‐retardant finishing of cotton fabric

In this study, titanium dioxide (TiO₂) or nano titanium dioxide (nano‐TiO₂) was used as a cocatalyst in the flame‐retardant (FR) formulation of N‐methylol dimethylphosphonopropionamide (Pyrovatex CP New, FR), melamine resin [Knittex CHN, crosslinking agent (CL)], and phosphoric acid (PA) for cotton fabrics to improve the treatment effectiveness and minimize the side effects of the treatment. For FR‐treated cotton fabrics, the flame extinguished right after removal of the ignition source with no flame spreading. However, after neutralization and/or home laundering, FR–CL‐treated specimens failed the flammability test, whereas the opposite results were obtained from FR–CL–PA‐treated specimens. A noticeable result was that the TiO₂/nano‐TiO₂ cocatalyst had a significant effect on decreasing the flame‐spread rate. Thermal analysis found that the FR‐treated specimens without wet posttreatment showed two endothermic peaks representing the phosphorylation of cellulose and acid‐catalyzed dehydration. In addition, the treated fabrics showed some new characteristic peaks in their chemical structures; these were interpreted as carbonyl bands, CH₂ rocking bands, and CH₃ asymmetric and CH₂ symmetric stretching. The surface morphology of the FR–CL–PA‐treated cotton specimens showed a roughened and wrinkled fabric surface with a high deposition of the finishing agent that had a lower breaking load and tearing strength, which resulted from the side effects of the CL used. However, the addition of a TiO₂ or nano‐TiO₂ cocatalyst could compensate for the reduction in the tensile strength. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

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.