Hydrolysis mechanism of crosslinks formed between hydroxymethylated 2-substituted 4,6-diamino-s-triazines and cotton

Hydrolysis resistance and mechanism of reaction products of hydroxymethylated 2-substituted (X) 4,6-diamino-s-triazines (MXT) with cotton fabrics has been studied. Finishing reagents used were MXT having the following substituents: X = CH₃O? (MMT), (CH₃)₂CHO? (MIPT), CH₃? (MAG), C₂H₅NH? (MEM), HOC₂H₄NH? (MHEM), and (HOC₂H₄)₂N? (MBHEM). For comparison, trimethylolmelamine (TMM), dimethylolurea (DMU), dimethylolethyleneurea (DMEU), and dimethylol-ethyltriazone (DMET) were used. Hydrolysis was carried out in buffer and NaOH solutions of various pH's for 30 min at 80°C. The order of hydrolysis resistance of crosslinked reagents was determined from the nitrogen contents retained. It was as follows: pH 1, MROT < MRNT < MRT; pH ≧ 2, MROT > MRT > MRNT; pH ≦ 13, MROT > MRNT; pH 14, MROT < MRT < MRNT, where MROT is hydroxymethylated 2-alkoxy (MMT, MIPT), MRT is hydroxymethylated 2-alkyl (MAG), and MRNT is hydroxymethylated 2-alkylamino-4,6-diamino-s-triazine (MEM, MHEM, MBHEM). This fact can be explained in terms of the basicity constant (p^K_b) of crosslinked MXT with cotton (approximately p^K_b) of 2-substituted 4,6-diamino-s-triazine (XT). The hydrolysis rates of crosslinked MMT, MAG, and MEM were determined at pH 2. The activation energies were 21.8 for MMT, 20.9 for MAG, and 21.0 kcal/mole for MEM.     

Application of DMEU/SiO2 gel solution in the antiwrinkle finishing of cotton fabrics

In this experiment, cotton fabrics were treated by padding, drying, and curing with an antiwrinkle finishing reagent, dimethylolethylene urea (DMEU), in combination with different concentrations of tetraethoxysilane (TEOS) and isopropanol (IPA) at various volumes. The treated fabrics were studied to determine the effects of adding TEOS and IPA. They were also analyzed using Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) methods to examine the binding between SiO₂ and DMEU. The results showed that hydrogen bonds formed between SiO₂ and DMEU. TEOS was found to improve the antiwrinkle properties, tensile strength retention, and yellowing of the treated fabrics, although their softness was slightly reduced. The solvent IPA was shown to decrease the tensile strength of treated fabrics, although it improved their antiwrinkle properties. We observed only one stage of pyrolysis in untreated cotton fabrics, whereas the treated fabrics showed two stages. In addition, the fabrics treated with TEOS showed improved heat resistance. Our findings demonstrated that cotton fabrics showed excellent antiwrinkle properties and high tensile strength, when treated with a finishing solution composed of DMEU, 3% TEOS, IPA and water, followed by predrying and curing. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4136–4143, 2006     

Kinetic studies of crease‐resistant finishing process for cotton fabrics with DMEU/MMEU prepolymer mixture

The kinetics of the crease‐resistant finishing process for cotton fabrics with DMEU/MMEU prepolymer mixture are studied. The DMEU/MMEU prepolymer resin is made from ethylene urea (EU) and paraformaldehyde (PF) with different mole ratios. The results show that the nitrogen content in the treated fabrics and the reaction rate constant increases with curing temperature and PF mole ratio. The treated fabrics with more PF in the source material have smaller E_a, Δ H*ast;, and ΔS*. The ΔG* was independent of the mole ratio in the source material, but it increases with curing temperature. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 509–513, 2002     

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.     

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.     

