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 I. The chemical reactions

Multifunctional carboxylic acids, such as 1,2,3,4‐butanetetracarboxylic acid (BTCA), have been used as crosslinking agents for cotton cellulose to produce wrinkle‐resistant cotton fabrics and garments. Polycarboxylic acids were used to bond hydroxy‐functional organophosphorus oligomer to cotton, thus imparting durable flame retarding properties to the cotton fabric. This research investigated the chemical reactions between the hydroxy‐functional organophosphorus compound and BTCA on cotton. BTCA crosslinks cotton cellulose through the formation of a 5‐membered cyclic anhydride intermediate and esterification of the anhydride with cellulose. In the presence of the organophosphorus compound, BTCA reacts with both the organophosphorus compound and cellulose, thus functioning as a binder between cotton cellulose and the organophosphorus compound and making the flame retarding system durable to laundering. The cotton fabric treated by the combination of the organophosphorus compound and BTCA demonstrated lower wrinkle resistance and less tensile strength loss than that treated by BTCA alone. The phosphorus retention on the cotton fabric after one home laundering cycle was approximately 70%. Copyright © 2003 John Wiley & Sons, Ltd.     

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.     

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 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     

Properties of reaction products of hydroxymethylated 2-substituted 4,6-diamino-s-triazines with cotton

A study has been made of the reaction products of hydroxymethylated 2-substituted (X) 4,6-diamino-s-triazines (MXT) with cotton fabrics in the presence of zinc nitrate as catalyst. The reagents used were MXT having the following substituents: methoxy (MMT), isopropoxy (MIPT), methyl (acetoguanamine) (MAG), monoethylamino [N-(2-ethyl)melamine] (MEM), monohydroxyethylamino [N-(2-hydroxyethyl)melamine] (MHEM), and dihydroxyethylamino [N,N-bis(2-hydroxyethyl)melamine] (MBHEM) groups. Trimethylolmelamine (TMM), dimethylolurea (DMU), dimethylolethyleneurea (DMEU), and dimethylolethyltriazone (DMET) were also used for comparison. The molar ratio of total formaldehyde to 2-substituted 4,6-diamino-s-triazine (XT) residue in treated fabrics is larger in high-temperature curing than in low-temperature curing. In case of curing at 150°C for 5 min, MHEM and MBHEM crosslinked primarily with cellulose in a monomeric state, and the others in a oligomeric state. From these facts, the crosslinked structures were presumed. Infrared absorption spectra of the fabrics treated with MXT are discussed and a few physical properties of the fabrics are compared with those of the fabrics finished with TMM, DMU, DMEU, and DMET.     

A novel halogen‐free and formaldehyde‐free flame retardant for cotton fabrics

A novel halogen‐free and formaldehyde‐free flame retardant (FR), which contains phosphorus, nitrogen, and silicon, was synthesized for cotton fabrics considering the synergistic effect of phosphorus, nitrogen, and silicon. The structure of the new FR was characterized by Fourier‐trans‐form infrared spectroscopy, and the surface morphology of the treated fibre was observed using scanning electron microscope. The thermal property of the FR treated cotton fabric was studied through thermal gravimetric analysis. The TG results indicate that the FR can protect cotton fabric from fire to a certain degree. The vertical flammability test and limiting oxygen index results further indicate that the FR has excellent FR properties. Finally, the durability and other performance properties of the treated fabric were studied and the results show that the new materials can be used as a semi‐durable FR for cellulosic fibres. Copyright © 2011 John Wiley & Sons, Ltd.     

A study on distension index and distribution of crosslinks in formaldehyde-crosslinked cotton

A study on distension index (DI) and distribution of crosslinks is reported for cotton cellulose treated with selected swelling reagents and crosslinked by different processes with formaldehyde. Details of estimation of the distension index are also described. Distribution of crosslinks under different conditions of crosslinking has also been shown by electron microscopy. Marked differences in DI values and distribution of crosslinks in cellulose samples crosslinked under different conditions of treatments are discussed. The results of these analysis provide quantitative information on the gross uniformity of distribution of crosslinkages in the fiber structure of cotton celluloses.     

Char Formation in Flame‐Retarded Fibre–Intumescent Combinations. Part V. Exploring Different Fibre/Intumescent Combinations

Previous research work in our laboratory has indicated that the efficiency of certain flame‐retardant fibres can be further enhanced if certain interactive intumescents are dispersed on their surfaces. In our previously reported work we have successfully observed interactions between certain commercially available flame‐retardant cellulosic and regenerated cellulose (viscose) fibres and two melamine and phosphoric acid‐based intumescent systems. In the present work we have explored the use of other intumescent systems—melamine cyanurate, melamine borate, melamine oxalate, melamine pyrophosphate and an inorganic silicate‐based intumescent, Cylatherm. Two non‐cellulosic fibres—the novoloid (Kynol) and melamine‐formaldehyde (Basofil) were also explored in combination with different intumescent systems. These systems were studied by thermal analytical techniques to observe any possible interaction between FR fibre and intumescent components. Of these intumescents, only melamine borate and melamine pyrophosphate showed interactions with flame retardant cellulosic fibres and both Kynol and Basofil indicated char interactive tendencies with some of the phosphorus‐containing intumescents. Copyright © 2002 John Wiley & Sons, Ltd.     

