Synthesis of PEG/TDI/F6 Adducts and Utilization as Water/Oil Repellents and Oily Stain Release Finishes for Cotton Fabric

Abstract

Four polyethylene glycol (PEG)/2,4-toluene diisocyante (TDI)/ perfluorinated aliphatic alcohols mixture (F6) adducts were prepared by reacting equimolar ratios of PEG (300, 600, 1000, or 2000), TDI, and F6 at 90°C for 90 min. All adducts, except that based on PEG 300 were water dispersible. These dispersions were used as water/oil repellent and oily stain release finishes for cotton fabric, via incorporation in a finishing bath containing DMDHEU. Factors affecting finishing process, using an adduct based on PEG 1000, such as DMDHEU concentration (0–60 g/l), adduct concentration (10–40 g/l), curing time (1–5 min), and temperature (140–170°C) were studied. Optimal performance properties of treated fabric, namely wrinkle recovery angle (WRA), %N, water/oil and stain release ratings, tensile strength, and breaking extension, were obtained using a padding bath containing DMDHEU (50 g/l), the adduct (30 g/l), and MgCl₂ · 6H₂O₂ (5 g/l), drying at 100°C/5 min and curing at 160°C/3 min. The inclusion of hydrophilic PEG segments in the adduct structure weakens the hydrophobic effect of perfluorinted segments, where the water repellency rating does not exceed a ceiling of 50, under the conditions employed. However, the adduct has a dual activity, where it repels oily stain in air and releases them during washing. A comparison among performance properties of fabric treated with adducts based on PEG 600, 1000, and 2000, showed that the fabric properties are practically the same, with little drops in WRA, %N, and oil repellency rating upon increasing PEG molecular weight from 600 to 2000.     

Synthesis of some new 2‐[(2,3‐dihydroinden‐1‐ylidene) hydrazinyl]‐4‐methylthiazole derivatives for simultaneous dyeing and finishing for UV protective cotton fabrics

Several 2‐[1‐(1,2‐dihydroinden‐3‐ylidene) hydrazono]‐5‐aryldiazo‐4‐methyl‐1,3‐thiazoles were synthesized by reaction of 1‐(1,2‐Dihydroinden‐3‐ylidene) thiosemicarbazide with different hydrazonyl chlorides. The products are water insoluble and UV absorbers, expressed UPF‐rating values, and their H₂O/DMF solutions were used in simultaneous dyeing and resin finishing of cotton fabrics. Results obtained show that finishing of cotton samples in presence of any of that dyes, irrespective of dye concentration, brings about an improvement in percent nitrogen, wrinkle recovery angle (WRA), dyeability, and UV protection rating values along with slight decrease of tensile strength (TS) compared with the untreated samples. Irrespective of dye structure, increasing the dye concentration from 0.5 and up to 1.7% results in an improvement in the percent nitrogen, TS and a remarkable improvement in both the dyeability, UPF‐rating values along with slight decrease in WRA and lower fastness properties of the treated fabrics. The treated fabrics was characterized using energy dispersive X‐ray analysis indicating the entrapped dye within the fabric structure. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Mechanical strength of durable press finished cotton fabric part V: Poly(vinyl alcohol) as an additive to improve fabric abrasion resistance

Multifunctional carboxylic acids, such as 1,2,3,4‐butanetetracarboxylic acid (BTCA), are effective crosslinking agents for cotton cellulose and have become the most promising nonformaldehyde durable press (DP) finishing agents to replace the traditional formaldehyde‐based dimethyloldihydroxylethyleneurea (DMDHEU) and its derivatives. DP finishing imparts wrinkle resistance to cotton fabrics and also severely reduces the strength and abrasion resistance of finished fabrics. In this research, we investigated the use of poly(vinyl alcohol) (PVA) as an additive to improve the abrasion resistance of the cotton fabric crosslinked by BTCA. We found that addition of PVA improves the abrasion resistance of the crosslinked cotton fabric when the concentration of PVA exceeds 0.6% in the finish solution. We also found that the use of PVA as an additive has no negative effect on the wrinkle recovery angle (WRA), DP rating, and tensile strength of the treated cotton fabric. This is probably because the molecules of PVA stay on the surfaces of the cotton fibers due to their large molecular sizes. PVA competes with cellulose to esterify BTCA, thus reducing the number of crosslinkages formed on the cotton fiber surface. The reaction of PVA and BTCA may also form a protective layer on the fiber surface, thus reinforcing the mechanically weak points on the fiber surface. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3940–3946, 2004     