Physical properties of cotton fabrics and free CH2O content in crease‐resistant finish with DMEU/MMEU prepolymer mixture

Combinations of ethylene urea and paraformaldehyde with different mol ratios are used as source materials to synthesize a DMEU/MMEU resin prepolymer in various mixing ratios. The DMEU/MMEU resin prepolymer is then applied to the crease‐resistant finish of cotton fabrics. The results show that the dry and wet crease‐recovery angles and nitrogen and free formaldehyde contents increase with increasing curing time, curing temperature, and mol ratio of paraformaldehyde, while the tensile strength retention decreases. Optimized relations between both physical and chemical properties can be obtained by mixing the source materials in a 1 : 1.5–1 : 1.7 ratio, drying at 80°C for 5 min, and curing at 150°C for 3 min. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 390–395, 2000     

The study of rapid curing crease‐resistant processing on cotton fabrics. Part I. The effect of chitosan on the physical properties of processed fabrics

The principal aim of this study is to explore the effect of chitosan on the physical properties of cotton fabrics in rapid curing crease‐resistant processing. It was determined that compared with the traditional three‐stage processing, the addition of chitosan is beneficial to the absorbency of processed fabrics, dry‐wet wrinkle recovery angle, and tensile strength retention. In addition, the dry‐wet wrinkle recovery angle of processed fabrics increases with the increase of curing temperature and curing treatment time, but absorbency and tensile strength retention both decrease. Also, the dry‐wet wrinkle recovery angle and tensile strength retention of processed fabrics increase with higher chitosan concentrations, but the fabric's absorbency is reduced. In general, use of 0.5%≈︁0.75% chitosan with DMEU curing treatment conditions of 8%, 200°C for 30 s will provide optimum physical property balance for processed fabrics. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 35–40, 2000     

Functional copolymers with retention properties for heavy metal ions

Summary Poly (N-phenylmaleimide-co-2-methylaziridine); poly [p-methylphenyl-maleimide-co-1-(2-hydroxyethyl)aziridine]; poly [p-methoxyphenylmaleimide-co-1-(2-hydroxyethyl)aziridine] and poly [N-phenylmaleimide-co-1-(2-hydroxyethyl)aziridine] were synthesized by spontaneous coplymerization. All the resins were insoluble in water. It was found that the resins with 1-(2-hydroxyethyl)aziridine moiety showed the highest adsorption ability for uranium.     

Effect of chitosan addition to BTCA/CA processed cotton fabrics for adsorbing metallic ions from waste water

One of the most important properties of chitosan, a derivative of chitin, is that it is able to chelate with certain heavy metal ions, and this property can be applied to process waste water containing heavy metal ions. In this research, using BTCA/CA as a crosslinking reagent with chitosan added, cotton fabrics were cured and allowed to undergo an adsorption reaction in CuSO₄ and ZnSO₄ solutions. The effect of different curing temperatures and time, as well as different adsorptive temperatures and time, were studied. The cotton processed fabrics were analyzed by Fourier transform infrared analysis (FTIR), scanning electronic microscope (SEM), and thermal gravity analysis (TGA) to study the crosslinking reaction with the cotton‐processed fabrics. The results indicate: (1) the BTCA/CA‐processed cotton fabrics with an addition of chitosan have a better adsorptive capacity than the processed fabrics without chitosan; (2) the crosslinked fabrics are better in adsorbing copper ions as chitosan concentration, curing temperature and time, and adsorptive temperature and time increase; (3) the adsorption rate of copper and zinc ions are linearly proportional to the changes of time, so that the slope shows that the adsorption rate of crosslinked fabrics for copper ions is faster than for zinc ions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3264–3269, 2006     

New 3,6-dihalogencarbazole-containing monomers and polymers

Summary The synthesis of six novel electrono-donor monomers containing 3,6-dihalogencarbazole [N-(2-hydroxyethyl)-3, 6-dichlorocarbazolyl methacrylate, N-(2-hydroxyethyl)-3, 6-dichlorocarbazolyl acrylate, N-(2-hydroxyethyl)-3, 6-dibromocarbazolyl methacrylate, N-(2-hydroxyethyl)-3, 6-dibromocarbazolyl acrylate, N-(2-hydroxyethyl)-3, 6-diiodocarbazolyl methacrylate and N-(2-hydroxyethyl)-3,6-diiodocarbazolyl acrylate], of the corresponding polymers and of the monomeric models is described. The ionization potentials values of the monomeric models were determined.     