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.     

无卤协效膨胀阻燃聚甲醛体系的性能和阻燃机理

针对聚甲醛(POM)难以阻燃的难题,采用酚醛树脂协效无卤膨胀阻燃剂复合阻燃POM,研究了酚醛树脂含量对POM阻燃性能和力学性能的影响以及相关的成炭阻燃机理.结果表明,酚醛树脂的含量对无卤膨胀阻燃POM体系的阻燃性能有重要影响,当体系中酚醛树脂的质量分数为0.5%～2.0%时,相应阻燃POM体系可达UL941.6 mm ...     

铝/磷/氮三元体系阻燃PU硬泡的制备与性能研究

以氢氧化铝、三聚氰胺和聚磷酸铵为阻燃剂制备了阻燃聚氨酯硬质泡沫,研究了添加氢氧化铝前后阻燃剂用量对聚氨酯(PU)硬泡的阻燃性能和力学性能的影响。结果表明,铝/磷/氮复配阻燃体系的阻燃效果优于磷/氮阻燃体系,阻燃剂总添加量达30份时,PU硬泡同时具备较好的阻燃性能和力学性能,氧指数为32,烟密度为74,平均燃烧时间为31 s,其压缩强度和拉伸强度分别为6.52 MPa和6.16 MPa。     

pH‐reversible magnetic gel with a biodegradable polymer

Polymer gels that react to external stimuli, such as pH, temperature, and electromagnetic fields, are an important class of materials. Such materials have pharmaceutical, industrial, and biomedical applications. Our intention in this study was to synthesize a stimuli‐responsive polymer gel with a biodegradable polymer. However, the chemical crosslinker, divinyl sulfone, which is most widely used for the crosslinking of this type of material, is highly toxic in nature. To overcome this problem, a reversible magnetic gel was synthesized with hydroxy propyl cellulose (HPC) and maghemite at pH 13 without with a chemical crosslinker. With a decrease in pH from 13 to 9, the gel formed a homogeneous dispersion of HPC particles with maghemite in it. This process was a reversible physical gelation where the crosslinks of the network had a physical origin (in this case, hydrogen bonding) and, therefore, were sensitive to variations in pH. When this physically prepared gel was compared with the chemically crosslinked one, no significant differences in structural properties were noted. At higher pH values, the gel was formed due to weak intermolecular hydrogen bonding, as observed by the broadening of the IR band in both the magnetic and nonmagnetic gels. Transmission electron micrographs also showed no significant difference in the gel morphology. Differential scanning calorimetry showed an increase in melting temperature for the gel sample compared to that of pure HPC. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3337–3341, 2004     

Catalytically synergistic effects of novel LaMnO3 composite metal oxide in intumescent flame‐retardant polypropylene system

The newly prepared LaMnO₃ was introduced as a novel perovskite composite metal oxide catalyst for the first time to improve the flame retardancy of flame‐retarded (FR) polypropylene with intumescent flame‐retardant (IFR) system consisting of ammonium polyphosphate (APP), pentaerythritol (PER), and melamine (MA). The synergistic effects of LaMnO₃ catalyst on the performance of IFR PP composites as well as the corresponding catalytically synergistic FR mechanism were investigated. The experimental results show that the incorporated LaMnO₃ catalyst plays an excellently catalytic and synergistic part in improvement of the flame retardancy of FR PP system. Compared with FR system without LaMnO₃, the incorporation of only 0.5 wt% LaMnO₃ into PP FR system could obviously improve the UL‐94 level from failure to V‐0 rating and decrease the micro‐scale calorimetry parameters peak heat release rate and heat release capacity. The remarkable improvement in flammability can be ascribed to the catalytic carbonization effect of LaMnO₃ on the intumescent flame retardant PP system. The incorporation of appropriate amount of LaMnO₃, on one hand, could improve the thermal stability of FR PP material, and on the other hand, could also act as nuclei to induce formation of the continuous, compact and smooth condensed phase intumescent charred layer with radialized spherulite‐like structure. As a result, the char yield and also the quality of the formed condensed phase charred layers are correspondingly enhanced remarkably, which is beneficial to improvement of the FR properties. POLYM. COMPOS., 35:2390–2400, 2014. © 2014 Society of Plastics Engineers     

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.     