Pore and crosslinking structures of cotton cellulose crosslinked with DMDHEU‐maleic acid

Two dicarboxylic acids (maleic acid and tartaric acid) were used in conjunction with DMDHEU as the crosslinking agents to treat cotton fabric samples. The treated fabrics then were dyed with direct red 81. The results show that the values of the dye absorption, equilibrium absorption, rate constants, and the pore index of structural diffusion resistance constant for the various crosslinking agents are ranked as DMDHEU‐tartaric acid > DMDHEU‐maleic acid > DMDHEU alone at the same dyeing temperature. The activation energies for the three crosslinked fabrics are in the rank of DMDHEU > DMDHEU‐maleic acid > DMDHEU‐tartaric acid. The CL length values for the various crosslinking agent systems are in the series of DMDHEU‐tartaric acid > DMDHEU‐maleic acid > DMDHEU alone for a given number of CL/AGU. The values of the pore index of structural diffusion resistance constant and dyeing rate constant are increased with the increase of CL length. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 143–148, 2005     

Antiwrinkle treatment of cotton fabric with a mixed sol of TEOS‐TTB/DMDHEU

This research explored the effect of a mixed sol on the physical properties of a treated fabric, and confirmed the crosslinkage of SiO₂ and dimethyloldihydroxyethyleneurea (DMDHEU) using Fourier transform infrared(FTIR) spectroscopy and nuclear magnetic resonance (NMR). In the experiment, DMDHEU was applied to a cotton fabric and different mole ratios of tetraethoxysilane (TEOS)/titanium (IV) n‐butoxide (TTB) were added. The mixture was then subjected to immersion, padding, drying, and curing. The results showed that hydrogen bonds had formed between SiO₂ and DMDHEU. The treated fabric had improved antiwrinkle properties, tensile‐strength retention, and yellowing degree when the mole ratio of TEOS was increased. By contrast, the softness of the fabric showed the opposite trend. When the mole ratio of TEOS/TTB was set at 10/1, the treated fabric showed a significant reduction of its antiwrinkle properties under both dry and wet conditions. The fabric treated with TEOS/TTB was superior to the traditionally treated fabric in terms of its ultraviolet (UV) light resistance. When the mole ratio of TEOS/TTB was 2.5/1 or 5.0/1, the addition of 10% DMDHEU during the treatment of the cotton fabric, followed by drying for 5 min at 80°C and curing at 150°C for 2 min, resulted in the fabric having improved and more balanced physical properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

New Approach for Easy-Care Finishing of Woolen Fabric

Abstract

A new approach for improving the durable press properties of wool fabric was investigated. The new technique involves padding with finishing bath containing DMDHEU at pH 2 using different acids, batching for 2 h at room temperature, followed by passing through a neutralizing bath containing triethanolamine (3 g/L) as an acid scavenger, and drying at 120°C/5 min. The results indicate that: i) wool fabric samples finished with the aforementioned technique acquire better durable press properties, higher whiteness index, and higher extent of post-dyeing, regardless of the acid used; ii) of the various acids used, HCl along with its amine salt, constitute a highly efficient catalytic system; iii) increasing DMDHEU concentration up to a certain limit has a positive impact on the dry and wet fabric resiliency, whiteness index, protection properties against moth attack, as well as on the extent of post-dyeing; and iv) the extent of improvement in the aforementioned properties is governed by the type of finishing agent and follows the descending order: Arkofix®NG > Fixapret®Eco, irrespective of the catalytic system used.     

Durable flame‐retardant finished cotton fabrics characterized by thermal degradation behaviors

After a series of investigations on the durable flame‐retardant finishes, it was thought to be important to study these durable flame‐retardant finished materials from the thermal analytical standpoint. Accordingly, cotton fabric was finished with N‐methylol dialkyl phosphonopropionamide (Pyrovatex C) by thermofixation and tetrakis (hydroxymethyl) phosphonium sulfate (THPS) precondensate by ammonia cure (Proban), as well as with THPS monomer by heat cure under various conditions, and subjected to the thermogravimetry (TG) to observe thermal degradation behaviors and obtain apparent activation energy (E_a). TG curves of Proban‐finished samples showed the largest shift to lower temperatures with a steep slope; thermofixed THPS‐finished sample gave a smaller shift with similar steep slope, whereas Pyrovatex‐finished samples exhibited a similar shift but with a gradual slope. E_a versus residual ratio curves led us to conclude that C N bond‐rich Proban polymer requires the highest E_a and decomposes with considerable rapidity, whereas ethylene‐bond‐rich Pyrovatex‐finished samples with melamine crosslinking decompose gradually with the lowest E_a. As for the relationship between flame retardance and E_a distribution in the process of thermal degradation, typical differences among the above three kinds of finished samples were found, which are compared and discussed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 975–987, 1999     

