Detection of copper(II) sulfate’s uniformity and its thermal behavior in flammability of cotton fabric

Blue vitriol (copper(II) sulfate pentahydrate), CuSO₄·5H₂O has been chosen and investigated for its effectiveness as a flame-retardant, when impregnated into cotton fabric (cotton with a plain structure; woven 180 g m⁻², with 22 numbers of yarns per 10 mm). Using the vertical flame test, the extent of resistance to burning of the specimens has been determined. The impregnation was accomplished via dipping and stirring of bone-dried, weighed fabrics into the individual and suitable concentrations of the salt at room temperature. Afterwards the samples were squeeze rolled and dried horizontally at 110°C for 30 min in an oven and cooled in a desiccator and reweighed with an analytical precision. They were then kept under ordinary conditions overnight prior the fulfillment of the vertical flame test. The efficient quantities of the aforesaid salt expressed in g per 100 g dry fabric have been determined in an average figure of 12.75%. Estimation of uniformity in a selected sample was carried out via a spectrophotometer and results are in favor of the heterogeneous distribution of the salt in the fabric’s middle sectors. However initial and final parts of specimen showed to be rather uniformed. Thermogravimetric analysis of the pure cotton and the treated ones with insufficient and effective amounts of the salt were fulfilled and their thermograms were compared and commented. The results obtained for the effect of copper(II) sulfate comply with ‘The Dust or Wall Effect Theory’. This action is also assigned to the condensed phase retardation.     

Synthesis of 9-substituted 1,8-dioxooctahydroxanthenes by using diethyl ethoxymethylenemalonate as a double Michael acceptor synthon

Tandem Michael addition/elimination/Michael addition/cyclization reactions of diethyl ethoxymethylenemalonate as a double Michael acceptor with cyclic ??-diketones furnished novel 9-substituted 1,8-dioxooctahydroxanthenes.     

Combustion pathway of cotton fabrics treated by ammonium sulfate as a flame-retardant studied by TG

The effect of ammonium sulfate (NH₄)₂SO₄ on the flammability of 100% cotton woven fabric (plain 144 g m⁻², the number of yarns 21 per 10 mm) has been of interest in this study. The laundered bone-dried, massed fabrics were impregnated with suitable concentration of aqueous ammonium sulfate solutions by means of squeeze rolls, drying and conditioning. Afterwards the specimen’s resistance to burning has been determined. The optimum add-on value of ammonium sulfate to impart flame-retardancy to cotton fabric was in a range about 10.55–13.62 g anhydrous salt per 100 g fabric. Thermogravimetry (TG/DTG) of the pure cotton and the treated one with the above-mentioned sulfate as well as for pure salt were also accomplished and their TG curves were compared and commented to detect the combustion’s pathway of the supported substrate. TG data confirm major mass loss in treated cotton. It occurred well below at a punctual duration of the thermal degradation zone of the polymer. So fewer flammable volatiles and more char could be produced during combustion. The results obtained are in compliance with gas dilution theory and also chemical action theory.     

Thermogravimetry studies of cotton fabric’s flame-retardancy by means of synergism of lithium bromide and antimony trioxide

The synergism of lithium bromide and antimony trioxide on the flame-retardancy of a cotton fabric (woven, plain 150 g m²) has been investigated in this study. The impregnations of cotton fabric with suitable individual additives and/or their appropriate admixed formulation were carried out. The flammability test has also been fulfilled using described procedure, in the earlier published articles. Their outcomes comply with thermogravimetry’s data. Moreover the latest mentioned outcomes support the catalytic effect of this synergism. Explanation of the data could be in favor of existing flame-retardation’s theories. Ultimately this synergism is in compliance with the green chemistry and economical viewpoints.     

Thermogravimetric analysis of a cotton fabric incorporated by ‘Graham’s salt’ applied as a flame-retardant

We have investigated the effect of ‘Graham’s salt’ as a phosphorous containing flame-retardant applied onto cotton fabric. The optimum loading of this salt to impart flameretardancy has been determined to be about 36.78-41-31 g salt per 100 g cotton woven fabric (plain 144 g m⁻²). Thermogravimetry of pure cotton, treated cotton fabric and the pure salt were accomplished. The curves were then compared and commented. They reveal that this salt thermosensibilized combustion of the treated substrate as a dehydrating agent. The results obtained fortified the ‘Chemical Theory’ and ‘Coating Theory’ evidenced the formation of carbonaceous residue upon the cellulosic substrate during the combustion.     