环氧树脂/三羟甲基三聚氰胺硅化物固化体系阻燃性能与耐热性研究

利用三聚氰胺和甲醛合成了三羟甲基三聚氰胺（TMM）,将其与正硅酸乙酯(TEOS)反应得到三羟甲基化三聚氰胺硅化物（TMMSi）。将TMMSi与环氧树脂复合,采用4,4'-二氨基二苯基甲烷(DDM)作固化剂来制备环氧树脂/TMMSi固化物,并对固化物的热性能和阻燃性能进行了分析。结果表明,与环氧树脂/TMM固化物相比,环氧树脂/TMMSi固化物的玻璃化转变温度变化较小,高温耐热性提高不明显,但是阻燃性能得到了大幅度提高。当TMMSi含量为15份时,环氧树脂/TMMSi固化物的极限氧指数达到29.6 %,比纯环氧树脂固化物提高了40 %。     

水溶性萘酰亚胺氢离子荧光分子探针的合成及性能

4 溴 1,8 萘酐与羟乙氧基乙胺反应合成了中间体N 羟乙氧基乙基 4 溴 1,8 萘酰亚胺。用该中间体分别与哌嗪、甲基哌嗪和羟乙基哌嗪反应 ,合成了 4 哌嗪基、4 (甲基哌嗪 )基和 4 (羟乙基哌嗪 )基 1,8 萘酰亚胺衍生物 (NP - 1、NP - 2和NP - 3)。这 3种化合物具有较好的水溶性 ,其水溶液的荧光强度随溶液由碱性到酸性变化 ,荧光强度增加在 5 0倍以上。NP - 1、NP - 2和NP - 3的pK′a值分别为 8 5、7 6和 6 7。     

Synthesis and properties of hydrophilic polymers. III. Ligand effects of the side chains of polyaziridines on metal complexation in aqueous solution

The metal-complexing properties of five different polyaziridines—poly[1-(2-aminoethyl)aziridine], poly(1-acetylaziridine), poly[1-(2-hydroxyethyl)aziridine], poly[1-(2-hydroxyethyl)aziridine-co-1-acetylaziridine], and poly[1-(2-aminoethyl)aziridine] oxine—were investigated in an aqueous solution with regard to the side-chain effects using membrane filtration. The results are discussed and compared with the stability constants of metalcomplexation of the corresponding functional moieties. Poly[1-(2-aminoethyl)aziridine], a poly(aziridine) with neutral nitrogen donors in the side chains, showed similar complexing properties to those of ammonia. The only exceptions are Fe(III) and Cr(III), which cannot form complexes with ammonia but can be retained in the membrane filtration process due to the formation of Fe(III)-colloidal species and hydroxides. The complexing properties of polyaziridines containing hydroxyl groups in the side chains (i.e., poly[1-(2-hydroxyethyl)aziridine] and poly[1-(2-hydroxyethyl) aziridine-co-1-acetylaziridine] can be explained and described by the formation constants with the corresponding hydroxides. The introduction of a carbonyl moiety in the polyaziridine side chain, e.g., polyacetylaziridine, reduces the complexing ability for metal ions because the carbonyl group cannot form complexes with the metal ions investigated. Poly[1-(2-aminoethyl)aziridine]oxine showed the strongest complexing ability in the series of metal ions due to the strong complexing ligand 8-hydroxy quinoline attached to the polymer backbone. © 1996 John Wiley & Sons, Inc.     