Durable antimicrobial treatment of cotton fabrics using N‐(2‐hydroxy)propyl‐3‐trimethylammonium chitosan chloride and polycarboxylic acids

N‐(2‐hydroxy)propyl‐3‐trimethylammonium chitosan chloride (HTCC), a water‐soluble chitosan quaternary ammonium derivative, was used as an antimicrobial agent for cotton fabrics. HTCC has a lower minimum inhibition concentration (MIC) against Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli compared to that of chitosan; however, the imparted antimicrobial activity is lost on laundering. Thus crosslinking agents were utilized to obtain a durable antimicrobial treatment by immobilizing HTCC. Several crosslinkers such as dimethyloldihydroxyethylene urea (DMDHEU), butanetetracarboxylic acid (BTCA), and citric acid (CA) were used with HTCC to improve the laundering durability of HTCC treatment by covalent bond formation between the crosslinker, HTCC and cellulose. The polycarboxylic acid treatment was superior to the DMDHEU treatment in terms of prolonged antimicrobial activity of the treated cotton after successive laundering. Also, the cotton treated with HTCC and BTCA showed improved durable press properties without excessive deterioration in mechanical strength or whiteness when compared to the citric acid treatment. With the addition of only 0.1% HTCC to BTCA solutions, the treated fabrics showed durable antimicrobial activity up to 20 laundering cycles. The wrinkle recovery angle and strength retention of the treated fabrics were not adversely affected with the addition of HTCC. Therefore, BTCA can be used with HTCC in one bath to impart durability of antimicrobial activity along with durable press properties to cotton fabric. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1567–1572, 2003     

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.     

Crosslinking of cotton cellulose in presence of alkyl di‐allyl ammonium salts. III. Study on pore structure of treated fabrics from dyeing kinetics

Two kinds of alkyl di‐allyl ammonium salts (alkyl groups = methyl and propyl) as crosslinking agents are combined with dimethyloldihydroxyethyleneurea (DMDHEU) to study rate constants, structural diffusion resistance constants, and other parameters of dyeing. The dye absorptions for the various crosslinking agents are ranked DMDHEU–propyl di‐allyl ammonium salt > DMDHEU–methyl di‐allyl ammonium salt > DMDHEU, and the equilibrium absorption values are ranked DMDHEU–propyl di‐allyl ammonium salt > DMDHEU–methyl di‐allyl ammonium salt > DMDHEU. The dyeing rate constants and structural diffusion resistance constants of the finished fabrics are in the order DMDHEU–methyl di‐allyl ammonium salt > DMDHEU–propyl di‐allyl ammonium salt > DMDHEU; however, the activation energies are ranked inversely. The treated fabrics for DMDHEU–alkyl di‐allyl ammonium salts have a larger pore structure than those for DMDHEU. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 862–866, 2005     

Fabrication of strong and thermally more stable jute fabric/polypropylene composites by compression molding along with γ-ray irradiation

Chemically treated jute fabric (TJF)- and untreated jute fabric (UJF)-reinforced isotactic polypropylene (PP)-sandwiched composites, such as TJF composite (TC) and UJF composite (UC), with different JF contents (35–60 wt%) were fabricated by the compression molding technique. Then, PP, UC and TC were irradiated by γ–rays with various doses (0–7.5 kGy) to produce γPP, γUC and γTC, respectively. Water intake (WI), chemical texture, tensile strength (TS), flexural strength (FS), Young’s modulus (Y) and thermal degradation temperatures (T _d) of the samples were examined. Activation energy (E _a) during thermal degradation has been estimated by Broido’s theory. WI in TC, γUC and γTC is lower than that in UC, as accompanied by the change in interfacial textures between JF and PP. The TS, FS, Y, T _d and E _a values of UC, TC, γUC and γTC are found to lie in the ranges 52–61, 55–63, 440–710 MPa, 400–440 °C and 280–340 kJ/mol, respectively. A relative estimation of physical and chemical crosslinking densities/junctions in the composites has been performed and the values have been analyzed by the rubber elasticity and polymer gel theories. The observed changes in physico-mechanical and thermal properties of the composites have been explained on the basis of crosslinking/bonding between JF and PP. Fourier transform infrared spectroscopy confirms the fiber–matrix interactions. A significant increase in Y and T _d values demonstrates a development of strong and thermally more stable JF-reinforced PP composites in the present study.     