TG studies of synergism between red phosphorus (RP)–calcium chloride used in flame-retardancy for a cotton fabric favorable to green chemistry

The combined effect between calcium chloride and red phosphorus (RP) on the flame-retardancy of a cotton fabric (woven construction massing 152 g/m²) has been studied in this work. The laundered bone-dried massed samples were impregnated with suitable concentrations of individual aqueous red phosphorus suspensions and/or calcium chloride solutions and some bunches were impregnated with appropriate admixed solutions of the both chemicals. An acceptable synergistic effect was then experienced by using an admixed bath containing 0.20 F red phosphorus and 0.20 M calcium chloride for impartation of flame-retardancy to a cotton fabric. By using a vertical flame spread test the optimum mass of the mixture needed to donate flame-retardancy was obtained to be about 5.88 g anhydrous additives per 100 g dry fabric. Thermogravimetry (TG/DTG) results concerning untreated and treated cotton fabrics at the optimum addition were obtained and their curves were compared and commented, fortifying the flame spread tests outcomes. It can be deduced that the applied treatment functioned as a catalyst at the combustion’s temperature of the polymeric substrate and, thermosensibilized the combustion process. This synergism is in favor of green chemistry as well as the economical and industrial view points.     

TG comparison between the efficiency of deposited ammonium bromide and ammonium chloride on the flame-retardancy imparted to cotton fabric

This study investigates the effect of ammonium bromide and/or ammonium chloride as nondurable finishes on the flammability of 100% cotton fabric, (woven construction, weighing 144 g m⁻²). The laundered bone-dried, weighed fabrics were impregnated with suitable concentrations of aqueous ammonium bromide and/or ammonium chloride solutions by means of squeeze rolls and dried at 110°C for 30 min. Afterwards they were cooled in a desiccator, re-weighed with an analytical precision and kept under ordinary conditions before the fulfillment of the vertical flame test. The optimum add-on values to impart flame retardancy expressed in g anhydrous ammonium bromide and ammonium chloride per 100 g fabrics were individually obtained to be about 3.5–3.89 and 17.31–17.99%, respectively. Thermogravimetric analysis (TG/DTG) of pure cotton and the salts treated fabrics were fulfilled and their curves were compared and commented. The results obtained comply with free radical theory, and also proved the superiority of ammonium bromide for the impartation of flame-retardancy in regard to ammonium chloride.     

Thermogravimetry of deposited caustic soda used as a flame-retardant for cotton fabric

We have investigated the effect of caustic soda as a nondurable finish on the flammability of 100% cotton fabric (plain 180 g m^?2). On the contrary to the mercerization, during the impregnation process, no tension was applied. In order to attain the alkali cellulose onto the fabric, the subsequent neutralization was not followed. Each bunches of fabrics were dipped into individual aqueous solutions of sodium hydroxide, followed by means of squeeze rolls and drying at 110°C. After conditioning nightlong, by using our ‘vertical flame test’ the optimum add-on values to impart flame-retardancy into cotton fabric was determined as 1.3 g sodium hydroxide per 100 g fabric. Thermogravimetry and derivative thermogravimetry (TG/DTG) of pure cotton, treated cotton with sodium hydroxide at its optimum efficiency to impart flame-retardancy into the fabric was fulfilled and the obtained curves were compared and commented. The effectiveness of this hydroxide is attributed to the heat dissipation by the remaining material in the consumed ash. The results obtained are in favour of ‘dust or wall effect theory’ and also gas dilution theory.     

XRD characterization of the ashes from a burned cellulosic fabric impregnated with magnesium bromide hexahydrate as flame-retardant

The effect of magnesium bromide hexahydrate [MgBr₂·6H₂O] as a nondurable finish on the flammability of 100% cotton fabric, (woven construction, massing 150 g m⁻²) has been investigated. The laundered bone-dried, massed fabrics were impregnated with various concentrations of the aqueous above-mentioned salt solutions by means of squeeze rolls and drying in an oven at 110°C for 30 min. The specimens were then cooled in a desiccator, re-massed with an analytical balance and kept under standard conditions before the fulfillment of the vertical flame spread test. After several experiments the optimum add-on values to impart flame-retardancy expressed in g anhydrous magnesium bromide hexahydrate per 100 g fabric were determined to be about 5.6%. The ashes of the treated specimens were subjected to X-ray diffraction analysis (XRD), and the result was compared with data for pure MgO powder and/or MgBr₂ specimens. Consequently the existence of MgO was detected in the ashes.     

TG of a cotton fabric impregnated by sodium borate decahydrate (Na2B4O7·10H2O) as a flame-retardant

The effect of sodium borate decahydrate as a nondurable treatment on the flammability of 100% cotton fabric (woven plain 150 g m⁻²) has been investigated in this paper. The laundered bone-dried massed samples were impregnated with suitable concentrations of sodium borate decahydrate. Each bunches of fabrics were dipped into individual aqueous solutions of the salt, followed by means of squeeze rolls and drying at 110°C. By using a ‘vertical flame spread test’ the optimum add-on values to impart flame-retardancy onto cotton fabric was determined to be as 4.24 g salt per 100 g fabric. The objective of this study is thermogravimetry (TG) investigation of pure cotton, treated one with the salt at its optimum efficiency. So that outcomes could be compared and commented, finally the results obtained are in favor of ‘Chemical action theory’, ‘Condensed phase retardation’, ‘Dust or wall effect theory’ and also ‘Gas dilution theory’.