Über neue Pyrazolverbindungen. IV Darstellung und Cyclisierungsverhalten einiger akzeptorsubstituierter N-(Pyrazol-3-yl)-thioharnstoffe

New Pyrazol Derivatives. IV. Preparation and Cyclization of Some Acceptor-Substituted N-(Pyrazol-3-yl)-thioureas . 3-Aminopyrazol-4-carboxylic acid derivatives ( 1 , 2 ) were transformed by reaction with different isothiocyanates R²NCS to N-(pyrazol-3-yl)-N^. -substituted thioureas ( 5 , 6 ). Ethyl 3-amino-1-benzylpyrazol-4-carboxylate reacts with CSCl₂ to form ethyl 1-benzyl-3-isothiocyanatopyrazol-4-carboxylate ( 3 ) which yields with amines the corresponding N-(pyrazol-3-yl)-N^. -substituted thioureas ( 5 ). As a byproduct in the reaction with CSCl₂ N,N^. -di-(pyrazol-3-yl)-thiourea ( 4 ) is formed. With hydrazine or phenylhydrazine N-(pyrazol-3-yl)-thiosemicarbazides ( 7a , b ) are obtained. The thioureas ( 5 , 6 ) can be cyclized in basic solution to 4,5,6,7-tetrahydropyrazolo[3,4-d]pyrimidin-4-on-6-thiones ( 8 ) which on alkylation form 6-alkylthio-4,5-dihydropyrazolo[3,4-d]pyrimidin-4-ones ( 9 ). Methyl-N-(pyrazol-3-yl)-N^.-benzoylisothiourea ( 10 ) reacts with ethylamine to form N-benzoyl-N^. -ethyl-N^‥-(pyrazol-3-yl)-guanidine derivative ( 11 ) which on treatment with NaH in dimethylformamide yields 6-benzoylamino-5-ethyl-4,5-dihydropyrazolo[3,4-d]pyrimidin-4-one ( 12 ). By treatment with sulfuric acid the N-(pyrazol-3-yl)-thiourea derivatives ( 5 , 6 ) form new 6-amino substituted pyrazolo[3,4-d][1,3]thiazin-4-ones ( 13 ).     

Synthesis,Characterization and Glass-reinforced Composites of Trimethylolmelamine-phenol Resins

Abstract

Trimethylolmelamine (TMM) has been prepared and characterized. The TMM condensed with phenol in the presence of alkali catalyst at the varying ratios of TMM: Phenol, viz. 1:1, 1:1.5 and 1:2. The resultant triazine ring containing resins (TMMP) were characterized by elemental analyses, IR spectral studies and thermogravimetry. The isothermal curing study of TMMP resin with hexamethylenetetramine (HMTA) was also carried out. Finally, the glass-reinforced composites based on TMMP-HMTA system have also been prepared and characterized for synergetic property combination of both MF and PF.     

Tensile recoveries of cotton modified with and without crosslinks

When effect of the substrate is nullified, resiliency can be defined as a function of strain, time, and humidity. Determination of improvement in the immediate, or rapid, tensile recovery readily delineates differences due to chemical modifications. Delayed recovery is usually less improved than immediate. Crosslinking cotton with dimethylolethyleneurea (DMEU) increases tensile strain recovery as the number of crosslinks increase, reduces dependency of recovery upon external strain, and produces maximum recovery at about 65% R.H. Noncrosslinking treatments produce limited increases in tensile strain recovery. Measurements on yarns crosslinked with DMEU and then hydrolyzed indicate that incalculably few residual links may contribute to tensile recovery. N-Methylol-N'-methylethyleneurea treated cotton displays physical blocking and water swelling which aid recovery. Oleoyl chloride esterified cellulose has tensile recovery probably due to molecular entanglements. Its delayed or viscoelastic recovery is the most improved with immediate recovery being the least improved. The higher the moisture regain, the greater tensile modulus reduction under wet conditions. Crosslinking with DMEU under dry conditions lessens this reduction in modulus. Improvements in the tensile recovery of strain and energy, for all samples and with varied conditions of humidity and strain, correspond linearly with unit slope.     

Synthesis and application of dual-curable PVB based adhesive formulations for cord/rubber applications

In this research, formaldehyde-free dual-curable adhesive formulations containing polyvinyl butyral (PVB) were prepared with the reaction of 2,4-toluene diisocyanate (TDI) and 2-hydroxyethyl methacrylate (HEMA) and then applied on cord fabrics upon adhere onto the rubber surfaces. The effects of PVB ratio on peel strength value between the cord and rubber were studied. The structure of the oligomer was characterized by FTIR and ¹H NMR spectroscopy. Thermal properties of coated and UV-cured fabrics were investigated by TGA and DSC. Surface wettability properties of the fabrics after coating were observed with contact angle measurement. The peel strength between cord/rubber surfaces was determined by T-peel test after thermal curing stage under heat and pressure. Results showed that peel strength value increases with increasing PVB amount in the formulation. The highest peel strength of 94.7 N/cm was observed when 5% PVB was included in the formulation. This study leads to a new type of promising adhesives with superior peel strength for cord/rubber applications as it is being a totally formaldehyde-free process.     