Easy-care properties of simultaneously grafted and crosslinked cotton fabrics

The Concurrent grafting of acrylic acid (AA) and crosslinking of dimethylodihydroxyethyleneurea (DMDHEU) with cotton fabric in the presence of ammonium persulfate [(NH₄)₂S₂O₈)], magnesium chloride hexahydrate (MgCl₂ · 6H₂O), and ammonium chloride (NH₄Cl) catalysts were studied. These salts were separately used or as a binary mixture of (NH₄)₂S₂O₈/MgCl₂ · 6H₂O or (NH₄)₂S₂O₈/NH₄Cl. The pad–dry–cure method was employed for the fabric treatment under a variety of conditions. The latter include the nature and kind of the single catalyst as well as pair-mixed catalysts, the concentrations of the catalyst and AA, and temperature and duration of curing. The effects of these conditions on the values of the carboxyl content and crease recovery angle (CRA) of the treated fabrics were evaluted. The tensile strength, elongation at break, dyeability, aqueous and nonaqueous oily soiling, and soil-release properties of the treated fabrics were also examined. Results obtained indicated that all treated fabrics have superior properties, except tensile strength and elongation at break, as compared with the untreated fabric (control). However, beside the AA-grafting and DMDHEU-crosslinking reactions, there are other types of reactions catalyzed by the salts used, viz., the addition reactions between AA molecules and the cellulosic hydroxyls The tentative mechanisms for these reactions are suggested. © 1996 John Wiley & Sons, Inc.     

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.     

Physical properties and reaction kinetics of cotton cellulose crosslinked with dimethyloldihydroxyethyleneurea–maleic acid

Two dicarboxylic acids were used to join with dimethyloldihydroxyethyleneurea (DMDHEU) as crosslinking agents to treated cotton fabrics. These results reveal that the dry crease recovery angle values of the treated fabrics for DMDHEU–maleic acid are higher than those for DMDHEU–tartaric acid at a given wet crease recovery angle and tensile strength retention. The IR spectra show that the reaction between the –OH of DMDHEU and cellulose and the vinyl groups of maleic acids occurred. The cross section of the DMDHEU–maleic acid and DMDHEU–tartaric acid treated fibers and the energies of activation and other data of reaction kinetics for DMDHEU–maleic acid and DMDHEU–tartaric acid strongly suggest that the reaction of vinyl groups of maleic acid with cellulose molecules can take place during the pad/dry‐cure process. Additionally, the surface distribution of crosslinking agent on the finished fabrics for DMDHEU–maleic acid is slightly lower than that for DMDHEU–tartaric acid. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3886–3893, 2004     

CO and CO<Subscript>2</Subscript> Methanation Over Ni/SiC and Ni/SiO<Subscript>2</Subscript> Catalysts

Ni/SiC and Ni/SiO₂ catalysts prepared by both wet impregnation (WI) and deposition–precipitation (DP) methods were compared for CO and CO₂ methanation. The prepared catalysts were characterized using N₂ physisorption, temperature-programmed reduction with H₂ (H₂-TPR), H₂ chemisorption, pulsed CO₂ chemisorption, temperature-programmed desorption of CO₂ (CO₂-TPD), transmission electron microscopy, and X-ray diffraction. H₂-TPR analysis revealed that the catalysts prepared by DP exhibit stronger interaction between the nickel oxides and support than those prepared by WI. The former catalysts exhibit higher Ni dispersions than the latter. The catalytic activities for both reactions over Ni/SiC and Ni/SiO₂ catalysts prepared by WI increase on increasing the Ni content from 10 to 20 wt%. The Ni/SiC catalyst prepared by DP shows higher catalytic activity for CO and CO₂ methanation than that of the Ni/SiC catalyst prepared by WI. Furthermore, it exhibits the highest catalytic activity for CO methanation among the tested catalysts. The high Ni dispersion achieved by the DP method and the high thermal conductivity enabled by SiC are beneficial for both CO and CO₂ methanation.     