Rheological and fire properties of a composite of unsaturated polyester resin and halogen‐free flame retardants

The main subject of the present research is to determine the impact of flame retarding fillers on macroscopic properties of composites. The effect on rheological properties of composition unsaturated polyester resin (UP) and flame retardant blend (FR) consisting of expandable graphite (EG) and or not modified silica and: (1) melamine polyphosphate (MPP) with ammonium polyphosphate (APP), (2) MPP with aluminum trihydrate (ATH), (3) only MPP was examined. Next, their influence on thixotropic properties of UP was estimated. FR fillers were compared according to their grain size, specific surface, and shape factor. Rheological properties were determined by applying hysteresis loop surface and thixotropy factor measuring. For the UP + FR composition, the dependence of grain morphological parameters, such as shape factor and specific surface, on viscosity and hysteresis loop surface was determined experimentally. All of the tested composites consisting of UP + 40% FR blend exhibits high flame resistance. An addition of only 2% of modified silica to all of the FR blends caused significant enlargement of hysteresis loop surface and thixotropy index. Hence, for the next stage of the research (an industrial test of GRP pipes casted by the centrifugal method) FR blend without modified silica was chosen. A composite consisting of UP, MP, APP and EG is characterized by lower heat release rate (HRR_max) (ca. 83%) and lower TSR (ca. 80%), ALMR (55%), and MARHE (73%) in comparison to UP resin; and that UP + FR composition exhibit satisfactory rheological properties as well. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44371.     

Thermal stabilities and flame retardancies of phloroglucinol‐based organo phosphates when applied to polycarbonate

A series of organo phosphorus flame retardants (FRs) based on aromatic phosphate and cyclic phosphate were synthesized in an attempt to develop an efficient FR for polycarbonate. Their successful synthesis was confirmed by FT‐IR and ¹ H and ³¹P NMR. Their thermal stability and flame retarding efficiency as a single‐component additive were investigated and compared with the commercial FR, resorcinol bis(diphenyl phosphate). The thermogravimetric analysis results revealed that the aromatic phosphate synthesized in this study, phloroglucinol diphenyl phosphate (PDP), shows a higher thermal degradation temperature and better flame retardancy even though it has a lower P content than cyclic phosphate‐based FRs. The flame retarding efficiency was evaluated by the UL‐94 test method. The V‐0 rating was achieved at a PDP loading of 2 wt% in polycarbonate in the presence of an anti‐dripping agent (1 wt%), which is better than that of resorcinol bis(diphenyl phosphate) and cyclic phosphate‐based FRs. The high thermal stability and P–OH generation tendency is responsible for the better flame‐retarding performance of PDP. The degradation path of PDP is also discussed. Copyright © 2012 John Wiley & Sons, Ltd.     

Flame-retardant viscose–polyester fabrics

For many purposes the natural-synthetic fiber-blend fabrics are more suitable than pure natural or synthetic products. It is often possible to obtain a maximum in clothing and textile technical properties by compensating the defects of one fiber by using an other totally different fiber. Many problems, however, have arisen in the production of flame-retardent fabrics because the use of synthetic fibers often makes the fire retardancy less effective. In our 2-year research project different fire-retardant (FR) viscose–polyesters fabrics were prapared at first in the laboratory scale. The natural type raw materials were Modal Prima viscose and normal FR–viscose cotton type staple fibers. The synthetic raw materials were FR–polyesters of the same type with two different flame retardants. Test fabrics were knitted in the laboratory by using seven blended yarns in the ratios 100/0, 80/20, 65/35, and 50/50 and vice versa. Cotton type PVC–fiber was also used in some experiments. All these test fabrics were also finished chemically by using normal crease-resistant (DMU, DMEU, DMDHEU, and TMM) and flameretardant (N,-methylolphosphonopropionamide and THPC) finishing chemicals. The textile and fire-retardant properties of the original and finished fabrics were estimated by using addon, tensile strength, LOI-value, and vertical flame test determinations. The mechanism of flame retardancy was also studied with DSC technique, P- and N-analysis and char investigations. The test results of viscose/polyester studies were compared with the results of cotton/polyester studies. After laboratory studies the best methods for FR–viscose/polyester fabric production were chosen, and the fabrics were manufactured. The fabrics were home-washed 20–50 times, and the textile and FR-properties were determined after each 10 washings. These results were again compared with results of cotton/polyester fabrics.     

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     

Preparation of polyamide resin‐encapsulated melamine cyanurate/melamine phosphate composite flame retardants and the fire‐resistance to glass fiber‐reinforced polyamide 6

In this study, melamine cyanurate (MCA)/melamine phosphate (MP) composite flame retardants were synthesized in the solution of phosphoric acid/polyamide 6 (PA6). Phosphoric acid acted as the solvent of PA6, catalyst of melamine‐cyanurate self‐assembly reaction and reactant of melamine‐phosphoric acid reaction. With the consumption of the acid, the pH value of the system increased, and the solved PA6 precipitated on the surface of the flame retardant particles to form polymeric encapsulation. This technology realized the synthesis and surface modification of the flame retardants in one process. The catalyst and solvent, phosphoric acid, was finally converted into the product MP, and need no an additional removing process. The encapsulated MCA/MP (EMCMP) composite flame retardants were successfully applied in the fire‐resistance to glass fiber (GF)‐reinforced PA6. Because the encapsulated layer of EMCMP was also PA6, good interfacial compatibility and effective dispersion of EMCMP in PA6 resin can be obtained, and the corresponding flame retardant materials showed excellent flame retardancy and mechanical performance. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1773–1779, 2006