Degree of crosslinking and physical properties of dimethyloldihydroxyethyleneurea/acrylic acid crosslinked cotton fabrics after treatment with various metallic salts

Three metallic salts were used to posttreat dimethyloldihydroxyethyleneurea (DMDHEU)/acrylic acid (AA) crosslinked cotton fabrics, and the results showed that at a given value of the tensile strength retention (TSR), the dry crease recovery angle (DCRA) and wet crease recovery angle (WCRA) of the crosslinked and posttreated fabrics were higher than those of the DMDHEU–AA‐treated fabrics, and those of the crosslinked and posttreated fabrics were in the order of Ag⁺ > Cu⁺² > Al⁺³. The DCRA and TSR values for the crosslinked and posttreated fabrics were higher than those for the DMDHEU–AA‐crosslinked fabrics, and those for the crosslinked and posttreated fabrics were in the order of Ag⁺ > Cu⁺² > Al⁺³; however, WCRA values for the crosslinked and posttreated fabrics were lower than those for the DMDHEU–AA‐crosslinked fabrics, and those for the crosslinked and posttreated fabrics were ranked as Ag⁺ > Cu⁺² > Al⁺³ at a given number of crosslinks per anhydroglucose unit. IR spectra clearly revealed the different interactions and bonding states between the hydroxyl group of the cellulose and the various metallic ions and the strength of the interaction. All crosslinked and posttreated fabric samples showed good odor absorption and antibacterial and washing‐fastness properties. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 584–594, 2005     

The effect of TiO2, pigmentation on the hydrolysis of amino resin crosslinked epoxy can coatings

Pigmented (TiO₂), amino resin crosslinked coatings, designed for applications in can coatings’ internal lacquers, were formulated, characterized, applied, and cured. Three grades of a pigmentary form of TiO₂ were characterized in terms of their particle size, their particle morphology, their zeta potential, and their moisture retention behavior. Epoxy coatings that were crosslinked using one of several, different amino crosslinkers were prepared. The effect of the presence of the TiO₂ pigments on the hydrolysis of the cured coatings was monitored via the controlled retorting of the coatings. The different grades of TiO₂ pigment were selected, to establish whether or not they could be used interchangeably with respect to hydrolysis and to melamine release. Also, the effects of the aging of the fluid coatings on the amount of melamine released from the coatings (after curing and retorting) were monitored. Storage under laboratory conditions for 2, 20, and 40 weeks was used for this purpose. The TiO₂ pigment contributed significantly to the hydrolysis behavior of the epoxy coatings in that their presence substantially reduced the amount of melamine released and the extent of crosslinker hydrolysis. Typical results show that excluding the TiO₂ pigment particles from the formulation results in there being 50% more hydrolysis of the crosslinker to melamine. With respect to the melamine release and crosslinker hydrolysis, the different grades of the pigment gave similar results.     

Synthesis and Characterization of Linear Homopolyesters Containing s-Triazine Rings

Eight homopolyesters were synthesized by high temperature polycondensation of 2-(N-1-naphthylamine)-4,6-bis (naphthoxy-2-carbonyl chloride)-s-triazine [NANCCT]with each of the eight diols: Bisphenol-A(BPA), bisphenol-C(BPC), phenolphthalein(ph), resorcinol(R), hydroquinone(Hq), catechol(C), 1,5-dihydroxy naphthalene (1, 5-DHN), and ethylene glycol (EG). All the polyesters were characterized by solubility, density, viscosity measurements, IR spectra, NMR spectroscopy, and thermogravimetric analysis.