Core‐shell ZrO2/PMMA composites via dispersion polymerization in supercritical fluid: Synthesis,characterization and mechanism

In this study, the polyester (PET) fabric was hydrolyzed with alkali to increase the surface activity and enhance the nano titanium dioxide (nano-TiO₂) adsorption to produce higher functionality. The PET fabric was first treated with sodium hydroxide along with cetyl trimethyl ammonium bromide as a cationic surfactant and then dipped into an ultrasound bath containing nano-TiO₂ followed by curing at high temperature. The weight loss, vertical wicking, and water droplet adsorption time were evaluated and are reported. The photocatalytic activity of TiO₂ nanoparticles deposited on the PET fabric was examined by the degradation of methylene blue as a model stain under daylight irradiation. The residual TiO₂ on the fabric surface after 1 and 10 successive washings was determined to indicate the washing durability of the finished fabric. Also, the UV protection was assessed by UV reflectance spectroscopy. The scanning electron microscopy pictures and energy-dispersive X-ray spectra of some fabrics are also reported. The surface hydrolysis of the PET fabric with sodium hydroxide created some voids and hydrophilic groups on the fabric surface; this led to the higher adsorption of nano-TiO₂ particles and enhanced the wettability, vertical wicking, and higher durability against repeated washings of the nano-TiO₂ treated fabric. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Crosslinking of cotton cellulose in the presence of alkyl diallyl ammonium salts. I. Physical properties and agent distribution

We used three kinds of alkyl diallyl ammonium salts (methyl, ethyl, and propyl) in combination with dimethyloldihydroxyethyleneurea (DMDHEU) as crosslinking agents. The nitrogen content, dry crease recovery angle (DCRA), moisture regain, and wicking height for the DMDHEU/alkyl diallyl ammonium salts were in the order of ? CH₃ > ? C₂H₅ > ? C₃H₇, but the wet crease recovery angle (WCRA) and tensile strength retention (TSR) were in the opposite order at the same resin concentration. For the same DCRA and TSR, the WCRA values for only DMDHEU were lower than those for DMDHEU/alkyl diallyl ammonium salts, and the WCRA values for DMDHEU/alkyl diallyl ammonium salts were in the order of ? C₃H₇ > ? C₂H₅ > ? CH₃. Both the ? OH group of the cellulose and DMDHEU could react with the vinyl or epoxy groups of the alkyl diallyl ammonium salts during the pad–dry–cure process. The surface migration for DMDHEU/alkyl diallyl ammonium salts was in the order of ? CH₃ > ? C₂H₅ > ? C₃H₇. Fabrics treated with DMDHEU/alkyl diallyl ammonium salts showed good antibacterial properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1662–1669, 2003     

Electron spectroscopy for chemical analyses (ESCA)—A tool for studying treated textiles

Electron spectroscopy for chemical analysis (ESCA) has been successfully used to determine the location of flame-retardant polymers or reagents and crosslinking and oil/water-repellent reagents in relation to fiber surfaces of chemically modified cotton fabrics and cotton/polyester blends. Changes in intensity of characteristic ESCA element signals were followed as the particle size of the treated fabric varied. Dimethyloldihydroxyethyleneurea (DMDHEU) and the flame-retardant polymer formed from tetrakis(hydroxymethyl)phosphonium chloride (Thpc) and urea penetrate and are homogeneously deposited throughout cotton fabrics. The oil/water-repellent finish, FC-218, and the flame retardants from the THPOH/NH₃ reaction and tris(dibromopropyl) phosphate are deposited on the surfaces of both cotton and polyester fibers.     

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     

Au/TS‐1 catalyst for propene epoxidation with H2/O2: A novel strategy to enhance stability by tuning charging sequence

For propene epoxidation with H₂ and O₂, the catalytic performance of Au/TS‐1 catalyst is extremely sensitive to preparation parameters of deposition‐precipitation (DP) method. In this work, effect of charging sequence in DP process on catalyst structure and catalytic performance of Au/TS‐1 catalyst is first investigated. For different charging sequences, the compositions of Au complexes (e.g., [AuCl(OH)₃]^?) and pore property of TS‐1 (i.e., with or without H₂O prefilling micropores) could affect the transfer of Au complexes into the micropores, resulting in different Au locations and thus significantly different catalytic performance. Notably, when TS‐1 is first filled with H₂O and then mixed with Au complexes, the reduced Au/TS‐1 catalyst could expose Au nanoparticles on the external surface of TS‐1 and show high stability. The results provide direct evidence showing that micropore blocking is the deactivation mechanism. Based on the results, a simple strategy to design highly stable Au/Ti‐based catalysts is developed. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3963–3972, 2016